From 6eb6dd05a310709470358270a670a75ac7657a87 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 01:58:45 +0100
Subject: [PATCH 01/67] Set newer expectations

---
 README.md | 32 +++++++++++++++++++++-----------
 RULES.md  |  4 ----
 2 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/README.md b/README.md
index 8a9f7141..1d53ea5b 100644
--- a/README.md
+++ b/README.md
@@ -37,19 +37,28 @@ Once this is done you can apply the style rules in the following ways.
 #### Loading configuration from a file
 
 ```shell
-1> ElvisConfig = elvis_config:from_file("elvis.config").
+1> ElvisConfig = elvis_config:config().
 <loaded_config>
 2> elvis_core:rock(ElvisConfig).
+Loading src/elvis_code.erl
+# src/elvis_code.erl [OK]
+Loading src/elvis_config.erl
+# src/elvis_config.erl [OK]
+Loading src/elvis_core.erl
 # src/elvis_core.erl [OK]
-# src/elvis_result.erl [OK]
-# src/elvis_style.erl [OK]
-# src/elvis_utils.erl [OK]
+Loading src/elvis_file.erl
+# src/elvis_file.erl [OK]
+...
 ok
 3>
 ```
 
 This will load the [configuration](#configuration), specified in file `elvis.config`, from the
-current directory. If no configuration is found `{invalid_config, _}` is thrown.
+current directory.
+
+If `elvis.config` is not present, the application will fall back to searching for configuration
+parameters in `rebar.config`. If `rebar.config` is also unavailable, the application proceeds to
+perform a tertiary lookup within the `app/sys.config` file for the required settings.
 
 #### Providing configuration as a value
 
@@ -60,14 +69,15 @@ an argument to `elvis_core:rock/1`:
 1> ElvisConfig = [#{dirs => ["src"], filter => "*.erl", rules => []}].
 [#{dirs => ["src"],filter => "*.erl",rules => []}]
 2> elvis_core:rock(ElvisConfig).
+Loading src/elvis_code.erl
+# src/elvis_code.erl [OK]
+Loading src/elvis_config.erl
+# src/elvis_config.erl [OK]
 Loading src/elvis_core.erl
 # src/elvis_core.erl [OK]
-Loading src/elvis_result.erl
-# src/elvis_result.erl [OK]
-Loading src/elvis_style.erl
-# src/elvis_style.erl [OK]
-Loading src/elvis_utils.erl
-# src/elvis_utils.erl [OK]
+Loading src/elvis_file.erl
+# src/elvis_file.erl [OK]
+...
 ok
 3>
 ```
diff --git a/RULES.md b/RULES.md
index 39cca9cd..3e0885aa 100644
--- a/RULES.md
+++ b/RULES.md
@@ -222,10 +222,6 @@ for `.hrl` files.
          , filter => "*.hrl"
          , ruleset => hrl_files
          }
-      , #{ dirs => ["."]
-         , filter => "Makefile"
-         , ruleset => makefiles
-         , rules => [] }
       , #{ dirs => ["."]
          , filter => "rebar.config"
          , ruleset => rebar_config

From da75963badad3198c3b39ea4c8669ff272f77a1d Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 02:46:26 +0100
Subject: [PATCH 02/67] Expect to move keys (and default handling) to
 elvis_config

---
 src/elvis_core.erl   | 4 ++--
 src/elvis_result.erl | 2 +-
 src/elvis_utils.erl  | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index d3307645..cee64042 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -76,7 +76,7 @@ rock_this(Path, ElvisConfig) ->
     ok
     | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 do_parallel_rock(ElvisConfig0) ->
-    Parallel = elvis_config:from_application_or_config(parallel, 1),
+    Parallel = elvis_config:parallel(),
     ElvisConfig = elvis_config:resolve_files(ElvisConfig0),
     Files = elvis_config:files(ElvisConfig),
 
@@ -126,7 +126,7 @@ load_file_data(ElvisConfig, File) ->
 main([]) ->
     ok = application:load(elvis_core),
     {module, _} = code:ensure_loaded(elvis_style),
-    case rock(elvis_config:from_file("elvis.config")) of
+    case rock(elvis_config:config()) of
         ok -> true;
         _ -> halt(1)
     end.
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index c2cc10c1..71440e67 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -167,7 +167,7 @@ get_line_num(#{line_num := LineNum}) ->
 
 -spec print_results(file() | [elvis_warn()]) -> ok.
 print_results(Results) ->
-    Format = elvis_config:from_application_or_config(output_format, colors),
+    Format = elvis_config:output_format(),
     print(Format, Results).
 
 -spec print(plain | colors | parsable, [file()] | file()) -> ok.
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 079a3e30..ad6803a1 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -61,7 +61,7 @@ warn_prn(Message, Args) ->
 
 -spec print_info(string(), [term()]) -> ok.
 print_info(Message, Args) ->
-    case elvis_config:from_application_or_config(verbose, false) of
+    case elvis_config:verbose() of
         true ->
             print(Message, Args);
         false ->
@@ -70,7 +70,7 @@ print_info(Message, Args) ->
 
 -spec print(string(), [term()]) -> ok.
 print(Message, Args) ->
-    case elvis_config:from_application_or_config(no_output, false) of
+    case elvis_config:no_output() of
         true ->
             ok;
         _ ->
@@ -93,7 +93,7 @@ parse_colors(Message) ->
             "reset" => "\e[0m"
         },
     Opts = [global, {return, list}],
-    case elvis_config:from_application_or_config(output_format, colors) of
+    case elvis_config:output_format() of
         P when P =:= plain; P =:= parsable ->
             re:replace(Message, "{{.*?}}", "", Opts);
         colors ->

From 9d596a44a87299ca82fe8e55a28cd9955e187399 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 03:15:25 +0100
Subject: [PATCH 03/67] Approach our expectations on continuing validation

---
 src/elvis_config.erl | 136 +++++++++++++++++++++++++++++--------------
 src/elvis_core.erl   |  23 ++++++--
 2 files changed, 110 insertions(+), 49 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index baf7871c..80947d49 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -2,12 +2,7 @@
 
 -feature(maybe_expr, enable).
 
--export([
-    from_rebar/1,
-    from_file/1,
-    from_application_or_config/2,
-    validate/1
-]).
+-export([from_rebar/1, from_file/1, validate/1]).
 %% Geters
 -export([dirs/1, ignore/1, filter/1, files/1, rules/1]).
 %% Files
@@ -15,63 +10,114 @@
 %% Rules
 -export([merge_rules/2]).
 
--export_type([t/0]).
+%% Options
+-export([config/0, output_format/0, verbose/0, no_output/0, parallel/0]).
 
 -type t() :: map().
+-export_type([t/0]).
+
+-type validation_error() :: empty_config.
+-export_type([validation_error/0]).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
--spec from_rebar(string()) -> [t()].
-from_rebar(Path) ->
-    case file:consult(Path) of
-        {ok, AppConfig} ->
-            load(config, load_initial(AppConfig), []);
-        {error, Reason} ->
-            throw(Reason)
-    end.
+load_elvis(AppConfig) ->
+    ElvisConfig = proplists:get_value(elvis, AppConfig, default(elvis)),
+    elvis_ruleset:set_rulesets(proplists:get_value(rulesets, ElvisConfig, default(rulesets))),
+    ElvisConfig.
 
--spec from_file(string()) -> [t()].
-from_file(Path) ->
-    from_file(Path, config, []).
+config() ->
+    for(config).
 
--spec from_file(string(), atom(), term()) -> [t()].
-from_file(Path, Key, Default) ->
-    case file:consult(Path) of
-        {ok, [AppConfig]} ->
-            load(Key, load_initial(AppConfig), Default);
-        {error, {_Line, _Mod, _Term} = Reason} ->
-            throw(Reason);
-        {error, _Reason} ->
-            Default
-    end.
+output_format() ->
+    for(output_format).
+
+verbose() ->
+    for(verbose).
+
+no_output() ->
+    for(no_output).
 
--spec from_application_or_config(atom(), term()) -> term().
-from_application_or_config(Key, Default) ->
+parallel() ->
+    for(parallel).
+
+default(Key) ->
     case application:get_env(elvis_core, Key) of
+        undefined ->
+            default_for(Key);
         {ok, Value} ->
-            Value;
-        _ ->
-            from_file("elvis.config", Key, Default)
+            Value
     end.
 
--spec load(atom(), term(), term()) -> [t()].
-load(Key, ElvisConfig, Default) ->
-    proplists:get_value(Key, ElvisConfig, Default).
+for(Key) ->
+    AppConfig =
+        case consult_elvis_config(default) of
+            [] ->
+                consult_rebar_config(default);
+            AppConfig0 ->
+                AppConfig0
+        end,
+    TopLevelCfg = load_elvis(AppConfig),
+    proplists:get_value(Key, TopLevelCfg, default(Key)).
+
+consult_elvis_config(File0) ->
+    File =
+        case File0 of
+            default ->
+                "elvis.config";
+            _ ->
+                File0
+        end,
+    case file:consult(File) of
+        {ok, [AppConfig]} ->
+            AppConfig;
+        _ ->
+            []
+    end.
 
--spec load_initial(term()) -> [term()].
-load_initial(AppConfig) ->
-    ElvisConfig = proplists:get_value(elvis, AppConfig, []),
-    RulesetsConfig = proplists:get_value(rulesets, ElvisConfig, #{}),
-    elvis_ruleset:set_rulesets(RulesetsConfig),
-    ElvisConfig.
+consult_rebar_config(File0) ->
+    File =
+        case File0 of
+            default ->
+                "rebar.config";
+            _ ->
+                File0
+        end,
+    case file:consult(File) of
+        {ok, AppConfig0} ->
+            AppConfig0;
+        _ ->
+            []
+    end.
 
--spec validate(Config :: [t()]) -> ok.
+from_rebar(File) ->
+    RebarConfig = consult_rebar_config(File),
+    TopLevelCfg = load_elvis(RebarConfig),
+    Key = config,
+    proplists:get_value(Key, TopLevelCfg, default(Key)).
+
+from_file(File) ->
+    FileConfig = consult_elvis_config(File),
+    TopLevelCfg = load_elvis(FileConfig),
+    Key = config,
+    proplists:get_value(Key, TopLevelCfg, default(Key)).
+
+default_for(elvis) -> [];
+default_for(config) -> [];
+default_for(output_format) -> colors;
+default_for(verbose) -> false;
+default_for(no_output) -> false;
+default_for(parallel) -> 1;
+default_for(rulesets) -> #{}.
+
+-spec validate(Config :: [t()]) -> [validation_error()].
 validate([]) ->
-    throw({invalid_config, empty_config});
+    [empty_config];
 validate(Config) ->
-    lists:foreach(fun do_validate/1, Config).
+    lists:foreach(fun do_validate/1, Config),
+    [].
 
 do_validate(RuleGroup) ->
     maybe
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index cee64042..899d9902 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -31,20 +31,35 @@ start() ->
     ok.
 
 -spec rock([elvis_config:t()]) ->
-    ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
+    ok | {fail, [FailThrow | FailFile | FailRules | FailInvalid]}
+when
+    FailThrow :: {throw, term()},
+    FailFile :: elvis_result:file(),
+    FailRules :: elvis_result:rule(),
+    FailInvalid :: {elvis_config, [elvis_config:validation_error()]}.
 rock(ElvisConfig) ->
-    ok = elvis_config:validate(ElvisConfig),
+    _IsValid = elvis_config:validate(ElvisConfig),
+    continue_to_rock({_StopOnErrors = false, []}, ElvisConfig).
+
+continue_to_rock({false = _StopOnErrors, _Errors}, ElvisConfig) ->
     Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
     lists:foldl(fun combine_results/2, ok, Results).
 
 -spec rock_this(target(), [elvis_config:t()]) ->
-    ok | {fail, [elvis_result:file() | elvis_result:rule()]}.
+    ok | {fail, [FailFile | FailRule | FailInvalid]}
+when
+    FailFile :: elvis_result:file(),
+    FailRule :: elvis_result:rule(),
+    FailInvalid :: {throw, {elvis_config, [elvis_config:validation_error()]}}.
 rock_this(Module, ElvisConfig) when is_atom(Module) ->
     ModuleInfo = Module:module_info(compile),
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
-    elvis_config:validate(ElvisConfig),
+    _IsValid = elvis_config:validate(ElvisConfig),
+    continue_to_rock_this({_StopOnErrors = false, []}, Path, ElvisConfig).
+
+continue_to_rock_this({false = _StopOnErrors, _Errors}, Path, ElvisConfig) ->
     Dirname = filename:dirname(Path),
     Filename = filename:basename(Path),
     File =

From 38f0ae4ba3f7579858ff7b75bd06e3b70c267f43 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 03:32:02 +0100
Subject: [PATCH 04/67] Implement mechanism to prevent re-validation

(since we have no other state to work with, at the moment)
---
 src/elvis_config.erl | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 80947d49..ed67b858 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -343,3 +343,36 @@ is_rule_override(Rule, UserRules) ->
         end,
         UserRules
     ).
+
+flag_validated(Option) ->
+    Table = table(),
+    _ = create_table(Table),
+    Obj = validated_flag(Option),
+    ets:insert(Table, Obj).
+
+is_validated(Option) ->
+    Table = table(),
+    case table_exists(Table) of
+        false ->
+            false;
+        _ ->
+            Obj = validated_flag(Option),
+            ets:lookup(Table, Option) =:= [Obj]
+    end.
+
+validated_flag(Option) ->
+    {Option, validated}.
+
+create_table(Table) ->
+    case table_exists(Table) of
+        false ->
+            _ = ets:new(Table, [public, named_table]);
+        _ ->
+            ok
+    end.
+
+table() ->
+    ?MODULE.
+
+table_exists(Table) ->
+    ets:info(Table) =/= undefined.

From 60d2d0b6ab427fe710c4b7932f3d8f0c1d9defec Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 11:54:20 +0100
Subject: [PATCH 05/67] Go back to elvis_core as is: leave validation to
 elvis_config

... and consumers
---
 src/elvis_core.erl | 23 ++++-------------------
 1 file changed, 4 insertions(+), 19 deletions(-)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 899d9902..cee64042 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -31,35 +31,20 @@ start() ->
     ok.
 
 -spec rock([elvis_config:t()]) ->
-    ok | {fail, [FailThrow | FailFile | FailRules | FailInvalid]}
-when
-    FailThrow :: {throw, term()},
-    FailFile :: elvis_result:file(),
-    FailRules :: elvis_result:rule(),
-    FailInvalid :: {elvis_config, [elvis_config:validation_error()]}.
+    ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
-    _IsValid = elvis_config:validate(ElvisConfig),
-    continue_to_rock({_StopOnErrors = false, []}, ElvisConfig).
-
-continue_to_rock({false = _StopOnErrors, _Errors}, ElvisConfig) ->
+    ok = elvis_config:validate(ElvisConfig),
     Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
     lists:foldl(fun combine_results/2, ok, Results).
 
 -spec rock_this(target(), [elvis_config:t()]) ->
-    ok | {fail, [FailFile | FailRule | FailInvalid]}
-when
-    FailFile :: elvis_result:file(),
-    FailRule :: elvis_result:rule(),
-    FailInvalid :: {throw, {elvis_config, [elvis_config:validation_error()]}}.
+    ok | {fail, [elvis_result:file() | elvis_result:rule()]}.
 rock_this(Module, ElvisConfig) when is_atom(Module) ->
     ModuleInfo = Module:module_info(compile),
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
-    _IsValid = elvis_config:validate(ElvisConfig),
-    continue_to_rock_this({_StopOnErrors = false, []}, Path, ElvisConfig).
-
-continue_to_rock_this({false = _StopOnErrors, _Errors}, Path, ElvisConfig) ->
+    elvis_config:validate(ElvisConfig),
     Dirname = filename:dirname(Path),
     Filename = filename:basename(Path),
     File =

From 6bf4ceb73289b47a10d437e922524d0ce3cd0fb9 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sat, 5 Jul 2025 13:49:39 +0100
Subject: [PATCH 06/67] Make it easier to debug and formulate newer
 implementation

---
 src/elvis_config.erl  | 190 ++++++++++++++++++++++++++----------------
 src/elvis_core.erl    |   2 -
 src/elvis_ruleset.erl |  62 +++++++++-----
 src/elvis_utils.erl   |  14 ++++
 4 files changed, 172 insertions(+), 96 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index ed67b858..ddcaf599 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -23,11 +23,26 @@
 %%% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-load_elvis(AppConfig) ->
-    ElvisConfig = proplists:get_value(elvis, AppConfig, default(elvis)),
-    elvis_ruleset:set_rulesets(proplists:get_value(rulesets, ElvisConfig, default(rulesets))),
+fetch_elvis_config(AppConfig) ->
+    ElvisConfig = from_static(elvis, {app, AppConfig}),
+    elvis_ruleset:load(from_static(rulesets, {elvis, ElvisConfig})),
     ElvisConfig.
 
+from_static(Key, {Type, Config}) ->
+    elvis_utils:output(debug, "fetching key ~p from ~p config.", [Key, Type]),
+    case proplists:get_value(Key, Config) of
+        undefined ->
+            elvis_utils:output(
+                debug, "no value for config. key ~p found in ~p config.; going with default", [
+                    Key, Type
+                ]
+            ),
+            default(Key);
+        Value ->
+            elvis_utils:output(debug, "value for config. key ~p found in ~p config.", [Key, Type]),
+            Value
+    end.
+
 config() ->
     for(config).
 
@@ -46,71 +61,98 @@ parallel() ->
 default(Key) ->
     case application:get_env(elvis_core, Key) of
         undefined ->
+            elvis_utils:output(
+                debug,
+                "no value for config. key ~p found in application env.; going with default",
+                [Key]
+            ),
             default_for(Key);
         {ok, Value} ->
+            elvis_utils:output(debug, "value for config. key ~p found in application env.", [Key]),
             Value
     end.
 
 for(Key) ->
+    ElvisDefault = default_for(elvis),
     AppConfig =
-        case consult_elvis_config(default) of
-            [] ->
-                consult_rebar_config(default);
+        case consult_elvis_config("elvis.config") of
+            ElvisDefault ->
+                % This might happen whether we fail to parse the fail or it actually is []
+                elvis_utils:output(
+                    debug, "elvis.config unusable; falling back to rebar.config", []
+                ),
+                consult_rebar_config("rebar.config");
             AppConfig0 ->
                 AppConfig0
         end,
-    TopLevelCfg = load_elvis(AppConfig),
-    proplists:get_value(Key, TopLevelCfg, default(Key)).
-
-consult_elvis_config(File0) ->
-    File =
-        case File0 of
-            default ->
-                "elvis.config";
-            _ ->
-                File0
-        end,
+    ElvisConfig = fetch_elvis_config(AppConfig),
+    from_static(Key, {elvis, ElvisConfig}).
+
+consult_elvis_config(File) ->
     case file:consult(File) of
         {ok, [AppConfig]} ->
+            elvis_utils:output(debug, "elvis.config usable; using it", []),
             AppConfig;
         _ ->
-            []
+            elvis_utils:output(debug, "elvis.config unusable", []),
+            default_for(elvis)
     end.
 
-consult_rebar_config(File0) ->
-    File =
-        case File0 of
-            default ->
-                "rebar.config";
-            _ ->
-                File0
-        end,
+consult_rebar_config(File) ->
     case file:consult(File) of
         {ok, AppConfig0} ->
+            elvis_utils:output(debug, "rebar.config usable; using it", []),
             AppConfig0;
         _ ->
-            []
+            elvis_utils:output(debug, "rebar.config unusable", []),
+            default_for(elvis)
     end.
 
 from_rebar(File) ->
     RebarConfig = consult_rebar_config(File),
-    TopLevelCfg = load_elvis(RebarConfig),
-    Key = config,
-    proplists:get_value(Key, TopLevelCfg, default(Key)).
+    ElvisConfig = fetch_elvis_config(RebarConfig),
+    from_static(config, {elvis, ElvisConfig}).
 
 from_file(File) ->
     FileConfig = consult_elvis_config(File),
-    TopLevelCfg = load_elvis(FileConfig),
-    Key = config,
-    proplists:get_value(Key, TopLevelCfg, default(Key)).
-
-default_for(elvis) -> [];
-default_for(config) -> [];
-default_for(output_format) -> colors;
-default_for(verbose) -> false;
-default_for(no_output) -> false;
-default_for(parallel) -> 1;
-default_for(rulesets) -> #{}.
+    ElvisConfig = fetch_elvis_config(FileConfig),
+    from_static(config, {elvis, ElvisConfig}).
+
+default_for(elvis) ->
+    [];
+default_for(config) ->
+    [
+        #{
+            dirs => ["apps/*/src/**", "src/**"],
+            filter => "*.erl",
+            ruleset => erl_files
+        },
+        #{
+            dirs => ["."],
+            filter => "rebar.config",
+            ruleset => rebar_config
+        },
+        #{
+            dirs => ["."],
+            filter => ".gitignore",
+            ruleset => gitignore
+        },
+        #{
+            dirs => ["."],
+            filter => "elvis.config",
+            ruleset => elvis_config
+        }
+    ];
+default_for(output_format) ->
+    colors;
+default_for(verbose) ->
+    false;
+default_for(no_output) ->
+    false;
+default_for(parallel) ->
+    1;
+default_for(rulesets) ->
+    #{}.
 
 -spec validate(Config :: [t()]) -> [validation_error()].
 validate([]) ->
@@ -344,35 +386,37 @@ is_rule_override(Rule, UserRules) ->
         UserRules
     ).
 
-flag_validated(Option) ->
-    Table = table(),
-    _ = create_table(Table),
-    Obj = validated_flag(Option),
-    ets:insert(Table, Obj).
-
-is_validated(Option) ->
-    Table = table(),
-    case table_exists(Table) of
-        false ->
-            false;
-        _ ->
-            Obj = validated_flag(Option),
-            ets:lookup(Table, Option) =:= [Obj]
-    end.
-
-validated_flag(Option) ->
-    {Option, validated}.
-
-create_table(Table) ->
-    case table_exists(Table) of
-        false ->
-            _ = ets:new(Table, [public, named_table]);
-        _ ->
-            ok
-    end.
-
-table() ->
-    ?MODULE.
-
-table_exists(Table) ->
-    ets:info(Table) =/= undefined.
+%flag_validated(Option) ->
+%    Table = table(),
+%    _ = create_table(Table),
+%    Obj = validated_flag(Option),
+%    ets:insert(Table, Obj).
+%
+%is_validated(Option) ->
+%    Table = table(),
+%    case table_exists(Table) of
+%        false ->
+%            false;
+%        _ ->
+%            Obj = validated_flag(Option),
+%            ets:lookup(Table, Option) =:= [Obj]
+%    end.
+%
+%validated_flag(Option) ->
+%    {Option, validated}.
+%
+%create_table(Table) ->
+%    case table_exists(Table) of
+%        false ->
+%            _ = ets:new(Table, [public, named_table]);
+%        _ ->
+%            ok
+%    end.
+%
+%table() ->
+%    ?MODULE.
+%
+%table_exists(Table) ->
+%    ets:info(Table) =/= undefined.
+%
+%-spec default_config() -> [t()].
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index cee64042..9018edff 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -33,7 +33,6 @@ start() ->
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
-    ok = elvis_config:validate(ElvisConfig),
     Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
     lists:foldl(fun combine_results/2, ok, Results).
 
@@ -44,7 +43,6 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
-    elvis_config:validate(ElvisConfig),
     Dirname = filename:dirname(Path),
     Filename = filename:basename(Path),
     File =
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index c201fa45..8761e479 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -2,18 +2,28 @@
 
 -format(#{inline_items => none}).
 
--export([rules/1, set_rulesets/1]).
-
--spec set_rulesets(#{atom() => list()}) -> ok.
-set_rulesets(Rulesets) ->
-    Tid = ensure_clean_table(),
-    lists:foreach(
-        fun({Ruleset, NSNameDefs}) ->
-            Rules = [elvis_rule:from_tuple(NSNameDef) || NSNameDef <- NSNameDefs],
-            true = ets:insert(Tid, {Ruleset, Rules})
-        end,
-        maps:to_list(Rulesets)
-    ).
+-export([rules/1, load/1]).
+
+-ifdef(TEST).
+-export([drop_custom/0]).
+-endif.
+
+-spec load(#{atom() => list()}) -> ok.
+load(Rulesets) ->
+    {Existed, Tid} = ensure_table(),
+    case Existed of
+        false ->
+            elvis_utils:output(debug, "loading custom rulesets into state", []),
+            lists:foreach(
+                fun({Ruleset, NSNameDefs}) ->
+                    Rules = [elvis_rule:from_tuple(NSNameDef) || NSNameDef <- NSNameDefs],
+                    true = ets:insert(Tid, {Ruleset, Rules})
+                end,
+                maps:to_list(Rulesets)
+            );
+        true ->
+            ok
+    end.
 
 -spec rules(Group :: atom()) -> [elvis_rule:t()].
 rules(gitignore) ->
@@ -35,22 +45,32 @@ rules(rebar_config) ->
 rules(erl_files_test) ->
     erl_files_test_rules();
 rules(Group) ->
-    try
-        ets:lookup_element(?MODULE, Group, 2)
-    catch
-        error:badarg ->
+    Table = table(),
+    case ets:lookup(Table, Group) of
+        [{Group, Rules}] ->
+            Rules;
+        _ ->
             []
     end.
 
-ensure_clean_table() ->
-    case ets:info(?MODULE) of
+ensure_table() ->
+    Table = table(),
+    case ets:info(Table) of
         undefined ->
-            ets:new(?MODULE, [set, named_table, {keypos, 1}, public]);
+            {false, ets:new(Table, [set, named_table, {keypos, 1}, public])};
         _ ->
-            true = ets:delete_all_objects(?MODULE),
-            ?MODULE
+            {true, Table}
     end.
 
+table() ->
+    ?MODULE.
+
+-ifdef(TEST).
+drop_custom() ->
+    Table = table(),
+    ets:delete(Table).
+-endif.
+
 gitignore_rules() ->
     [
         elvis_rule:new(elvis_gitignore, forbidden_patterns),
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index ad6803a1..050f033c 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -6,6 +6,8 @@
 -export([erlang_halt/1, to_str/1, split_all_lines/1, split_all_lines/2]).
 %% Output
 -export([info/2, notice/2, error/2, error_prn/2, warn_prn/2]).
+%% rebar3
+-export([output/3, abort/2]).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Public
@@ -111,3 +113,15 @@ escape_format_str(String) ->
     Result = re:replace(Binary, "[^~]~", "~~", [global]),
     ResultBin = iolist_to_binary(Result),
     binary_to_list(ResultBin).
+
+-dialyzer({nowarn_function, output/3}).
+-spec output(debug | info, Format :: io:format(), Data :: [term()]) -> ok.
+output(debug, Format, Data) ->
+    rebar_api:debug("Elvis: " ++ Format, Data);
+output(info, Format, Data) ->
+    rebar_api:info("Elvis: " ++ Format, Data).
+
+-dialyzer({nowarn_function, abort/2}).
+-spec abort(Format :: io:format(), Data :: [term()]) -> no_return().
+abort(Format, Data) ->
+    rebar_api:abort("Elvis: " ++ Format, [Data]).

From 2f5b2b734fec71426460fc4729a894a38acc71ca Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 18:08:11 +0100
Subject: [PATCH 07/67] Doc. it for consumers

---
 src/elvis_core.erl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 9018edff..5a8af73f 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -30,6 +30,8 @@ start() ->
     {ok, _} = application:ensure_all_started(elvis_core),
     ok.
 
+%% In this context, `throw` means an error, e.g., validation or internal, not an actual
+%% call to `erlang:throw/1`.
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
@@ -70,6 +72,8 @@ rock_this(Path, ElvisConfig) ->
             elvis_result_status(Results)
     end.
 
+%% In this context, `throw` means an error, e.g., validation or internal, not an actual
+%% call to `erlang:throw/1`.
 -spec do_parallel_rock(elvis_config:t()) ->
     ok
     | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.

From 1658690a8a411c9251828cd01f1e2584520c17ac Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 18:08:33 +0100
Subject: [PATCH 08/67] Prepare for further validation

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index ddcaf599..232eb5b5 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -169,7 +169,7 @@ do_validate(RuleGroup) ->
         ok ?= maybe_invalid_rules(RuleGroup)
     else
         {error, Error} ->
-            throw({invalid_config, Error})
+            {error, {invalid_config, Error}}
     end.
 
 maybe_missing_dirs(RuleGroup) ->

From 16e475b811b54cfae81f4a5b1f332d5c3dd2feb4 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 22:44:16 +0100
Subject: [PATCH 09/67] Trim to useful API

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 232eb5b5..15db396f 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -2,7 +2,7 @@
 
 -feature(maybe_expr, enable).
 
--export([from_rebar/1, from_file/1, validate/1]).
+-export([from_rebar/1, from_file/1]).
 %% Geters
 -export([dirs/1, ignore/1, filter/1, files/1, rules/1]).
 %% Files

From d11c2f89aefb9e811a406f896b55933047784fcf Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 22:44:32 +0100
Subject: [PATCH 10/67] Doc. it a little better

---
 src/elvis_config.erl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 15db396f..8b816fea 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -13,6 +13,7 @@
 %% Options
 -export([config/0, output_format/0, verbose/0, no_output/0, parallel/0]).
 
+% Corresponds to the 'config' key.
 -type t() :: map().
 -export_type([t/0]).
 

From 65e98c5e7868c499008ad8ba50792a38bd2df69f Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 22:45:19 +0100
Subject: [PATCH 11/67] Export used type

---
 src/elvis_config.erl | 42 +++++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 8b816fea..a00280d2 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -17,6 +17,9 @@
 -type t() :: map().
 -export_type([t/0]).
 
+-type elvis() :: proplists:proplist().
+-export_type([elvis/0]).
+
 -type validation_error() :: empty_config.
 -export_type([validation_error/0]).
 
@@ -27,7 +30,12 @@
 fetch_elvis_config(AppConfig) ->
     ElvisConfig = from_static(elvis, {app, AppConfig}),
     elvis_ruleset:load(from_static(rulesets, {elvis, ElvisConfig})),
-    ElvisConfig.
+    case validate(elvis) of
+        {error, _Errors} = E ->
+            E;
+        ok ->
+            {ok, ElvisConfig}
+    end.
 
 from_static(Key, {Type, Config}) ->
     elvis_utils:output(debug, "fetching key ~p from ~p config.", [Key, Type]),
@@ -74,10 +82,10 @@ default(Key) ->
     end.
 
 for(Key) ->
-    ElvisDefault = default_for(elvis),
+    AppDefault = default_for(app),
     AppConfig =
         case consult_elvis_config("elvis.config") of
-            ElvisDefault ->
+            AppDefault ->
                 % This might happen whether we fail to parse the fail or it actually is []
                 elvis_utils:output(
                     debug, "elvis.config unusable; falling back to rebar.config", []
@@ -86,7 +94,8 @@ for(Key) ->
             AppConfig0 ->
                 AppConfig0
         end,
-    ElvisConfig = fetch_elvis_config(AppConfig),
+    % If we got this far, the config. is valid...
+    {ok, ElvisConfig} = fetch_elvis_config(AppConfig),
     from_static(Key, {elvis, ElvisConfig}).
 
 consult_elvis_config(File) ->
@@ -96,7 +105,7 @@ consult_elvis_config(File) ->
             AppConfig;
         _ ->
             elvis_utils:output(debug, "elvis.config unusable", []),
-            default_for(elvis)
+            default_for(app)
     end.
 
 consult_rebar_config(File) ->
@@ -106,19 +115,30 @@ consult_rebar_config(File) ->
             AppConfig0;
         _ ->
             elvis_utils:output(debug, "rebar.config unusable", []),
-            default_for(elvis)
+            default_for(app)
     end.
 
+-spec from_rebar(string()) -> {ok, elvis()} | {error, [validation_error()]}.
 from_rebar(File) ->
-    RebarConfig = consult_rebar_config(File),
-    ElvisConfig = fetch_elvis_config(RebarConfig),
-    from_static(config, {elvis, ElvisConfig}).
+    AppConfig = consult_rebar_config(File),
+    fetch_elvis_config_from(AppConfig).
 
+-spec from_file(string()) -> {ok, elvis()} | {error, [validation_error()]}.
 from_file(File) ->
     FileConfig = consult_elvis_config(File),
-    ElvisConfig = fetch_elvis_config(FileConfig),
-    from_static(config, {elvis, ElvisConfig}).
+    fetch_elvis_config_from(FileConfig).
+
+fetch_elvis_config_from(AppConfig) ->
+    case fetch_elvis_config(AppConfig) of
+        {error, _Errors} = E ->
+            E;
+        {ok, ElvisConfig} ->
+            {ok, from_static(config, {elvis, ElvisConfig})}
+    end.
 
+default_for(app) ->
+    % This is the top-level element, before 'elvis'
+    [];
 default_for(elvis) ->
     [];
 default_for(config) ->

From 4183e7466681c1d13762de040c48c7170c5ac081 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 22:45:51 +0100
Subject: [PATCH 12/67] Respect current constraints

---
 src/elvis_utils.erl | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 050f033c..64cd7abf 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -115,13 +115,36 @@ escape_format_str(String) ->
     binary_to_list(ResultBin).
 
 -dialyzer({nowarn_function, output/3}).
--spec output(debug | info, Format :: io:format(), Data :: [term()]) -> ok.
+-spec output(debug | info | error, Format :: io:format(), Data :: [term()]) -> ok.
 output(debug, Format, Data) ->
-    rebar_api:debug("Elvis: " ++ Format, Data);
+    case erlang:function_exported(rebar_api, debug, 2) of
+        true ->
+            rebar_api:debug("Elvis: " ++ Format, Data);
+        false ->
+            ok
+    end;
 output(info, Format, Data) ->
-    rebar_api:info("Elvis: " ++ Format, Data).
+    case erlang:function_exported(rebar_api, info, 2) of
+        true ->
+            rebar_api:info("Elvis: " ++ Format, Data);
+        false ->
+            ok
+    end;
+output(error, Format, Data) ->
+    case erlang:function_exported(rebar_api, error, 2) of
+        true ->
+            rebar_api:error("Elvis: " ++ Format, Data);
+        false ->
+            ok
+    end.
 
 -dialyzer({nowarn_function, abort/2}).
 -spec abort(Format :: io:format(), Data :: [term()]) -> no_return().
 abort(Format, Data) ->
-    rebar_api:abort("Elvis: " ++ Format, [Data]).
+    case erlang:function_exported(rebar_api, abort, 2) of
+        true ->
+            rebar_api:abort("Elvis: " ++ Format, [Data]);
+        false ->
+            output(error, Format, Data),
+            throw(elvis_abort)
+    end.

From 94bf88b6b778d240a33ea86ce996fa2057617071 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 10 Jul 2025 22:52:15 +0100
Subject: [PATCH 13/67] Adapt to current API

---
 src/elvis_config.erl  |  2 +-
 src/elvis_core.erl    |  2 ++
 src/elvis_ruleset.erl | 15 ++++++++++++---
 test/elvis_SUITE.erl  | 14 +++++++-------
 4 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index a00280d2..f569bf24 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -29,7 +29,7 @@
 
 fetch_elvis_config(AppConfig) ->
     ElvisConfig = from_static(elvis, {app, AppConfig}),
-    elvis_ruleset:load(from_static(rulesets, {elvis, ElvisConfig})),
+    elvis_ruleset:load_custom(from_static(rulesets, {elvis, ElvisConfig})),
     case validate(elvis) of
         {error, _Errors} = E ->
             E;
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 5a8af73f..2843aefc 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -35,6 +35,7 @@ start() ->
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
+    elvis_ruleset:dump_custom(),
     Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
     lists:foldl(fun combine_results/2, ok, Results).
 
@@ -45,6 +46,7 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
+    elvis_ruleset:dump_custom(),
     Dirname = filename:dirname(Path),
     Filename = filename:basename(Path),
     File =
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 8761e479..5d979413 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -2,14 +2,14 @@
 
 -format(#{inline_items => none}).
 
--export([rules/1, load/1]).
+-export([rules/1, load_custom/1, dump_custom/0]).
 
 -ifdef(TEST).
 -export([drop_custom/0]).
 -endif.
 
--spec load(#{atom() => list()}) -> ok.
-load(Rulesets) ->
+-spec load_custom(#{atom() => list()}) -> ok.
+load_custom(Rulesets) ->
     {Existed, Tid} = ensure_table(),
     case Existed of
         false ->
@@ -25,6 +25,15 @@ load(Rulesets) ->
             ok
     end.
 
+dump_custom() ->
+    Table = table(),
+    case ets:info(Table) of
+        undefined ->
+            ok;
+        _ ->
+            ets:delete(Table)
+    end.
+
 -spec rules(Group :: atom()) -> [elvis_rule:t()].
 rules(gitignore) ->
     gitignore_rules();
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 6a410097..028bade7 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -111,7 +111,7 @@ rock_with_list_config(_Config) ->
 
 rock_with_file_config(_Config) ->
     ConfigPath = "../../config/elvis.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
+    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected =
         "# \\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++ "examples/.*\\.erl.*FAIL",
@@ -120,7 +120,7 @@ rock_with_file_config(_Config) ->
 
 rock_with_rebar_default_config(_Config) ->
     {ok, _} = file:copy("../../config/rebar.config", "rebar.config"),
-    ElvisConfig = elvis_config:from_rebar("rebar.config"),
+    {ok, ElvisConfig} = elvis_config:from_rebar("rebar.config"),
     [#{name := line_length}] =
         try
             {fail, Results} = elvis_core:rock(ElvisConfig),
@@ -205,7 +205,7 @@ rock_with_errors_has_output(_Config) ->
 
 rock_without_errors_has_no_output(_Config) ->
     ConfigPath = "../../config/test.pass.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
+    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Output = get_output(Fun),
     %% This is related to the test case `rock_with_non_parsable_file`,
@@ -318,7 +318,7 @@ rock_this_skipping_files(_Config) ->
     [File] = elvis_file:find_files(Dirs, "small.erl"),
     Path = elvis_file:path(File),
     ConfigPath = "../../config/elvis-test-pa.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
+    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
     ok = elvis_core:rock_this(Path, ElvisConfig),
     0 = meck:num_calls(elvis_file, load_file_data, '_'),
     meck:unload(elvis_file),
@@ -337,7 +337,7 @@ rock_this_not_skipping_files(_Config) ->
 
 rock_with_umbrella_apps(_Config) ->
     ElvisUmbrellaConfigFile = "../../config/elvis-umbrella.config",
-    ElvisConfig = elvis_config:from_file(ElvisUmbrellaConfigFile),
+    {ok, ElvisConfig} = elvis_config:from_file(ElvisUmbrellaConfigFile),
     {fail, [
         #{file := "../../_build/test/lib/elvis_core/test/dirs/test/dir_test.erl"},
         #{file := "../../_build/test/lib/elvis_core/test/dirs/src/dirs_src.erl"},
@@ -384,7 +384,7 @@ rock_with_invalid_rules(_Config) ->
 
 custom_ruleset(_Config) ->
     ConfigPath = "../../config/elvis-test-custom-ruleset.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
+    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
     NoTabs = elvis_rule:new(elvis_text_style, no_tabs),
     [[NoTabs]] = elvis_config:rules(ElvisConfig),
 
@@ -397,7 +397,7 @@ custom_ruleset(_Config) ->
 
 hrl_ruleset(_Config) ->
     ConfigPath = "../../config/elvis-test-hrl-files.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
+    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
     {fail, [
         #{file := "../../_build/test/lib/elvis_core/test/examples/test_good.hrl", rules := []},
         #{

From bf33731766a1d58cbb7b3ef4d5ff365b576141f9 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sun, 13 Jul 2025 17:58:50 +0100
Subject: [PATCH 14/67] Expect test results to remain the same (adapt to
 current implementation)

---
 test/elvis_SUITE.erl | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 028bade7..6a410097 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -111,7 +111,7 @@ rock_with_list_config(_Config) ->
 
 rock_with_file_config(_Config) ->
     ConfigPath = "../../config/elvis.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
+    ElvisConfig = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected =
         "# \\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++ "examples/.*\\.erl.*FAIL",
@@ -120,7 +120,7 @@ rock_with_file_config(_Config) ->
 
 rock_with_rebar_default_config(_Config) ->
     {ok, _} = file:copy("../../config/rebar.config", "rebar.config"),
-    {ok, ElvisConfig} = elvis_config:from_rebar("rebar.config"),
+    ElvisConfig = elvis_config:from_rebar("rebar.config"),
     [#{name := line_length}] =
         try
             {fail, Results} = elvis_core:rock(ElvisConfig),
@@ -205,7 +205,7 @@ rock_with_errors_has_output(_Config) ->
 
 rock_without_errors_has_no_output(_Config) ->
     ConfigPath = "../../config/test.pass.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
+    ElvisConfig = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Output = get_output(Fun),
     %% This is related to the test case `rock_with_non_parsable_file`,
@@ -318,7 +318,7 @@ rock_this_skipping_files(_Config) ->
     [File] = elvis_file:find_files(Dirs, "small.erl"),
     Path = elvis_file:path(File),
     ConfigPath = "../../config/elvis-test-pa.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
+    ElvisConfig = elvis_config:from_file(ConfigPath),
     ok = elvis_core:rock_this(Path, ElvisConfig),
     0 = meck:num_calls(elvis_file, load_file_data, '_'),
     meck:unload(elvis_file),
@@ -337,7 +337,7 @@ rock_this_not_skipping_files(_Config) ->
 
 rock_with_umbrella_apps(_Config) ->
     ElvisUmbrellaConfigFile = "../../config/elvis-umbrella.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ElvisUmbrellaConfigFile),
+    ElvisConfig = elvis_config:from_file(ElvisUmbrellaConfigFile),
     {fail, [
         #{file := "../../_build/test/lib/elvis_core/test/dirs/test/dir_test.erl"},
         #{file := "../../_build/test/lib/elvis_core/test/dirs/src/dirs_src.erl"},
@@ -384,7 +384,7 @@ rock_with_invalid_rules(_Config) ->
 
 custom_ruleset(_Config) ->
     ConfigPath = "../../config/elvis-test-custom-ruleset.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
+    ElvisConfig = elvis_config:from_file(ConfigPath),
     NoTabs = elvis_rule:new(elvis_text_style, no_tabs),
     [[NoTabs]] = elvis_config:rules(ElvisConfig),
 
@@ -397,7 +397,7 @@ custom_ruleset(_Config) ->
 
 hrl_ruleset(_Config) ->
     ConfigPath = "../../config/elvis-test-hrl-files.config",
-    {ok, ElvisConfig} = elvis_config:from_file(ConfigPath),
+    ElvisConfig = elvis_config:from_file(ConfigPath),
     {fail, [
         #{file := "../../_build/test/lib/elvis_core/test/examples/test_good.hrl", rules := []},
         #{

From 33926906b37d66757d7f3b821ed1543db42757c0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sun, 13 Jul 2025 17:59:15 +0100
Subject: [PATCH 15/67] Allow elvis_rule to validate an input 2/3-tuple

---
 src/elvis_rule.erl | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/elvis_rule.erl b/src/elvis_rule.erl
index d00394df..d90425ab 100644
--- a/src/elvis_rule.erl
+++ b/src/elvis_rule.erl
@@ -3,6 +3,7 @@
 -export([
     new/2, new/3,
     from_tuple/1,
+    is_valid_from_tuple/1,
     ns/1,
     name/1,
     def/1,
@@ -49,7 +50,7 @@ new(NS, Name, Def) ->
         ignores = maps:get(ignore, Def, [])
     }.
 
--spec from_tuple(Rule | NSName | NSNameDef) -> t() when
+-spec from_tuple(Rule | NSName | NSNameDef) -> t() | invalid_tuple when
     Rule :: t(),
     NSName :: {NS :: module(), Name :: atom()},
     NSNameDef :: {NS :: module(), Name :: atom(), Def :: disable | map()}.
@@ -57,7 +58,7 @@ from_tuple(Rule) when is_record(Rule, rule) ->
     Rule;
 from_tuple({NS, Name}) ->
     from_tuple({NS, Name, #{}});
-from_tuple({NS, Name, Def0}) ->
+from_tuple({NS, Name, Def0}) when is_map(Def0) orelse Def0 =:= disable ->
     {Def, Disable} =
         case Def0 of
             disable ->
@@ -71,6 +72,36 @@ from_tuple({NS, Name, Def0}) ->
             disable(Rule);
         false ->
             Rule
+    end;
+from_tuple(_) ->
+    invalid_tuple.
+
+is_valid_from_tuple(Tuple) ->
+    case from_tuple(Tuple) of
+        invalid_tuple ->
+            {false, "got an invalid tuple (is def. a map or 'disable'?)."};
+        Rule ->
+            NS = ns(Rule),
+            case is_atom(NS) of
+                true ->
+                    _ = code:ensure_loaded(NS);
+                false ->
+                    ok
+            end,
+            Name = name(Rule),
+            ArityForExecute = 2,
+            case
+                is_atom(NS) andalso is_atom(Name) andalso
+                    erlang:function_exported(NS, Name, ArityForExecute)
+            of
+                true ->
+                    {true, Rule};
+                _ ->
+                    {false,
+                        io_lib:format("got an unexpected/invalid ~p:~p/~p combo.", [
+                            NS, Name, ArityForExecute
+                        ])}
+            end
     end.
 
 -spec ns(t()) -> module().

From 49018f60b9d5d8bc6e56846569d0304be31d80fe Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sun, 13 Jul 2025 18:55:22 +0100
Subject: [PATCH 16/67] Allow elvis_rule to validate an input ignorable

---
 src/elvis_rule.erl | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/src/elvis_rule.erl b/src/elvis_rule.erl
index d90425ab..e03bf122 100644
--- a/src/elvis_rule.erl
+++ b/src/elvis_rule.erl
@@ -4,6 +4,7 @@
     new/2, new/3,
     from_tuple/1,
     is_valid_from_tuple/1,
+    is_ignorable/1,
     ns/1,
     name/1,
     def/1,
@@ -104,6 +105,42 @@ is_valid_from_tuple(Tuple) ->
             end
     end.
 
+% Module - invalid type
+is_ignorable(Module) when not is_tuple(Module) andalso not is_atom(Module) ->
+    false;
+% Module - test if valid
+is_ignorable(Module) when is_atom(Module) ->
+    case code:ensure_loaded(Module) of
+        {module, _} ->
+            true;
+        _ ->
+            false
+    end;
+% {Module, Function} - invalid type
+is_ignorable({Module, Function}) when not is_atom(Module) orelse not is_atom(Function) ->
+    false;
+% {Module, Function} - test if valid
+is_ignorable({Module, Function}) ->
+    case is_ignorable(Module) of
+        true ->
+            Exports = Module:module_info(exports),
+            proplists:get_value(Function, Exports) =/= undefined;
+        false ->
+            false
+    end;
+% {Module, Function, Arity} - invalid type
+is_ignorable({Module, Function, Arity}) when not is_atom(Module) orelse not is_atom(Function) orelse not is_integer(Arity) orelse Arity < 0 ->
+    false;
+% {Module, Function, Arity} - test if valid
+is_ignorable({Module, Function, Arity}) ->
+    case is_ignorable(Module) of
+        true ->
+            Exports = Module:module_info(exports),
+            proplists:get_value(Function, Exports) =:= Arity;
+        false ->
+            false
+    end.
+
 -spec ns(t()) -> module().
 ns(Rule) ->
     Rule#rule.ns.

From 85517d6cbdb237f22bac12e2fb69dea9fbbb887b Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sun, 13 Jul 2025 18:55:38 +0100
Subject: [PATCH 17/67] Have notion of definition belong to appropriate
 namespace

---
 src/elvis_ruleset.erl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 5d979413..4ea57f92 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -2,7 +2,7 @@
 
 -format(#{inline_items => none}).
 
--export([rules/1, load_custom/1, dump_custom/0]).
+-export([rules/1, load_custom/1, dump_custom/0, is_defined/1]).
 
 -ifdef(TEST).
 -export([drop_custom/0]).
@@ -34,6 +34,9 @@ dump_custom() ->
             ets:delete(Table)
     end.
 
+is_defined(Ruleset) ->
+    elvis_ruleset:rules(Ruleset) =/= [].
+
 -spec rules(Group :: atom()) -> [elvis_rule:t()].
 rules(gitignore) ->
     gitignore_rules();

From 642f85d69bdb0c654241a584cef1638f084a0389 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Sun, 13 Jul 2025 22:02:56 +0100
Subject: [PATCH 18/67] Allow for further config. validation

---
 src/elvis_rule.erl | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/src/elvis_rule.erl b/src/elvis_rule.erl
index e03bf122..1445b632 100644
--- a/src/elvis_rule.erl
+++ b/src/elvis_rule.erl
@@ -15,6 +15,7 @@
     execute/2,
     option/2,
     defmap/1,
+    defkeys/1,
     ignorable/1,
     same/2
 ]).
@@ -83,12 +84,7 @@ is_valid_from_tuple(Tuple) ->
             {false, "got an invalid tuple (is def. a map or 'disable'?)."};
         Rule ->
             NS = ns(Rule),
-            case is_atom(NS) of
-                true ->
-                    _ = code:ensure_loaded(NS);
-                false ->
-                    ok
-            end,
+            _ = maybe_ensure_loaded(NS),
             Name = name(Rule),
             ArityForExecute = 2,
             case
@@ -105,12 +101,17 @@ is_valid_from_tuple(Tuple) ->
             end
     end.
 
+maybe_ensure_loaded(NS) when not is_atom(NS) ->
+    ok;
+maybe_ensure_loaded(NS) ->
+    code:ensure_loaded(NS).
+
 % Module - invalid type
 is_ignorable(Module) when not is_tuple(Module) andalso not is_atom(Module) ->
     false;
 % Module - test if valid
 is_ignorable(Module) when is_atom(Module) ->
-    case code:ensure_loaded(Module) of
+    case maybe_ensure_loaded(Module) of
         {module, _} ->
             true;
         _ ->
@@ -129,7 +130,9 @@ is_ignorable({Module, Function}) ->
             false
     end;
 % {Module, Function, Arity} - invalid type
-is_ignorable({Module, Function, Arity}) when not is_atom(Module) orelse not is_atom(Function) orelse not is_integer(Arity) orelse Arity < 0 ->
+is_ignorable({Module, Function, Arity}) when
+    not is_atom(Module) orelse not is_atom(Function) orelse not is_integer(Arity) orelse Arity < 0
+->
     false;
 % {Module, Function, Arity} - test if valid
 is_ignorable({Module, Function, Arity}) ->
@@ -206,12 +209,24 @@ default(Rule) ->
 
 -spec default(NS :: module(), Name :: atom()) -> def().
 default(NS, Name) ->
-    NS:default(Name).
+    _ = maybe_ensure_loaded(NS),
+    ArityForDefault = 1,
+    case erlang:function_exported(NS, default, ArityForDefault) of
+        false ->
+            #{};
+        true ->
+            NS:default(Name)
+    end.
 
 -spec defmap(map()) -> def().
 defmap(Map) ->
     Map.
 
+-spec defkeys(t()) -> [atom()].
+defkeys(Rule) ->
+    Def = def(Rule),
+    maps:keys(Def).
+
 -spec ignorable(module() | {module(), atom()} | {module(), atom(), arity()}) -> ignorable().
 ignorable(Ignorable) ->
     Ignorable.

From 27005e610d17c44f16031b0a29b75a6216ee6006 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 14 Jul 2025 22:12:26 +0100
Subject: [PATCH 19/67] Validate the configuration

---
 elvis.config         |  14 +-
 src/elvis_code.erl   |   2 +-
 src/elvis_config.erl | 556 ++++++++++++++++++++++++++++++++-----------
 src/elvis_core.erl   |   6 +-
 src/elvis_result.erl |  13 +-
 src/elvis_utils.erl  |  27 +--
 6 files changed, 447 insertions(+), 171 deletions(-)

diff --git a/elvis.config b/elvis.config
index e90c5bed..310c50f1 100644
--- a/elvis.config
+++ b/elvis.config
@@ -7,7 +7,10 @@
                 rules =>
                     [
                         {elvis_style, no_invalid_dynamic_calls, #{
-                            ignore => [{elvis_core, rock_this, 2}]
+                            ignore => [
+                                {elvis_core, rock_this, 2},
+                                {elvis_config, check_rule_for_options, 2}
+                            ]
                         }},
                         {elvis_style, dont_repeat_yourself, #{min_complexity => 20}},
                         {elvis_style, no_debug_call, #{
@@ -17,7 +20,7 @@
                         {elvis_style, no_throw, disable},
                         {elvis_style, max_function_length, disable},
                         {elvis_style, max_function_clause_length, disable},
-                        {elvis_style, max_module_length, #{ignore => [elvis_style]}},
+                        {elvis_style, max_module_length, #{ignore => [elvis_style, elvis_config]}},
                         {elvis_style, no_common_caveats_call, #{
                             ignore => [
                                 {elvis_file, module, 1},
@@ -34,7 +37,9 @@
                 filter => "*.beam",
                 rules =>
                     [
-                        {elvis_style, no_invalid_dynamic_calls, #{ignore => [elvis_core]}},
+                        {elvis_style, no_invalid_dynamic_calls, #{
+                            ignore => [elvis_core, elvis_config]
+                        }},
                         {elvis_style, dont_repeat_yourself, #{min_complexity => 20}},
                         {elvis_style, no_debug_call, #{ignore => [elvis_result, elvis_utils]}},
                         {elvis_style, no_god_modules, #{ignore => [elvis_style]}},
@@ -65,6 +70,7 @@
                         {elvis_style, atom_naming_convention, #{ignore => [style_SUITE]}}
                     ]
             }
-        ]}
+        ]},
+        {no_output, true}
     ]}
 ].
diff --git a/src/elvis_code.erl b/src/elvis_code.erl
index 09c0701b..8eba2a45 100644
--- a/src/elvis_code.erl
+++ b/src/elvis_code.erl
@@ -186,6 +186,6 @@ print_node(#{type := Type} = Node, CurrentLevel) ->
     Indentation = lists:duplicate(CurrentLevel * 4, $\s),
     Content = ktn_code:content(Node),
 
-    ok = elvis_utils:info("~s - [~p] ~p~n", [Indentation, CurrentLevel, Type]),
+    ok = elvis_utils:output(info, "~s - [~p] ~p~n", [Indentation, CurrentLevel, Type]),
     _ = lists:map(fun(Child) -> print_node(Child, CurrentLevel + 1) end, Content),
     ok.
diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index f569bf24..c1c58c2c 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -20,22 +20,15 @@
 -type elvis() :: proplists:proplist().
 -export_type([elvis/0]).
 
--type validation_error() :: empty_config.
--export_type([validation_error/0]).
-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 fetch_elvis_config(AppConfig) ->
     ElvisConfig = from_static(elvis, {app, AppConfig}),
-    elvis_ruleset:load_custom(from_static(rulesets, {elvis, ElvisConfig})),
-    case validate(elvis) of
-        {error, _Errors} = E ->
-            E;
-        ok ->
-            {ok, ElvisConfig}
-    end.
+    _ = validate({elvis, ElvisConfig}),
+    _ = elvis_ruleset:load_custom(from_static(rulesets, {elvis, ElvisConfig})),
+    ElvisConfig.
 
 from_static(Key, {Type, Config}) ->
     elvis_utils:output(debug, "fetching key ~p from ~p config.", [Key, Type]),
@@ -95,7 +88,7 @@ for(Key) ->
                 AppConfig0
         end,
     % If we got this far, the config. is valid...
-    {ok, ElvisConfig} = fetch_elvis_config(AppConfig),
+    ElvisConfig = fetch_elvis_config(AppConfig),
     from_static(Key, {elvis, ElvisConfig}).
 
 consult_elvis_config(File) ->
@@ -118,23 +111,17 @@ consult_rebar_config(File) ->
             default_for(app)
     end.
 
--spec from_rebar(string()) -> {ok, elvis()} | {error, [validation_error()]}.
 from_rebar(File) ->
     AppConfig = consult_rebar_config(File),
     fetch_elvis_config_from(AppConfig).
 
--spec from_file(string()) -> {ok, elvis()} | {error, [validation_error()]}.
 from_file(File) ->
     FileConfig = consult_elvis_config(File),
     fetch_elvis_config_from(FileConfig).
 
 fetch_elvis_config_from(AppConfig) ->
-    case fetch_elvis_config(AppConfig) of
-        {error, _Errors} = E ->
-            E;
-        {ok, ElvisConfig} ->
-            {ok, from_static(config, {elvis, ElvisConfig})}
-    end.
+    ElvisConfig = fetch_elvis_config(AppConfig),
+    from_static(config, {elvis, ElvisConfig}).
 
 default_for(app) ->
     % This is the top-level element, before 'elvis'
@@ -144,10 +131,23 @@ default_for(elvis) ->
 default_for(config) ->
     [
         #{
-            dirs => ["apps/*/src/**", "src/**"],
+            dirs => [
+                "apps/**/src/**",
+                "src/**"
+            ],
             filter => "*.erl",
             ruleset => erl_files
         },
+        #{
+            dirs => [
+                "apps/**/src/**",
+                "src/**",
+                "apps/**/include/**",
+                "include/**"
+            ],
+            filter => "*.erl",
+            ruleset => hrl_files
+        },
         #{
             dirs => ["."],
             filter => "rebar.config",
@@ -157,11 +157,6 @@ default_for(config) ->
             dirs => ["."],
             filter => ".gitignore",
             ruleset => gitignore
-        },
-        #{
-            dirs => ["."],
-            filter => "elvis.config",
-            ruleset => elvis_config
         }
     ];
 default_for(output_format) ->
@@ -173,74 +168,18 @@ default_for(no_output) ->
 default_for(parallel) ->
     1;
 default_for(rulesets) ->
-    #{}.
-
--spec validate(Config :: [t()]) -> [validation_error()].
-validate([]) ->
-    [empty_config];
-validate(Config) ->
-    lists:foreach(fun do_validate/1, Config),
+    #{};
+default_for([config, dirs]) ->
+    [];
+default_for([config, filter]) ->
+    "";
+default_for([config, ignore]) ->
+    [];
+default_for([config, ruleset]) ->
+    undefined;
+default_for([config, rules]) ->
     [].
 
-do_validate(RuleGroup) ->
-    maybe
-        ok ?= maybe_missing_dirs(RuleGroup),
-        ok ?= maybe_missing_filter(RuleGroup),
-        ok ?= maybe_missing_rules(RuleGroup),
-        ok ?= maybe_invalid_rules(RuleGroup)
-    else
-        {error, Error} ->
-            {error, {invalid_config, Error}}
-    end.
-
-maybe_missing_dirs(RuleGroup) ->
-    maybe_boolean_wrapper(
-        not (maps:is_key(dirs, RuleGroup) andalso not maps:is_key(filter, RuleGroup)), missing_dir
-    ).
-
-maybe_missing_filter(RuleGroup) ->
-    maybe_boolean_wrapper(
-        maps:is_key(dirs, RuleGroup), missing_filter
-    ).
-
-maybe_missing_rules(RuleGroup) ->
-    maybe_boolean_wrapper(
-        maps:is_key(rules, RuleGroup) orelse maps:is_key(ruleset, RuleGroup), missing_rules
-    ).
-
-maybe_boolean_wrapper(true, _Flag) -> ok;
-maybe_boolean_wrapper(false, Flag) -> {error, Flag}.
-
-maybe_invalid_rules(#{rules := Rules}) ->
-    case invalid_rules(Rules) of
-        [] -> ok;
-        InvalidRules -> {error, {invalid_rules, InvalidRules}}
-    end;
-maybe_invalid_rules(_) ->
-    ok.
-
-invalid_rules(Rules) ->
-    lists:filtermap(fun is_invalid_rule/1, Rules).
-
-is_invalid_rule({NS, Rule, _}) ->
-    is_invalid_rule({NS, Rule});
-is_invalid_rule({NS, Rule}) ->
-    maybe
-        {module, NS} ?= code:ensure_loaded(NS),
-        ExportedRules = erlang:get_module_info(NS, exports),
-        case lists:keymember(Rule, 1, ExportedRules) of
-            false -> {true, {invalid_rule, {NS, Rule}}};
-            _ -> false
-        end
-    else
-        {error, _} ->
-            elvis_utils:warn_prn(
-                "Invalid module (~p) specified in elvis.config.~n",
-                [NS]
-            ),
-            {true, {invalid_rule, {NS, Rule}}}
-    end.
-
 -spec dirs(Config :: [t()] | t()) -> [string()].
 dirs(Config) when is_list(Config) ->
     lists:flatmap(fun dirs/1, Config);
@@ -303,22 +242,6 @@ resolve_files(RuleGroup, Files) ->
     Dirs = dirs(RuleGroup),
     Ignore = ignore(RuleGroup),
     FilteredFiles = elvis_file:filter_files(Files, Dirs, Filter, Ignore),
-    _ =
-        case FilteredFiles of
-            [] ->
-                Ruleset = maps:get(ruleset, RuleGroup, undefined),
-                Error =
-                    elvis_result:new(
-                        warn,
-                        "Searching for files in ~p, for ruleset ~p, "
-                        "with filter ~p, yielded none. "
-                        "Update your configuration",
-                        [Dirs, Ruleset, Filter]
-                    ),
-                ok = elvis_result:print_results([Error]);
-            _ ->
-                ok
-        end,
     RuleGroup#{files => FilteredFiles}.
 
 %% @doc Takes a configuration and finds all files according to its 'dirs'
@@ -407,37 +330,388 @@ is_rule_override(Rule, UserRules) ->
         UserRules
     ).
 
-%flag_validated(Option) ->
-%    Table = table(),
-%    _ = create_table(Table),
-%    Obj = validated_flag(Option),
-%    ets:insert(Table, Obj).
-%
-%is_validated(Option) ->
-%    Table = table(),
-%    case table_exists(Table) of
-%        false ->
-%            false;
-%        _ ->
-%            Obj = validated_flag(Option),
-%            ets:lookup(Table, Option) =:= [Obj]
-%    end.
-%
-%validated_flag(Option) ->
-%    {Option, validated}.
-%
-%create_table(Table) ->
-%    case table_exists(Table) of
-%        false ->
-%            _ = ets:new(Table, [public, named_table]);
-%        _ ->
-%            ok
-%    end.
-%
-%table() ->
-%    ?MODULE.
-%
-%table_exists(Table) ->
-%    ets:info(Table) =/= undefined.
-%
-%-spec default_config() -> [t()].
+validate({elvis = Option, ElvisConfig}) ->
+    case check_flag(validated(Option)) orelse check_flag(validation_started(Option)) of
+        true ->
+            ok;
+        false ->
+            do_validate({Option, ElvisConfig})
+    end.
+
+get_elvis_opt(OptName, ElvisConfig) ->
+    proplists:get_value(OptName, ElvisConfig, default_for(OptName)).
+
+do_validate({elvis = Option, ElvisConfig}) ->
+    maybe
+        ok = flag(validation_started(Option)),
+        ok ?= is_list("elvis", ElvisConfig),
+        ok ?=
+            proplist_keys_are_in("elvis", ElvisConfig, [
+                output_format, verbose, no_output, parallel, rulesets, config
+            ]),
+        OutputFormat = get_elvis_opt(output_format, ElvisConfig),
+        ok ?= is_one_of("elvis.output_format", OutputFormat, [colors, plain, parsable]),
+        Verbose = get_elvis_opt(verbose, ElvisConfig),
+        ok ?= is_boolean("elvis.verbose", Verbose),
+        NoOutput = get_elvis_opt(no_output, ElvisConfig),
+        ok ?= is_boolean("elvis.no_output", NoOutput),
+        Parallel = get_elvis_opt(parallel, ElvisConfig),
+        ok ?= is_pos_integer("elvis.parallel", Parallel),
+        Rulesets = get_elvis_opt(rulesets, ElvisConfig),
+        ok ?= is_valid_rulesets("elvis.rulesets", Rulesets),
+        Config = get_elvis_opt(config, ElvisConfig),
+        ok ?= is_valid_config("elvis.config", Rulesets, Config),
+        ok = flag(validated(Option))
+    else
+        {error, FormatData} ->
+            {Format, Data} =
+                case is_list(FormatData) of
+                    false ->
+                        FormatData;
+                    true ->
+                        % Get only first result, for now
+                        % If we wanna be smarter we need to start concatenating readable strings
+                        [{Format0, Data0} | _] = FormatData,
+                        {Format0, Data0}
+                end,
+            % on warnings_as_errors this'll throw an exception
+            %throw({invalid_config, io_lib:format(Format, Data)})
+            elvis_utils:output(warn, Format, Data)
+    end.
+
+is_list(What, List) ->
+    case is_list(List) of
+        true ->
+            ok;
+        _ ->
+            {error, {"~p is expected to be a list.", [What]}}
+    end.
+
+proplist_keys_are_in(What, List, Keys) ->
+    Filtered = [Element || {Element, _} <- List, not lists:member(Element, Keys)],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error, {"in ~p, the following keys are unknown: ~p.", [What, Filtered]}}
+    end.
+
+is_one_of(What, Value, Possibilities) ->
+    case lists:member(Value, Possibilities) of
+        true ->
+            ok;
+        _ ->
+            {error, {"~p is expected to be one of the following: ~p.", [What, Possibilities]}}
+    end.
+
+is_boolean(What, Value) ->
+    case is_boolean(Value) of
+        true ->
+            ok;
+        _ ->
+            {error, {"~p is expected to be a boolean.", [What]}}
+    end.
+
+is_pos_integer(What, Value) ->
+    case is_integer(Value) andalso Value > 0 of
+        true ->
+            ok;
+        _ ->
+            {error, {"~p is expected to be a positive integer.", [What]}}
+    end.
+
+is_valid_rulesets(What, Rulesets) ->
+    maybe
+        ok ?= is_map(What, Rulesets),
+        ok ?= all_map_keys_are_atoms(What, Rulesets),
+        ok ?= all_rulesets_have_valid_rules(What, Rulesets),
+        ok ?= no_rulesets_exist(What, Rulesets)
+    else
+        {error, FormatData} ->
+            {error, FormatData}
+    end.
+
+is_map(What, Value) ->
+    case is_map(Value) of
+        true ->
+            ok;
+        _ ->
+            {error, {"~p is expected to be a map.", [What]}}
+    end.
+
+all_map_keys_are_atoms(What, Map) ->
+    Filtered = [Key || Key <- maps:keys(Map), is_atom(Key)],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error, {"in ~p, keys are expected to be atoms.", [What]}}
+    end.
+
+all_rulesets_have_valid_rules(What, Rulesets) ->
+    AccOut = maps:fold(
+        fun(Ruleset, RuleTuples, AccInO) ->
+            lists:foldl(
+                fun(RuleTuple, AccInI) ->
+                    case elvis_rule:is_valid_from_tuple(RuleTuple) of
+                        {true, _Rule} ->
+                            AccInI;
+                        {false, ValidError} ->
+                            [{"in ~p, in ruleset ~p, " ++ ValidError, [What, Ruleset]} | AccInI]
+                    end
+                end,
+                AccInO,
+                RuleTuples
+            )
+        end,
+        [],
+        Rulesets
+    ),
+    case AccOut of
+        [] ->
+            ok;
+        _ ->
+            {error, lists:reverse(AccOut)}
+    end.
+
+no_rulesets_exist(What, Rulesets) ->
+    Filtered = [Ruleset || Ruleset <- maps:keys(Rulesets), not elvis_ruleset:is_defined(Ruleset)],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error,
+                {
+                    "in ~p, the following rulesets are not expected to be "
+                    "named after a default ruleset: ~p.",
+                    [
+                        What, Filtered
+                    ]
+                }}
+    end.
+
+is_valid_config(What, CustomRulesets, Configset0) ->
+    Configset = wrap_in_list(Configset0),
+    maybe
+        ok ?= is_list(What, Configset),
+        ok ?= all_configs_are_valid(What, CustomRulesets, Configset)
+    else
+        {error, FormatData} ->
+            {error, FormatData}
+    end.
+
+wrap_in_list(Term) when is_list(Term) ->
+    Term;
+wrap_in_list(Term) ->
+    [Term].
+
+all_configs_are_valid(What, CustomRulesets, Configset) ->
+    {_PosNumber, ValidErrors} = lists:foldl(
+        fun(Config, {PosNumber, AccIn}) ->
+            AccOut =
+                case config_is_valid(CustomRulesets, Config) of
+                    ok ->
+                        AccIn;
+                    {error, ValidError} ->
+                        [
+                            {"in ~p, at list position number ~p, " ++ ValidError, [What, PosNumber]}
+                            | AccIn
+                        ]
+                end,
+            {PosNumber + 1, AccOut}
+        end,
+        {1, []},
+        Configset
+    ),
+    case ValidErrors of
+        [] ->
+            ok;
+        _ ->
+            {error, lists:reverse(ValidErrors)}
+    end.
+
+get_config_opt(OptName, Config) ->
+    maps:get(OptName, Config, default_for([config, OptName])).
+
+config_is_valid(CustomRulesets, Config) ->
+    maybe
+        ok ?= map_keys_are_in(Config, [dirs, filter, ignore, ruleset, rules]),
+        Dirs = get_config_opt(dirs, Config),
+        ok ?= is_nonempty_list_of_dirs(dirs, Dirs),
+        Filter = get_config_opt(filter, Config),
+        ok ?= is_nonempty_string(filter, Filter),
+        ok ?= all_dirs_filter_combos_are_valid(Dirs, Filter),
+        Ignore = get_config_opt(ignore, Config),
+        ok ?= is_list_of_ignorables(ignore, Ignore),
+        Ruleset = get_config_opt(ruleset, Config),
+        ok ?= ruleset_is_custom_or_default(CustomRulesets, Ruleset),
+        Rules = get_config_opt(rules, Config),
+        ok ?= all_rules_are_valid(rules, Rules)
+    else
+        {error, ValidError} ->
+            {error, ValidError}
+    end.
+
+map_keys_are_in(Map, Keys) ->
+    Filtered = [Key || Key <- maps:keys(Map), not lists:member(Key, Keys)],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error, io_lib:format("the following keys are unknown: ~p.", [Filtered])}
+    end.
+
+is_nonempty_list_of_dirs(What, List) when not is_list(List) ->
+    {error, io_lib:format("~p is expected to be a list.", [What])};
+is_nonempty_list_of_dirs(What, [] = _List) ->
+    {error, io_lib:format("~p is expected to be a nonempty list.", [What])};
+is_nonempty_list_of_dirs(What, List) ->
+    Filtered = [
+        Element
+     || Element <- List, not io_lib:char_list(Element) orelse not filelib:is_dir(Element)
+    ],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error,
+                io_lib:format("in ~p, the following elements are not directories: ~p.", [
+                    What, Filtered
+                ])}
+    end.
+
+is_nonempty_string(What, String) ->
+    case io_lib:char_list(String) andalso length(String) > 0 of
+        true ->
+            ok;
+        _ ->
+            {error, io_lib:format("~p is expected to be a non-empty string.", [What])}
+    end.
+
+all_dirs_filter_combos_are_valid(Dirs, Filter) ->
+    AccOut = lists:foldl(
+        fun(Dir, AccIn) ->
+            case filelib:wildcard(filename:join(Dir, Filter)) of
+                [_ | _] ->
+                    AccIn;
+                _ ->
+                    [
+                        io_lib:format("dir + filter combo ~p + ~p yielded no files to analyse.", [
+                            Dir, Filter
+                        ])
+                        | AccIn
+                    ]
+            end
+        end,
+        [],
+        Dirs
+    ),
+    case AccOut of
+        [] ->
+            ok;
+        _ ->
+            {error, lists:reverse(AccOut)}
+    end.
+
+is_list_of_ignorables(What, List) when not is_list(List) ->
+    {error, io_lib:format("~p is expected to be a list.", [What])};
+is_list_of_ignorables(What, List) ->
+    Filtered = [Element || Element <- List, not elvis_rule:is_ignorable(Element)],
+    case Filtered of
+        [] ->
+            ok;
+        _ ->
+            {error,
+                io_lib:format("in ~p, the following elements are not ignorable: ~p.", [
+                    What, Filtered
+                ])}
+    end.
+
+ruleset_is_custom_or_default(CustomRulesets, Ruleset) ->
+    case
+        lists:member(Ruleset, maps:keys(CustomRulesets)) orelse elvis_ruleset:is_defined(Ruleset)
+    of
+        true ->
+            ok;
+        _ ->
+            {error,
+                io_lib:format("~p is expected to be either a custom or a default ruleset.", [
+                    Ruleset
+                ])}
+    end.
+
+all_rules_are_valid(What, RuleTuples) when not is_list(RuleTuples) ->
+    {error, io_lib:format("~p is expected to be a list.", [What])};
+all_rules_are_valid(What, RuleTuples) ->
+    AccOut = lists:foldl(
+        fun(RuleTuple, AccInI) ->
+            case elvis_rule:is_valid_from_tuple(RuleTuple) of
+                {true, Rule} ->
+                    check_rule_for_options(Rule, AccInI);
+                {false, ValidError} ->
+                    [io_lib:format("in ~p, " ++ ValidError, [What]) | AccInI]
+            end
+        end,
+        [],
+        RuleTuples
+    ),
+    case AccOut of
+        [] ->
+            ok;
+        _ ->
+            {error, lists:reverse(AccOut)}
+    end.
+
+check_rule_for_options(Rule, AccInI) ->
+    case elvis_rule:defkeys(Rule) of
+        [] ->
+            % No further validation possible.
+            AccInI;
+        DefKeysInput ->
+            NS = elvis_rule:ns(Rule),
+            Name = elvis_rule:name(Rule),
+            % Bypass new/ constraints.
+            DefKeys = maps:keys(NS:default(Name)) ++ [ignore],
+            case DefKeysInput -- DefKeys of
+                [] ->
+                    AccInI;
+                Extra ->
+                    [
+                        io_lib:format(
+                            "in rule ~p/~p, the following options are unknown: ~p.",
+                            [NS, Name, Extra]
+                        ),
+                        AccInI
+                    ]
+            end
+    end.
+
+flag({_Option, _What} = Obj) ->
+    Table = table(),
+    _ = create_table(Table),
+    true = ets:insert(Table, Obj),
+    ok.
+
+check_flag({Option, _What} = Obj) ->
+    Table = table(),
+    table_exists(Table) andalso ets:lookup(Table, Option) =:= [Obj].
+
+validated(Option) ->
+    {Option, validated}.
+
+validation_started(Option) ->
+    {Option, validation_started}.
+
+create_table(Table) ->
+    case table_exists(Table) of
+        false ->
+            _ = ets:new(Table, [public, named_table]);
+        _ ->
+            ok
+    end.
+
+table() ->
+    ?MODULE.
+
+table_exists(Table) ->
+    ets:info(Table) =/= undefined.
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 2843aefc..0df407a7 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -66,7 +66,7 @@ rock_this(Path, ElvisConfig) ->
         end,
     case lists:filter(FilterFun, ElvisConfig) of
         [] ->
-            elvis_utils:info("Skipping ~s", [Path]);
+            elvis_utils:output(info, "Skipping ~s", [Path]);
         FilteredElvisConfig ->
             LoadedFile = load_file_data(FilteredElvisConfig, File),
             ApplyRulesFun = fun(Cfg) -> apply_rules_and_print(Cfg, LoadedFile) end,
@@ -116,13 +116,13 @@ do_rock(File, ElvisConfig) ->
     elvis_file:t().
 load_file_data(ElvisConfig, File) ->
     Path = elvis_file:path(File),
-    elvis_utils:info("Loading ~s", [Path]),
+    elvis_utils:output(info, "Loading ~s", [Path]),
     try
         elvis_file:load_file_data(ElvisConfig, File)
     catch
         _:Reason ->
             Msg = "~p when loading file ~p.",
-            elvis_utils:error_prn(Msg, [Reason, Path]),
+            elvis_utils:output(error, Msg, [Reason, Path]),
             File
     end.
 
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index 71440e67..65817aff 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -184,9 +184,9 @@ print(Format, #{file := Path, rules := Rules}) ->
         _ ->
             case status(Rules) of
                 ok ->
-                    elvis_utils:notice("# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
+                    elvis_utils:output(warn, "# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
                 fail ->
-                    elvis_utils:error("# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
+                    elvis_utils:output(error, "# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
             end
     end,
     print_rules(Format, Path, Rules);
@@ -213,7 +213,8 @@ print_rules(
         parsable ->
             ok;
         _ ->
-            elvis_utils:error(
+            elvis_utils:output(
+                error,
                 "  - ~p "
                 "(https://github.com/inaka/elvis_core/tree/main/doc_rules/~p/~p.md)",
                 [Name, Scope, Name]
@@ -245,7 +246,7 @@ print_item(
             FMsg = io_lib:format(Msg, Info),
             io:format("~s:~p:~p:~s~n", [File, Ln, Name, FMsg]);
         _ ->
-            elvis_utils:error("    - " ++ Msg, Info)
+            elvis_utils:output(error, "    - " ++ Msg, Info)
     end,
     print_item(Format, File, Name, Items);
 print_item(Format, File, Name, [Error | Items]) ->
@@ -255,9 +256,9 @@ print_item(_Format, _File, _Name, []) ->
     ok.
 
 print_error(#{error_msg := Msg, info := Info}) ->
-    elvis_utils:error_prn(Msg, Info);
+    elvis_utils:output(error, Msg, Info);
 print_error(#{warn_msg := Msg, info := Info}) ->
-    elvis_utils:warn_prn(Msg, Info).
+    elvis_utils:output(warn, Msg, Info).
 
 -spec status([file() | rule()]) -> ok | fail.
 status([]) ->
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 64cd7abf..607e2644 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -4,9 +4,7 @@
 
 %% General
 -export([erlang_halt/1, to_str/1, split_all_lines/1, split_all_lines/2]).
-%% Output
--export([info/2, notice/2, error/2, error_prn/2, warn_prn/2]).
-%% rebar3
+%% Output / rebar3
 -export([output/3, abort/2]).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -41,16 +39,6 @@ info(Message, Args) ->
     ColoredMessage = Message ++ "{{reset}}~n",
     print_info(ColoredMessage, Args).
 
--spec notice(string(), [term()]) -> ok.
-notice(Message, Args) ->
-    ColoredMessage = "{{white-bold}}" ++ Message ++ "{{reset}}~n",
-    print_info(ColoredMessage, Args).
-
--spec error(string(), [term()]) -> ok.
-error(Message, Args) ->
-    ColoredMessage = "{{white-bold}}" ++ Message ++ "{{reset}}~n",
-    print(ColoredMessage, Args).
-
 -spec error_prn(string(), [term()]) -> ok.
 error_prn(Message, Args) ->
     ColoredMessage = "{{red}}Error: {{reset}}" ++ Message ++ "{{reset}}~n",
@@ -115,7 +103,7 @@ escape_format_str(String) ->
     binary_to_list(ResultBin).
 
 -dialyzer({nowarn_function, output/3}).
--spec output(debug | info | error, Format :: io:format(), Data :: [term()]) -> ok.
+-spec output(debug | info | warn | error, Format :: io:format(), Data :: [term()]) -> ok.
 output(debug, Format, Data) ->
     case erlang:function_exported(rebar_api, debug, 2) of
         true ->
@@ -128,14 +116,21 @@ output(info, Format, Data) ->
         true ->
             rebar_api:info("Elvis: " ++ Format, Data);
         false ->
-            ok
+            info(Format, Data)
+    end;
+output(warn, Format, Data) ->
+    case erlang:function_exported(rebar_api, warn, 2) of
+        true ->
+            rebar_api:warn("Elvis: " ++ Format, Data);
+        false ->
+            warn_prn(Format, Data)
     end;
 output(error, Format, Data) ->
     case erlang:function_exported(rebar_api, error, 2) of
         true ->
             rebar_api:error("Elvis: " ++ Format, Data);
         false ->
-            ok
+            error_prn(Format, Data)
     end.
 
 -dialyzer({nowarn_function, abort/2}).

From 60bef3ff83ea7781ad99dc50a6223006bd539c68 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Tue, 15 Jul 2025 22:12:37 +0100
Subject: [PATCH 20/67] Act on test results and prepare for final touches

---
 config/elvis-test-custom-ruleset.config      |   2 +-
 config/elvis-umbrella.config                 |   4 +-
 config/elvis.config                          |   2 +-
 config/test.config                           |   2 +-
 elvis.config                                 |   2 +-
 src/elvis_config.erl                         | 312 ++++++++++---------
 src/elvis_core.erl                           |   2 +
 src/elvis_result.erl                         |   2 +-
 src/elvis_ruleset.erl                        |  19 +-
 src/elvis_utils.erl                          |  88 ++----
 test/dirs/apps/app3/include/app3_example.hrl |   0
 test/dirs/apps/app3/rebar.config             |   1 +
 test/dirs/apps/app3/src/app3_example.erl     |   1 +
 test/elvis_SUITE.erl                         |  42 +--
 test/examples/invalid_rules.elvis.config     |   2 +-
 test/examples/user_defined_rules.erl         |   4 +-
 16 files changed, 256 insertions(+), 229 deletions(-)
 create mode 100644 test/dirs/apps/app3/include/app3_example.hrl
 create mode 100644 test/dirs/apps/app3/rebar.config
 create mode 100644 test/dirs/apps/app3/src/app3_example.erl

diff --git a/config/elvis-test-custom-ruleset.config b/config/elvis-test-custom-ruleset.config
index 0ce339a9..b14c9ba6 100644
--- a/config/elvis-test-custom-ruleset.config
+++ b/config/elvis-test-custom-ruleset.config
@@ -3,7 +3,7 @@
         {rulesets, #{project => [{elvis_text_style, no_tabs}]}},
         {config, [
             #{
-                dirs => ["."],
+                dirs => ["../../_build/test/lib/elvis_core/test/dirs/src"],
                 filter => "*.erl",
                 ruleset => project
             }
diff --git a/config/elvis-umbrella.config b/config/elvis-umbrella.config
index ad3f8dff..59050ea8 100644
--- a/config/elvis-umbrella.config
+++ b/config/elvis-umbrella.config
@@ -4,8 +4,8 @@
             #{
                 dirs =>
                     [
-                        "../../_build/test/lib/elvis_core/test/dirs/src/**",
-                        "../../_build/test/lib/elvis_core/test/dirs/test/**",
+                        "../../_build/test/lib/elvis_core/test/dirs/src",
+                        "../../_build/test/lib/elvis_core/test/dirs/test",
                         "../../_build/test/lib/elvis_core/test/dirs/apps/**/src",
                         "../../_build/test/lib/elvis_core/test/dirs/apps/**/test"
                     ],
diff --git a/config/elvis.config b/config/elvis.config
index a68f4ced..693b2c52 100644
--- a/config/elvis.config
+++ b/config/elvis.config
@@ -22,7 +22,7 @@
                 ruleset => beam_files
             },
             #{
-                dirs => ["."],
+                dirs => ["../.."],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
diff --git a/config/test.config b/config/test.config
index 1cdd1dd9..155962b8 100644
--- a/config/test.config
+++ b/config/test.config
@@ -34,7 +34,7 @@
             },
             #{
                 dirs => ["../../_build/test/lib/elvis_core/test/examples"],
-                filter => "rebar.config",
+                filter => "rebar3.config.success",
                 ruleset => rebar_config
             },
             #{
diff --git a/elvis.config b/elvis.config
index 310c50f1..c8e15c05 100644
--- a/elvis.config
+++ b/elvis.config
@@ -14,7 +14,7 @@
                         }},
                         {elvis_style, dont_repeat_yourself, #{min_complexity => 20}},
                         {elvis_style, no_debug_call, #{
-                            ignore => [{elvis_result, print_item, 4}, {elvis_utils, print, 2}]
+                            ignore => [{elvis_result, print_item, 4}, {elvis_utils, do_output, 2}]
                         }},
                         {elvis_style, no_god_modules, #{ignore => [elvis_style]}},
                         {elvis_style, no_throw, disable},
diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index c1c58c2c..07117572 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -2,8 +2,8 @@
 
 -feature(maybe_expr, enable).
 
--export([from_rebar/1, from_file/1]).
-%% Geters
+-export([from_rebar/1, from_file/1, validate_config/1, default/0]).
+%% Getters
 -export([dirs/1, ignore/1, filter/1, files/1, rules/1]).
 %% Files
 -export([resolve_files/1, resolve_files/2, apply_to_files/2]).
@@ -24,11 +24,17 @@
 %%% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-fetch_elvis_config(AppConfig) ->
-    ElvisConfig = from_static(elvis, {app, AppConfig}),
-    _ = validate({elvis, ElvisConfig}),
-    _ = elvis_ruleset:load_custom(from_static(rulesets, {elvis, ElvisConfig})),
-    ElvisConfig.
+fetch_elvis_config(Key, AppConfig) ->
+    Elvis = from_static(elvis, {app, AppConfig}),
+    _ =
+        case lists:member(Key, elvis_control_opts()) of
+            true ->
+                ok;
+            _ ->
+                do_validate({elvis, Elvis})
+        end,
+    _ = elvis_ruleset:load_custom(from_static(rulesets, {elvis, Elvis})),
+    Elvis.
 
 from_static(Key, {Type, Config}) ->
     elvis_utils:output(debug, "fetching key ~p from ~p config.", [Key, Type]),
@@ -88,8 +94,8 @@ for(Key) ->
                 AppConfig0
         end,
     % If we got this far, the config. is valid...
-    ElvisConfig = fetch_elvis_config(AppConfig),
-    from_static(Key, {elvis, ElvisConfig}).
+    Elvis = fetch_elvis_config(Key, AppConfig),
+    from_static(Key, {elvis, Elvis}).
 
 consult_elvis_config(File) ->
     case file:consult(File) of
@@ -116,12 +122,12 @@ from_rebar(File) ->
     fetch_elvis_config_from(AppConfig).
 
 from_file(File) ->
-    FileConfig = consult_elvis_config(File),
-    fetch_elvis_config_from(FileConfig).
+    AppConfig = consult_elvis_config(File),
+    fetch_elvis_config_from(AppConfig).
 
 fetch_elvis_config_from(AppConfig) ->
-    ElvisConfig = fetch_elvis_config(AppConfig),
-    from_static(config, {elvis, ElvisConfig}).
+    Elvis = fetch_elvis_config(undefined, AppConfig),
+    from_static(config, {elvis, Elvis}).
 
 default_for(app) ->
     % This is the top-level element, before 'elvis'
@@ -129,6 +135,29 @@ default_for(app) ->
 default_for(elvis) ->
     [];
 default_for(config) ->
+    [];
+default_for(output_format) ->
+    colors;
+default_for(verbose) ->
+    false;
+default_for(no_output) ->
+    false;
+default_for(parallel) ->
+    1;
+default_for(rulesets) ->
+    #{};
+default_for([config, dirs]) ->
+    [];
+default_for([config, filter]) ->
+    "";
+default_for([config, ignore]) ->
+    [];
+default_for([config, ruleset]) ->
+    undefined;
+default_for([config, rules]) ->
+    [].
+
+default() ->
     [
         #{
             dirs => [
@@ -158,27 +187,7 @@ default_for(config) ->
             filter => ".gitignore",
             ruleset => gitignore
         }
-    ];
-default_for(output_format) ->
-    colors;
-default_for(verbose) ->
-    false;
-default_for(no_output) ->
-    false;
-default_for(parallel) ->
-    1;
-default_for(rulesets) ->
-    #{};
-default_for([config, dirs]) ->
-    [];
-default_for([config, filter]) ->
-    "";
-default_for([config, ignore]) ->
-    [];
-default_for([config, ruleset]) ->
-    undefined;
-default_for([config, rules]) ->
-    [].
+    ].
 
 -spec dirs(Config :: [t()] | t()) -> [string()].
 dirs(Config) when is_list(Config) ->
@@ -253,7 +262,9 @@ resolve_files(#{files := _Files} = RuleGroup) ->
 resolve_files(#{dirs := Dirs} = RuleGroup) ->
     Filter = filter(RuleGroup),
     Files = elvis_file:find_files(Dirs, Filter),
-    resolve_files(RuleGroup, Files).
+    resolve_files(RuleGroup, Files);
+resolve_files(#{}) ->
+    [].
 
 %% @doc Takes a function and configuration and applies the function to all
 %%      file in the configuration.
@@ -290,7 +301,7 @@ merge_rules(UserRules, DefaultRules) ->
             % wants to override the rule.
             fun(Tuple) ->
                 Rule = elvis_rule:from_tuple(Tuple),
-                case not is_rule_override(Rule, UserRules) of
+                case not is_rule_override(Rule, UserRules) andalso not elvis_rule:disabled(Rule) of
                     true ->
                         {true, Rule};
                     false ->
@@ -330,63 +341,76 @@ is_rule_override(Rule, UserRules) ->
         UserRules
     ).
 
-validate({elvis = Option, ElvisConfig}) ->
-    case check_flag(validated(Option)) orelse check_flag(validation_started(Option)) of
-        true ->
-            ok;
-        false ->
-            do_validate({Option, ElvisConfig})
-    end.
+validate_config(ElvisConfig) ->
+    do_validate({config, ElvisConfig}).
 
-get_elvis_opt(OptName, ElvisConfig) ->
-    proplists:get_value(OptName, ElvisConfig, default_for(OptName)).
+get_elvis_opt(OptName, Elvis) ->
+    proplists:get_value(OptName, Elvis, default_for(OptName)).
 
-do_validate({elvis = Option, ElvisConfig}) ->
-    maybe
-        ok = flag(validation_started(Option)),
-        ok ?= is_list("elvis", ElvisConfig),
-        ok ?=
-            proplist_keys_are_in("elvis", ElvisConfig, [
-                output_format, verbose, no_output, parallel, rulesets, config
-            ]),
-        OutputFormat = get_elvis_opt(output_format, ElvisConfig),
-        ok ?= is_one_of("elvis.output_format", OutputFormat, [colors, plain, parsable]),
-        Verbose = get_elvis_opt(verbose, ElvisConfig),
-        ok ?= is_boolean("elvis.verbose", Verbose),
-        NoOutput = get_elvis_opt(no_output, ElvisConfig),
-        ok ?= is_boolean("elvis.no_output", NoOutput),
-        Parallel = get_elvis_opt(parallel, ElvisConfig),
-        ok ?= is_pos_integer("elvis.parallel", Parallel),
-        Rulesets = get_elvis_opt(rulesets, ElvisConfig),
-        ok ?= is_valid_rulesets("elvis.rulesets", Rulesets),
-        Config = get_elvis_opt(config, ElvisConfig),
-        ok ?= is_valid_config("elvis.config", Rulesets, Config),
-        ok = flag(validated(Option))
-    else
-        {error, FormatData} ->
-            {Format, Data} =
-                case is_list(FormatData) of
-                    false ->
-                        FormatData;
-                    true ->
-                        % Get only first result, for now
-                        % If we wanna be smarter we need to start concatenating readable strings
-                        [{Format0, Data0} | _] = FormatData,
-                        {Format0, Data0}
-                end,
-            % on warnings_as_errors this'll throw an exception
-            %throw({invalid_config, io_lib:format(Format, Data)})
-            elvis_utils:output(warn, Format, Data)
-    end.
+elvis_control_opts() ->
+    [output_format, verbose, no_output, parallel].
 
-is_list(What, List) ->
-    case is_list(List) of
+do_validate({elvis = Option, Elvis}) ->
+    case check_flag(validation_started(Option)) of
+        true ->
+            ok;
+        _ ->
+            maybe
+                ok = flag(validation_started(Option)),
+                ok ?= is_nonempty_list("elvis", Elvis),
+                ok ?=
+                    proplist_keys_are_in(
+                        "elvis", Elvis, elvis_control_opts() ++ [rulesets, config]
+                    ),
+                OutputFormat = get_elvis_opt(output_format, Elvis),
+                ok ?= is_one_of("elvis.output_format", OutputFormat, [colors, plain, parsable]),
+                Verbose = get_elvis_opt(verbose, Elvis),
+                ok ?= is_boolean("elvis.verbose", Verbose),
+                NoOutput = get_elvis_opt(no_output, Elvis),
+                ok ?= is_boolean("elvis.no_output", NoOutput),
+                Parallel = get_elvis_opt(parallel, Elvis),
+                ok ?= is_pos_integer("elvis.parallel", Parallel),
+                CustomRulesets = get_elvis_opt(rulesets, Elvis),
+                ok ?= is_valid_rulesets("elvis.rulesets", CustomRulesets),
+                ElvisConfig = get_elvis_opt(config, Elvis),
+                ok ?= is_valid_config("elvis.config", maps:keys(CustomRulesets), ElvisConfig)
+            else
+                {error, FormatData} ->
+                    do_validate_results(FormatData)
+            end
+    end;
+do_validate({config = Option, ElvisConfig}) ->
+    case check_flag(validation_started(Option)) of
         true ->
             ok;
         _ ->
-            {error, {"~p is expected to be a list.", [What]}}
+            maybe
+                ok ?= is_valid_config("elvis.config", elvis_ruleset:custom_names(), ElvisConfig)
+            else
+                {error, FormatData} ->
+                    do_validate_results(FormatData)
+            end
     end.
 
+-spec do_validate_results(_) -> no_return().
+do_validate_results(FormatData) ->
+    {Format, Data} =
+        case is_list(FormatData) of
+            false ->
+                FormatData;
+            true ->
+                % Get only first result, for now
+                % If we wanna be smarter we need to start concatenating readable strings
+                [{Format0, Data0} | _] = FormatData,
+                {Format0, Data0}
+        end,
+    throw({invalid_config, io_lib:format(Format, Data)}).
+
+is_nonempty_list(What, List) when not is_list(List) orelse List =:= [] ->
+    {error, {"~p is expected to be a non-empty list.", [What]}};
+is_nonempty_list(_What, _List) ->
+    ok.
+
 proplist_keys_are_in(What, List, Keys) ->
     Filtered = [Element || {Element, _} <- List, not lists:member(Element, Keys)],
     case Filtered of
@@ -404,43 +428,34 @@ is_one_of(What, Value, Possibilities) ->
             {error, {"~p is expected to be one of the following: ~p.", [What, Possibilities]}}
     end.
 
-is_boolean(What, Value) ->
-    case is_boolean(Value) of
-        true ->
-            ok;
-        _ ->
-            {error, {"~p is expected to be a boolean.", [What]}}
-    end.
+is_boolean(_What, Value) when is_boolean(Value) ->
+    ok;
+is_boolean(What, _Value) ->
+    {error, {"~p is expected to be a boolean.", [What]}}.
 
-is_pos_integer(What, Value) ->
-    case is_integer(Value) andalso Value > 0 of
-        true ->
-            ok;
-        _ ->
-            {error, {"~p is expected to be a positive integer.", [What]}}
-    end.
+is_pos_integer(_What, Value) when is_integer(Value) andalso Value > 0 ->
+    ok;
+is_pos_integer(What, _Value) ->
+    {error, {"~p is expected to be a positive integer.", [What]}}.
 
-is_valid_rulesets(What, Rulesets) ->
+is_valid_rulesets(What, CustomRulesets) ->
     maybe
-        ok ?= is_map(What, Rulesets),
-        ok ?= all_map_keys_are_atoms(What, Rulesets),
-        ok ?= all_rulesets_have_valid_rules(What, Rulesets),
-        ok ?= no_rulesets_exist(What, Rulesets)
+        ok ?= is_map(What, CustomRulesets),
+        ok ?= all_map_keys_are_atoms(What, CustomRulesets),
+        ok ?= all_custom_rulesets_have_valid_rules(What, CustomRulesets),
+        ok ?= no_default_ruleset_override(What, CustomRulesets)
     else
         {error, FormatData} ->
             {error, FormatData}
     end.
 
-is_map(What, Value) ->
-    case is_map(Value) of
-        true ->
-            ok;
-        _ ->
-            {error, {"~p is expected to be a map.", [What]}}
-    end.
+is_map(_What, Value) when is_map(Value) ->
+    ok;
+is_map(What, _Value) ->
+    {error, {"~p is expected to be a map.", [What]}}.
 
 all_map_keys_are_atoms(What, Map) ->
-    Filtered = [Key || Key <- maps:keys(Map), is_atom(Key)],
+    Filtered = [Key || Key <- maps:keys(Map), not is_atom(Key)],
     case Filtered of
         [] ->
             ok;
@@ -448,16 +463,19 @@ all_map_keys_are_atoms(What, Map) ->
             {error, {"in ~p, keys are expected to be atoms.", [What]}}
     end.
 
-all_rulesets_have_valid_rules(What, Rulesets) ->
+all_custom_rulesets_have_valid_rules(What, CustomRulesets) ->
     AccOut = maps:fold(
-        fun(Ruleset, RuleTuples, AccInO) ->
+        fun(CustomRuleset, RuleTuples, AccInO) ->
             lists:foldl(
                 fun(RuleTuple, AccInI) ->
                     case elvis_rule:is_valid_from_tuple(RuleTuple) of
                         {true, _Rule} ->
                             AccInI;
                         {false, ValidError} ->
-                            [{"in ~p, in ruleset ~p, " ++ ValidError, [What, Ruleset]} | AccInI]
+                            [
+                                {"in ~p, in ruleset ~p, " ++ ValidError, [What, CustomRuleset]}
+                                | AccInI
+                            ]
                     end
                 end,
                 AccInO,
@@ -465,7 +483,7 @@ all_rulesets_have_valid_rules(What, Rulesets) ->
             )
         end,
         [],
-        Rulesets
+        CustomRulesets
     ),
     case AccOut of
         [] ->
@@ -474,8 +492,11 @@ all_rulesets_have_valid_rules(What, Rulesets) ->
             {error, lists:reverse(AccOut)}
     end.
 
-no_rulesets_exist(What, Rulesets) ->
-    Filtered = [Ruleset || Ruleset <- maps:keys(Rulesets), not elvis_ruleset:is_defined(Ruleset)],
+no_default_ruleset_override(What, CustomRulesets) ->
+    Filtered = [
+        CustomRuleset
+     || CustomRuleset <- maps:keys(CustomRulesets), elvis_ruleset:is_defined(CustomRuleset)
+    ],
     case Filtered of
         [] ->
             ok;
@@ -490,11 +511,11 @@ no_rulesets_exist(What, Rulesets) ->
                 }}
     end.
 
-is_valid_config(What, CustomRulesets, Configset0) ->
+is_valid_config(What, CustomRulesetNames, Configset0) ->
     Configset = wrap_in_list(Configset0),
     maybe
-        ok ?= is_list(What, Configset),
-        ok ?= all_configs_are_valid(What, CustomRulesets, Configset)
+        ok ?= is_nonempty_list(What, Configset),
+        ok ?= all_configs_are_valid(What, CustomRulesetNames, Configset)
     else
         {error, FormatData} ->
             {error, FormatData}
@@ -505,11 +526,11 @@ wrap_in_list(Term) when is_list(Term) ->
 wrap_in_list(Term) ->
     [Term].
 
-all_configs_are_valid(What, CustomRulesets, Configset) ->
+all_configs_are_valid(What, CustomRulesetNames, Configset) ->
     {_PosNumber, ValidErrors} = lists:foldl(
         fun(Config, {PosNumber, AccIn}) ->
             AccOut =
-                case config_is_valid(CustomRulesets, Config) of
+                case config_is_valid(CustomRulesetNames, Config) of
                     ok ->
                         AccIn;
                     {error, ValidError} ->
@@ -533,7 +554,7 @@ all_configs_are_valid(What, CustomRulesets, Configset) ->
 get_config_opt(OptName, Config) ->
     maps:get(OptName, Config, default_for([config, OptName])).
 
-config_is_valid(CustomRulesets, Config) ->
+config_is_valid(CustomRulesetNames, Config) ->
     maybe
         ok ?= map_keys_are_in(Config, [dirs, filter, ignore, ruleset, rules]),
         Dirs = get_config_opt(dirs, Config),
@@ -544,9 +565,10 @@ config_is_valid(CustomRulesets, Config) ->
         Ignore = get_config_opt(ignore, Config),
         ok ?= is_list_of_ignorables(ignore, Ignore),
         Ruleset = get_config_opt(ruleset, Config),
-        ok ?= ruleset_is_custom_or_default(CustomRulesets, Ruleset),
+        ok ?= defined_ruleset_is_custom_or_default(CustomRulesetNames, Ruleset),
         Rules = get_config_opt(rules, Config),
-        ok ?= all_rules_are_valid(rules, Rules)
+        ok ?= all_rules_are_valid(rules, Rules),
+        ok ?= either_rules_is_nonempty_or_ruleset_is_defined(Rules, Ruleset)
     else
         {error, ValidError} ->
             {error, ValidError}
@@ -561,25 +583,29 @@ map_keys_are_in(Map, Keys) ->
             {error, io_lib:format("the following keys are unknown: ~p.", [Filtered])}
     end.
 
-is_nonempty_list_of_dirs(What, List) when not is_list(List) ->
-    {error, io_lib:format("~p is expected to be a list.", [What])};
-is_nonempty_list_of_dirs(What, [] = _List) ->
-    {error, io_lib:format("~p is expected to be a nonempty list.", [What])};
+is_nonempty_list_of_dirs(What, List) when not is_list(List) orelse List =:= [] ->
+    {error, io_lib:format("~p is expected to be a non-empty list.", [What])};
 is_nonempty_list_of_dirs(What, List) ->
     Filtered = [
         Element
-     || Element <- List, not io_lib:char_list(Element) orelse not filelib:is_dir(Element)
+     || Element <- List, not io_lib:char_list(Element) orelse not holds_dir(Element)
     ],
     case Filtered of
         [] ->
             ok;
         _ ->
             {error,
-                io_lib:format("in ~p, the following elements are not directories: ~p.", [
-                    What, Filtered
-                ])}
+                io_lib:format(
+                    "in ~p, the following elements are not (or don't contain) directories: ~p.",
+                    [What, Filtered]
+                )}
     end.
 
+holds_dir(Element) ->
+    Dirs = filelib:wildcard(Element),
+    Filtered = [Dir || Dir <- Dirs, filelib:is_dir(Dir)],
+    Filtered =/= [].
+
 is_nonempty_string(What, String) ->
     case io_lib:char_list(String) andalso length(String) > 0 of
         true ->
@@ -627,10 +653,10 @@ is_list_of_ignorables(What, List) ->
                 ])}
     end.
 
-ruleset_is_custom_or_default(CustomRulesets, Ruleset) ->
-    case
-        lists:member(Ruleset, maps:keys(CustomRulesets)) orelse elvis_ruleset:is_defined(Ruleset)
-    of
+defined_ruleset_is_custom_or_default(_CustomRulesetNames, undefined = _Ruleset) ->
+    ok;
+defined_ruleset_is_custom_or_default(CustomRulesetNames, Ruleset) ->
+    case lists:member(Ruleset, CustomRulesetNames) orelse elvis_ruleset:is_defined(Ruleset) of
         true ->
             ok;
         _ ->
@@ -662,6 +688,13 @@ all_rules_are_valid(What, RuleTuples) ->
             {error, lists:reverse(AccOut)}
     end.
 
+either_rules_is_nonempty_or_ruleset_is_defined([_ | _] = _Rules, _Ruleset) ->
+    ok;
+either_rules_is_nonempty_or_ruleset_is_defined(_Rules, Ruleset) when Ruleset =/= undefined ->
+    ok;
+either_rules_is_nonempty_or_ruleset_is_defined(_Rules, _Ruleset) ->
+    io_lib:format("either rules or ruleset is expected to be defined.", []).
+
 check_rule_for_options(Rule, AccInI) ->
     case elvis_rule:defkeys(Rule) of
         [] ->
@@ -696,9 +729,6 @@ check_flag({Option, _What} = Obj) ->
     Table = table(),
     table_exists(Table) andalso ets:lookup(Table, Option) =:= [Obj].
 
-validated(Option) ->
-    {Option, validated}.
-
 validation_started(Option) ->
     {Option, validation_started}.
 
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 0df407a7..35ad8e9f 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -35,6 +35,7 @@ start() ->
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
+    ok = elvis_config:validate_config(ElvisConfig),
     elvis_ruleset:dump_custom(),
     Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
     lists:foldl(fun combine_results/2, ok, Results).
@@ -46,6 +47,7 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
+    ok = elvis_config:validate_config(ElvisConfig),
     elvis_ruleset:dump_custom(),
     Dirname = filename:dirname(Path),
     Filename = filename:basename(Path),
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index 65817aff..eb0154db 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -184,7 +184,7 @@ print(Format, #{file := Path, rules := Rules}) ->
         _ ->
             case status(Rules) of
                 ok ->
-                    elvis_utils:output(warn, "# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
+                    elvis_utils:output(notice, "# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
                 fail ->
                     elvis_utils:output(error, "# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
             end
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 4ea57f92..96fb2c2e 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -2,7 +2,7 @@
 
 -format(#{inline_items => none}).
 
--export([rules/1, load_custom/1, dump_custom/0, is_defined/1]).
+-export([rules/1, load_custom/1, dump_custom/0, is_defined/1, custom_names/0]).
 
 -ifdef(TEST).
 -export([drop_custom/0]).
@@ -25,6 +25,15 @@ load_custom(Rulesets) ->
             ok
     end.
 
+custom_names() ->
+    Table = table(),
+    case ets:info(Table) of
+        undefined ->
+            [];
+        _ ->
+            proplists:get_keys(ets:tab2list(Table))
+    end.
+
 dump_custom() ->
     Table = table(),
     case ets:info(Table) of
@@ -58,6 +67,14 @@ rules(erl_files_test) ->
     erl_files_test_rules();
 rules(Group) ->
     Table = table(),
+    case ets:info(Table) of
+        undefined ->
+            [];
+        _ ->
+            lookup(Table, Group)
+    end.
+
+lookup(Table, Group) ->
     case ets:lookup(Table, Group) of
         [{Group, Rules}] ->
             Rules;
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 607e2644..1c4158d8 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -34,41 +34,6 @@ split_all_lines(Binary) ->
 split_all_lines(Binary, Opts) ->
     binary:split(Binary, [<<"\r\n">>, <<"\n">>], [global | Opts]).
 
--spec info(string(), [term()]) -> ok.
-info(Message, Args) ->
-    ColoredMessage = Message ++ "{{reset}}~n",
-    print_info(ColoredMessage, Args).
-
--spec error_prn(string(), [term()]) -> ok.
-error_prn(Message, Args) ->
-    ColoredMessage = "{{red}}Error: {{reset}}" ++ Message ++ "{{reset}}~n",
-    print(ColoredMessage, Args).
-
--spec warn_prn(string(), [term()]) -> ok.
-warn_prn(Message, Args) ->
-    ColoredMessage = "{{magenta}}Warning: {{reset}}" ++ Message ++ "{{reset}}~n",
-    print(ColoredMessage, Args).
-
--spec print_info(string(), [term()]) -> ok.
-print_info(Message, Args) ->
-    case elvis_config:verbose() of
-        true ->
-            print(Message, Args);
-        false ->
-            ok
-    end.
-
--spec print(string(), [term()]) -> ok.
-print(Message, Args) ->
-    case elvis_config:no_output() of
-        true ->
-            ok;
-        _ ->
-            Output = io_lib:format(Message, Args),
-            EscapedOutput = escape_format_str(Output),
-            io:format(parse_colors(EscapedOutput))
-    end.
-
 -spec parse_colors(string()) -> string().
 parse_colors(Message) ->
     Colors =
@@ -95,43 +60,54 @@ parse_colors(Message) ->
             lists:foldl(Fun, Message, maps:keys(Colors))
     end.
 
--spec escape_format_str(string()) -> string().
-escape_format_str(String) ->
+-spec escape_chars(string()) -> string().
+escape_chars(String) ->
     Binary = list_to_binary(String),
     Result = re:replace(Binary, "[^~]~", "~~", [global]),
     ResultBin = iolist_to_binary(Result),
     binary_to_list(ResultBin).
 
--dialyzer({nowarn_function, output/3}).
--spec output(debug | info | warn | error, Format :: io:format(), Data :: [term()]) -> ok.
-output(debug, Format, Data) ->
+-spec output(debug | info | notice | warn | error, Format :: io:format(), Data :: [term()]) -> ok.
+output(debug = _Type, Format, Data) ->
+    Chars = io_lib:format(Format, Data),
+    do_output(debug, Chars);
+output(Type, Format, Data) ->
+    Chars = io_lib:format(Format, Data),
+    EscapedChars = escape_chars(Chars),
+    ColorParsedChars = parse_colors(EscapedChars),
+    case elvis_config:no_output() of
+        true ->
+            ok;
+        _ ->
+            do_output(Type, ColorParsedChars)
+    end.
+
+-dialyzer({nowarn_function, do_output/2}).
+do_output(debug, Chars) ->
     case erlang:function_exported(rebar_api, debug, 2) of
         true ->
-            rebar_api:debug("Elvis: " ++ Format, Data);
+            rebar_api:debug("Elvis: " ++ Chars, []);
         false ->
             ok
     end;
-output(info, Format, Data) ->
-    case erlang:function_exported(rebar_api, info, 2) of
+do_output(info, Chars) ->
+    case elvis_config:verbose() of
         true ->
-            rebar_api:info("Elvis: " ++ Format, Data);
+            io:format(Chars ++ "{{reset}}~n");
         false ->
-            info(Format, Data)
+            ok
     end;
-output(warn, Format, Data) ->
-    case erlang:function_exported(rebar_api, warn, 2) of
+do_output(notice, Chars) ->
+    case elvis_config:verbose() of
         true ->
-            rebar_api:warn("Elvis: " ++ Format, Data);
+            io:format("{{white-bold}}" ++ Chars ++ "{{reset}}~n");
         false ->
-            warn_prn(Format, Data)
+            ok
     end;
-output(error, Format, Data) ->
-    case erlang:function_exported(rebar_api, error, 2) of
-        true ->
-            rebar_api:error("Elvis: " ++ Format, Data);
-        false ->
-            error_prn(Format, Data)
-    end.
+do_output(warn, Chars) ->
+    io:format("{{magenta}}Warning: {{reset}}" ++ Chars ++ "{{reset}}~n");
+do_output(error, Chars) ->
+    io:format("{{red}}Error: {{reset}}" ++ Chars ++ "{{reset}}~n").
 
 -dialyzer({nowarn_function, abort/2}).
 -spec abort(Format :: io:format(), Data :: [term()]) -> no_return().
diff --git a/test/dirs/apps/app3/include/app3_example.hrl b/test/dirs/apps/app3/include/app3_example.hrl
new file mode 100644
index 00000000..e69de29b
diff --git a/test/dirs/apps/app3/rebar.config b/test/dirs/apps/app3/rebar.config
new file mode 100644
index 00000000..0ec61832
--- /dev/null
+++ b/test/dirs/apps/app3/rebar.config
@@ -0,0 +1 @@
+{}.
diff --git a/test/dirs/apps/app3/src/app3_example.erl b/test/dirs/apps/app3/src/app3_example.erl
new file mode 100644
index 00000000..536991ea
--- /dev/null
+++ b/test/dirs/apps/app3/src/app3_example.erl
@@ -0,0 +1 @@
+-module(app3_example).
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 6a410097..27a6bd35 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -100,7 +100,13 @@ rock_with_incomplete_config(_Config) ->
         end.
 
 rock_with_list_config(_Config) ->
-    ElvisConfig = [#{dirs => ["src"], rules => [], filter => "*.erl"}],
+    ElvisConfig = [
+        #{
+            dirs => ["../../test/dirs/src"],
+            rules => [{elvis_text_style, line_length, disable}],
+            filter => "*.erl"
+        }
+    ],
     ok =
         try
             ok = elvis_core:rock(ElvisConfig)
@@ -236,22 +242,17 @@ rock_with_rule_groups(_Config) ->
     RulesGroupConfig =
         [
             #{
-                dirs => ["src"],
+                dirs => ["../../test/dirs/apps/app3/src"],
                 filter => "*.erl",
                 ruleset => erl_files
             },
             #{
-                dirs => ["include"],
-                filter => "*.erl",
+                dirs => ["../../test/dirs/apps/app3/include"],
+                filter => "*.hrl",
                 ruleset => hrl_files
             },
             #{
-                dirs => ["_build/test/lib/elvis_core/ebin"],
-                filter => "*.beam",
-                ruleset => beam_files
-            },
-            #{
-                dirs => ["."],
+                dirs => ["../../test/dirs/apps/app3"],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
@@ -287,7 +288,7 @@ rock_with_rule_groups(_Config) ->
     OverrideConfig =
         [
             #{
-                dirs => ["src"],
+                dirs => ["../../test/dirs/apps/app3/src"],
                 filter => "*.erl",
                 ruleset => erl_files,
                 rules =>
@@ -299,7 +300,7 @@ rock_with_rule_groups(_Config) ->
                     ]
             },
             #{
-                dirs => ["."],
+                dirs => ["../../test/dirs/apps/app3"],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
@@ -318,6 +319,8 @@ rock_this_skipping_files(_Config) ->
     [File] = elvis_file:find_files(Dirs, "small.erl"),
     Path = elvis_file:path(File),
     ConfigPath = "../../config/elvis-test-pa.config",
+    {ok, user_defined_rules} = compile:file("../../test/examples/user_defined_rules.erl"),
+    {module, user_defined_rules} = code:ensure_loaded(user_defined_rules),
     ElvisConfig = elvis_config:from_file(ConfigPath),
     ok = elvis_core:rock_this(Path, ElvisConfig),
     0 = meck:num_calls(elvis_file, load_file_data, '_'),
@@ -341,6 +344,7 @@ rock_with_umbrella_apps(_Config) ->
     {fail, [
         #{file := "../../_build/test/lib/elvis_core/test/dirs/test/dir_test.erl"},
         #{file := "../../_build/test/lib/elvis_core/test/dirs/src/dirs_src.erl"},
+        #{file := "../../_build/test/lib/elvis_core/test/dirs/apps/app3/src/app3_example.erl"},
         #{
             file :=
                 "../../_build/test/lib/elvis_core/test/dirs/apps/app2/test/dirs_apps_app2_test.erl"
@@ -363,19 +367,12 @@ rock_with_umbrella_apps(_Config) ->
 
 rock_with_invalid_rules(_Config) ->
     ConfigPath = "../../test/examples/invalid_rules.elvis.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
-    ExpectedErrorMessage =
-        {invalid_rules, [
-            {invalid_rule, {elvis_style, not_existing_rule}},
-            {invalid_rule, {elvis_style, what_is_this_rule}},
-            {invalid_rule, {not_existing_module, dont_repeat_yourself}},
-            {invalid_rule, {not_existing_module, dont_repeat_yourself}}
-        ]},
     try
+        ElvisConfig = elvis_config:from_file(ConfigPath),
         ok = elvis_core:rock(ElvisConfig),
         ct:fail("Elvis should not have rocked with ~p", [ElvisConfig])
     catch
-        {invalid_config, ExpectedErrorMessage} ->
+        {invalid_config, _} ->
             ok
     end.
 
@@ -388,6 +385,9 @@ custom_ruleset(_Config) ->
     NoTabs = elvis_rule:new(elvis_text_style, no_tabs),
     [[NoTabs]] = elvis_config:rules(ElvisConfig),
 
+    %% this is also done by :rock and :rock_this
+    _ = elvis_ruleset:dump_custom(),
+
     %% read unknown ruleset configuration to ensure rulesets from
     %% previous load do not stick around
     ConfigPathMissing = "../../config/elvis-test-unknown-ruleset.config",
diff --git a/test/examples/invalid_rules.elvis.config b/test/examples/invalid_rules.elvis.config
index 958f1fa6..c16787ae 100644
--- a/test/examples/invalid_rules.elvis.config
+++ b/test/examples/invalid_rules.elvis.config
@@ -2,7 +2,7 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["src"],
+                dirs => ["../../_build/default/lib/elvis_core/src"],
                 filter => "*.erl",
                 rules =>
                     [
diff --git a/test/examples/user_defined_rules.erl b/test/examples/user_defined_rules.erl
index 33240cbf..656cd171 100644
--- a/test/examples/user_defined_rules.erl
+++ b/test/examples/user_defined_rules.erl
@@ -1,6 +1,6 @@
 -module(user_defined_rules).
 
--export([rule/3]).
+-export([rule/2]).
 
-rule(_Config, _Target, _) ->
+rule(_Config, _Target) ->
     [elvis_result:new_item("this will always FAIL", [], #{line => 10, column => 2})].

From b3dfaa3093eb9625777fd27fd1658f71f0a81da4 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Tue, 15 Jul 2025 22:45:36 +0100
Subject: [PATCH 21/67] Act on Xref results

---
 src/elvis_utils.erl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 1c4158d8..b8acfcec 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -7,6 +7,10 @@
 %% Output / rebar3
 -export([output/3, abort/2]).
 
+% These call (but verify if exported) rebar3-specific functions.
+-ignore_xref(do_output/2).
+-ignore_xref(abort/2).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

From a686d634f6e857b3d3be880c4d3d6b5706d08afb Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:29:08 +0100
Subject: [PATCH 22/67] Fix for erl_files_test trim'ing

---
 src/elvis_ruleset.erl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 96fb2c2e..ec92e99c 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -191,11 +191,11 @@ elvis_style_rules() ->
 
 erl_files_test_rules() ->
     trim(
+        elvis_style_rules(),
         [
             elvis_rule:new(elvis_style, dont_repeat_yourself),
             elvis_rule:new(elvis_style, no_god_modules)
-        ],
-        elvis_style_rules()
+        ]
     ).
 
 elvis_text_style_rules() ->

From 9803ffc6544127d0db285bff592b43a067c80bc0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:31:46 +0100
Subject: [PATCH 23/67] Don't be afraid to write text as it's supposed to be
 read

---
 src/elvis_config.erl | 12 ++++++------
 test/elvis_SUITE.erl |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 07117572..f18b8238 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -37,17 +37,17 @@ fetch_elvis_config(Key, AppConfig) ->
     Elvis.
 
 from_static(Key, {Type, Config}) ->
-    elvis_utils:output(debug, "fetching key ~p from ~p config.", [Key, Type]),
+    elvis_utils:output(debug, "fetching key ~p from ~p configuration", [Key, Type]),
     case proplists:get_value(Key, Config) of
         undefined ->
             elvis_utils:output(
-                debug, "no value for config. key ~p found in ~p config.; going with default", [
+                debug, "no value for key ~p found in ~p configuration; going with default", [
                     Key, Type
                 ]
             ),
             default(Key);
         Value ->
-            elvis_utils:output(debug, "value for config. key ~p found in ~p config.", [Key, Type]),
+            elvis_utils:output(debug, "value for key ~p found in ~p configuration", [Key, Type]),
             Value
     end.
 
@@ -71,12 +71,12 @@ default(Key) ->
         undefined ->
             elvis_utils:output(
                 debug,
-                "no value for config. key ~p found in application env.; going with default",
+                "no value for key ~p found in application environment; going with default",
                 [Key]
             ),
             default_for(Key);
         {ok, Value} ->
-            elvis_utils:output(debug, "value for config. key ~p found in application env.", [Key]),
+            elvis_utils:output(debug, "value for key ~p found in application environment", [Key]),
             Value
     end.
 
@@ -93,7 +93,7 @@ for(Key) ->
             AppConfig0 ->
                 AppConfig0
         end,
-    % If we got this far, the config. is valid...
+    % If we got this far, the configuration is valid...
     Elvis = fetch_elvis_config(Key, AppConfig),
     from_static(Key, {elvis, Elvis}).
 
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 27a6bd35..eb0cdae6 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -238,7 +238,7 @@ rock_without_errors_and_with_verbose_has_output(_Config) ->
 
 rock_with_rule_groups(_Config) ->
     % elvis_config will load default elvis_core rules for every
-    % rule_group in the config.
+    % rule_group in the configuration
     RulesGroupConfig =
         [
             #{

From 42fc5ce94edea4607980d652cdcaed6eb41ce087 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:32:54 +0100
Subject: [PATCH 24/67] Just because something sounds similar...

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index f18b8238..dbeee3a1 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -85,7 +85,7 @@ for(Key) ->
     AppConfig =
         case consult_elvis_config("elvis.config") of
             AppDefault ->
-                % This might happen whether we fail to parse the fail or it actually is []
+                % This might happen whether we fail to parse the file or it actually is []
                 elvis_utils:output(
                     debug, "elvis.config unusable; falling back to rebar.config", []
                 ),

From 651c6046d0f9afe9f3fd231a651d286cfa3e2e99 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:34:30 +0100
Subject: [PATCH 25/67] Care more about how it's read that correct form

---
 src/elvis_config.erl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index dbeee3a1..39eaf876 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -371,7 +371,7 @@ do_validate({elvis = Option, Elvis}) ->
                 Parallel = get_elvis_opt(parallel, Elvis),
                 ok ?= is_pos_integer("elvis.parallel", Parallel),
                 CustomRulesets = get_elvis_opt(rulesets, Elvis),
-                ok ?= is_valid_rulesets("elvis.rulesets", CustomRulesets),
+                ok ?= are_valid_rulesets("elvis.rulesets", CustomRulesets),
                 ElvisConfig = get_elvis_opt(config, Elvis),
                 ok ?= is_valid_config("elvis.config", maps:keys(CustomRulesets), ElvisConfig)
             else
@@ -438,7 +438,7 @@ is_pos_integer(_What, Value) when is_integer(Value) andalso Value > 0 ->
 is_pos_integer(What, _Value) ->
     {error, {"~p is expected to be a positive integer.", [What]}}.
 
-is_valid_rulesets(What, CustomRulesets) ->
+are_valid_rulesets(What, CustomRulesets) ->
     maybe
         ok ?= is_map(What, CustomRulesets),
         ok ?= all_map_keys_are_atoms(What, CustomRulesets),

From d7da54fe829f738dfc3254d67b9cf62236614431 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:36:39 +0100
Subject: [PATCH 26/67] Be more correct

---
 README.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 1d53ea5b..9d05de76 100644
--- a/README.md
+++ b/README.md
@@ -58,7 +58,9 @@ current directory.
 
 If `elvis.config` is not present, the application will fall back to searching for configuration
 parameters in `rebar.config`. If `rebar.config` is also unavailable, the application proceeds to
-perform a tertiary lookup within the `app/sys.config` file for the required settings.
+perform a tertiary lookup within its application environment (which can also be set via the
+`app/sys.config` file, or e.g., via `application:set_env(elvis_core, Key, Value).` for the required
+settings.
 
 #### Providing configuration as a value
 

From 48be7f6756c085ff51fac92e236bae968279c0c0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:43:12 +0100
Subject: [PATCH 27/67] Use ?MODULE less

---
 src/elvis_config.erl  | 17 ++++++-----------
 src/elvis_ruleset.erl | 36 ++++++++++++++++--------------------
 2 files changed, 22 insertions(+), 31 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 39eaf876..d85e8606 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -720,28 +720,23 @@ check_rule_for_options(Rule, AccInI) ->
     end.
 
 flag({_Option, _What} = Obj) ->
-    Table = table(),
-    _ = create_table(Table),
-    true = ets:insert(Table, Obj),
+    _ = create_table(elvis_config),
+    true = ets:insert(elvis_config, Obj),
     ok.
 
 check_flag({Option, _What} = Obj) ->
-    Table = table(),
-    table_exists(Table) andalso ets:lookup(Table, Option) =:= [Obj].
+    table_exists() andalso ets:lookup(elvis_config, Option) =:= [Obj].
 
 validation_started(Option) ->
     {Option, validation_started}.
 
 create_table(Table) ->
-    case table_exists(Table) of
+    case table_exists() of
         false ->
             _ = ets:new(Table, [public, named_table]);
         _ ->
             ok
     end.
 
-table() ->
-    ?MODULE.
-
-table_exists(Table) ->
-    ets:info(Table) =/= undefined.
+table_exists() ->
+    ets:info(elvis_config) =/= undefined.
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index ec92e99c..9abe67bd 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -26,21 +26,19 @@ load_custom(Rulesets) ->
     end.
 
 custom_names() ->
-    Table = table(),
-    case ets:info(Table) of
-        undefined ->
+    case table_exists() of
+        false ->
             [];
         _ ->
-            proplists:get_keys(ets:tab2list(Table))
+            proplists:get_keys(ets:tab2list(elvis_ruleset))
     end.
 
 dump_custom() ->
-    Table = table(),
-    case ets:info(Table) of
-        undefined ->
+    case table_exists() of
+        false ->
             ok;
         _ ->
-            ets:delete(Table)
+            ets:delete(elvis_ruleset)
     end.
 
 is_defined(Ruleset) ->
@@ -66,12 +64,11 @@ rules(rebar_config) ->
 rules(erl_files_test) ->
     erl_files_test_rules();
 rules(Group) ->
-    Table = table(),
-    case ets:info(Table) of
-        undefined ->
+    case table_exists() of
+        false ->
             [];
         _ ->
-            lookup(Table, Group)
+            lookup(elvis_ruleset, Group)
     end.
 
 lookup(Table, Group) ->
@@ -83,23 +80,22 @@ lookup(Table, Group) ->
     end.
 
 ensure_table() ->
-    Table = table(),
-    case ets:info(Table) of
-        undefined ->
-            {false, ets:new(Table, [set, named_table, {keypos, 1}, public])};
+    case table_exists() of
+        false ->
+            {false, ets:new(elvis_ruleset, [set, named_table, {keypos, 1}, public])};
         _ ->
-            {true, Table}
+            {true, elvis_ruleset}
     end.
 
-table() ->
-    ?MODULE.
-
 -ifdef(TEST).
 drop_custom() ->
     Table = table(),
     ets:delete(Table).
 -endif.
 
+table_exists() ->
+    ets:info(elvis_ruleset) =/= undefined.
+
 gitignore_rules() ->
     [
         elvis_rule:new(elvis_gitignore, forbidden_patterns),

From ee5b09387dff951ff5d381c8303d7445ad8a11d7 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 18:43:24 +0100
Subject: [PATCH 28/67] Drop unused test code

---
 src/elvis_ruleset.erl | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 9abe67bd..f80f280d 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -4,10 +4,6 @@
 
 -export([rules/1, load_custom/1, dump_custom/0, is_defined/1, custom_names/0]).
 
--ifdef(TEST).
--export([drop_custom/0]).
--endif.
-
 -spec load_custom(#{atom() => list()}) -> ok.
 load_custom(Rulesets) ->
     {Existed, Tid} = ensure_table(),
@@ -87,12 +83,6 @@ ensure_table() ->
             {true, elvis_ruleset}
     end.
 
--ifdef(TEST).
-drop_custom() ->
-    Table = table(),
-    ets:delete(Table).
--endif.
-
 table_exists() ->
     ets:info(elvis_ruleset) =/= undefined.
 

From 0734f2d3761de013278afbb83c517e6c3a73b8cb Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 19:11:39 +0100
Subject: [PATCH 29/67] Allow xref'ing further

---
 rebar.config             | 17 +++++++++++++++--
 src/elvis_code.erl       |  3 +++
 src/elvis_config.erl     |  3 +++
 src/elvis_core.erl       | 13 ++++++++++---
 src/elvis_gitignore.erl  |  3 +++
 src/elvis_project.erl    |  3 +++
 src/elvis_result.erl     |  3 +++
 src/elvis_rule.erl       |  3 +--
 src/elvis_style.erl      |  3 +++
 src/elvis_text_style.erl |  3 +++
 src/elvis_utils.erl      |  4 +++-
 11 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/rebar.config b/rebar.config
index 91aea5b4..c7757730 100644
--- a/rebar.config
+++ b/rebar.config
@@ -22,7 +22,18 @@
     ]}
 ]}.
 
-{alias, [{test, [compile, fmt, hank, xref, dialyzer, ct, cover, ex_doc]}]}.
+{alias, [
+    {test, [
+        compile,
+        fmt,
+        hank,
+        {xref, "default as test xref"},
+        {do, "default as test dialyzer"},
+        ct,
+        cover,
+        ex_doc
+    ]}
+]}.
 
 {shell, [{config, "config/test.config"}]}.
 
@@ -63,6 +74,8 @@
 
 {dialyzer, [{warnings, [no_return, unmatched_returns, error_handling, unknown]}]}.
 
-{xref_checks, [undefined_function_calls, deprecated_function_calls, deprecated_functions]}.
+{xref_checks, [
+    undefined_function_calls, deprecated_function_calls, deprecated_functions, exports_not_used
+]}.
 
 {xref_extra_paths, ["test/**"]}.
diff --git a/src/elvis_code.erl b/src/elvis_code.erl
index 8eba2a45..edfd4f7f 100644
--- a/src/elvis_code.erl
+++ b/src/elvis_code.erl
@@ -12,6 +12,9 @@
     print_node/2
 ]).
 
+% These are local debug functions.
+-ignore_xref([print_node/1, print_node/2]).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public API
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index d85e8606..95fa822f 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -20,6 +20,9 @@
 -type elvis() :: proplists:proplist().
 -export_type([elvis/0]).
 
+% API exports, not consumed locally.
+-ignore_xref([from_rebar/1, from_file/1, default/0, resolve_files/2, apply_to_files/2]).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 35ad8e9f..9eda80d1 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -4,8 +4,6 @@
 
 -export([rock/1, rock_this/2]).
 -export([start/0]).
-%% for internal use only
--export([do_rock/2]).
 %% for eating our own dogfood
 -export([main/1]).
 
@@ -13,10 +11,19 @@
 
 -ifdef(TEST).
 
--export([apply_rule/2]).
+-export([do_rock/2, apply_rule/2]).
+% For tests (we can't Xref the tests because rebar3 fails to compile some files).
+-ignore_xref([do_rock/2, apply_rule/2]).
 
 -endif.
 
+% For eating our own dogfood.
+-ignore_xref([main/1]).
+% For shell usage.
+-ignore_xref([start/0]).
+% API exports, not consumed locally.
+-ignore_xref([rock/1, rock_this/2]).
+
 -type source_filename() :: nonempty_string().
 -type target() :: source_filename() | module().
 
diff --git a/src/elvis_gitignore.erl b/src/elvis_gitignore.erl
index c2a9f16f..86414933 100644
--- a/src/elvis_gitignore.erl
+++ b/src/elvis_gitignore.erl
@@ -5,6 +5,9 @@
 
 -export([required_patterns/2, forbidden_patterns/2]).
 
+% The whole file is considered to have either callback functions or rules.
+-ignore_xref(elvis_gitignore).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Default values
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_project.erl b/src/elvis_project.erl
index 86084079..eac8554a 100644
--- a/src/elvis_project.erl
+++ b/src/elvis_project.erl
@@ -5,6 +5,9 @@
 
 -export([no_branch_deps/2, protocol_for_deps/2]).
 
+% The whole file is considered to have either callback functions or rules.
+-ignore_xref(elvis_project).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Default values
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index eb0154db..c9901aa4 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -16,6 +16,9 @@
 %% Types
 -export_type([item/0, rule/0, file/0, elvis_error/0, elvis_warn/0, attrs/0]).
 
+% API exports, not consumed locally.
+-ignore_xref([get_path/1, get_rules/1, get_items/1, get_message/1, get_info/1, get_line_num/1]).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Records
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_rule.erl b/src/elvis_rule.erl
index 1445b632..fb7a7ce8 100644
--- a/src/elvis_rule.erl
+++ b/src/elvis_rule.erl
@@ -8,7 +8,6 @@
     ns/1,
     name/1,
     def/1,
-    ignores/1,
     disabled/1,
     file/1, file/2,
     ignored/2,
@@ -182,7 +181,7 @@ disable(Rule) ->
 
 -spec ignored(Needle :: ignorable(), t()) -> boolean().
 ignored(Needle, Rule) ->
-    lists:member(Needle, Rule#rule.ignores).
+    lists:member(Needle, ignores(Rule)).
 
 -spec execute(t(), ElvisConfig) -> Results when
     ElvisConfig :: elvis_config:t(),
diff --git a/src/elvis_style.erl b/src/elvis_style.erl
index b5f1ed2a..b56d32b2 100644
--- a/src/elvis_style.erl
+++ b/src/elvis_style.erl
@@ -63,6 +63,9 @@
     prefer_include/2
 ]).
 
+% The whole file is considered to have either callback functions or rules.
+-ignore_xref(elvis_style).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Default values
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_text_style.erl b/src/elvis_text_style.erl
index c1ba7e05..2cf97618 100644
--- a/src/elvis_text_style.erl
+++ b/src/elvis_text_style.erl
@@ -10,6 +10,9 @@
     no_redundant_blank_lines/2
 ]).
 
+% The whole file is considered to have either callback functions or rules.
+-ignore_xref(elvis_text_style).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Default values
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index b8acfcec..4b234e2c 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -11,11 +11,13 @@
 -ignore_xref(do_output/2).
 -ignore_xref(abort/2).
 
+% API exports, not consumed locally.
+-ignore_xref([erlang_halt/1]).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-%% @doc This is defined so that it can be mocked for tests.
 -spec erlang_halt(integer()) -> no_return().
 erlang_halt(Code) ->
     halt(Code).

From 540b064ca13f84ab426fdc992f38f91a00eae38f Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 19:13:07 +0100
Subject: [PATCH 30/67] Make it compilation error -free

---
 src/elvis_core.erl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 9eda80d1..425d245e 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -114,6 +114,8 @@ do_parallel_rock(ElvisConfig0) ->
             {fail, [{T, E}]}
     end.
 
+-ifdef(TEST).
+
 -spec do_rock(elvis_file:t(), [elvis_config:t()] | elvis_config:t()) ->
     {ok, elvis_result:file()}.
 do_rock(File, ElvisConfig) ->
@@ -121,6 +123,8 @@ do_rock(File, ElvisConfig) ->
     Results = apply_rules(ElvisConfig, LoadedFile),
     {ok, Results}.
 
+-endif.
+
 -spec load_file_data([elvis_config:t()] | elvis_config:t(), elvis_file:t()) ->
     elvis_file:t().
 load_file_data(ElvisConfig, File) ->

From 836f4946bd788f5a5ce2f3eb7033bd35a463aa86 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 19:32:40 +0100
Subject: [PATCH 31/67] Ease it again!

---
 rebar.config | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/rebar.config b/rebar.config
index c7757730..4b0cf02c 100644
--- a/rebar.config
+++ b/rebar.config
@@ -23,16 +23,7 @@
 ]}.
 
 {alias, [
-    {test, [
-        compile,
-        fmt,
-        hank,
-        {xref, "default as test xref"},
-        {do, "default as test dialyzer"},
-        ct,
-        cover,
-        ex_doc
-    ]}
+    {test, [compile, fmt, hank, xref, dialyzer, ct, cover, ex_doc]}
 ]}.
 
 {shell, [{config, "config/test.config"}]}.

From 5d4664fbf0936aa26ae970e2ece3dd97eb2a5227 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 19:47:20 +0100
Subject: [PATCH 32/67] Go with no-throw-but-error, by default

Later, when we implement warnings_as_errors we can tweak this
to return ok even if there are warnings (while they're still
printed by elvis_core)

It simplifies the consumption API and the tests (no more
unnecessary catches)
---
 src/elvis_config.erl |  9 ++++-
 src/elvis_core.erl   | 79 ++++++++++++++++++++++---------------
 test/elvis_SUITE.erl | 94 +++++++-------------------------------------
 3 files changed, 70 insertions(+), 112 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 95fa822f..080e082a 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -129,8 +129,13 @@ from_file(File) ->
     fetch_elvis_config_from(AppConfig).
 
 fetch_elvis_config_from(AppConfig) ->
-    Elvis = fetch_elvis_config(undefined, AppConfig),
-    from_static(config, {elvis, Elvis}).
+    try fetch_elvis_config(undefined, AppConfig) of
+        Elvis ->
+            from_static(config, {elvis, Elvis})
+    catch
+        {invalid_config, _} = Caught ->
+            {fail, [{throw, Caught}]}
+    end.
 
 default_for(app) ->
     % This is the top-level element, before 'elvis'
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 425d245e..0e055c43 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -37,15 +37,28 @@ start() ->
     {ok, _} = application:ensure_all_started(elvis_core),
     ok.
 
+validate_config_or_throw(ElvisConfig) ->
+    try elvis_config:validate_config(ElvisConfig) of
+        ok ->
+            ok
+    catch
+        {invalid_config, _} = Caught ->
+            {error, {fail, [{throw, Caught}]}}
+    end.
+
 %% In this context, `throw` means an error, e.g., validation or internal, not an actual
 %% call to `erlang:throw/1`.
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
-    ok = elvis_config:validate_config(ElvisConfig),
-    elvis_ruleset:dump_custom(),
-    Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
-    lists:foldl(fun combine_results/2, ok, Results).
+    case validate_config_or_throw(ElvisConfig) of
+        ok ->
+            elvis_ruleset:dump_custom(),
+            Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
+            lists:foldl(fun combine_results/2, ok, Results);
+        {error, Error} ->
+            Error
+    end.
 
 -spec rock_this(target(), [elvis_config:t()]) ->
     ok | {fail, [elvis_result:file() | elvis_result:rule()]}.
@@ -54,33 +67,37 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
-    ok = elvis_config:validate_config(ElvisConfig),
-    elvis_ruleset:dump_custom(),
-    Dirname = filename:dirname(Path),
-    Filename = filename:basename(Path),
-    File =
-        case elvis_file:find_files([Dirname], Filename) of
-            [] ->
-                throw({enoent, Path});
-            [File0] ->
-                File0
-        end,
-
-    FilterFun =
-        fun(Cfg) ->
-            Filter = elvis_config:filter(Cfg),
-            Dirs = elvis_config:dirs(Cfg),
-            IgnoreList = elvis_config:ignore(Cfg),
-            [] =/= elvis_file:filter_files([File], Dirs, Filter, IgnoreList)
-        end,
-    case lists:filter(FilterFun, ElvisConfig) of
-        [] ->
-            elvis_utils:output(info, "Skipping ~s", [Path]);
-        FilteredElvisConfig ->
-            LoadedFile = load_file_data(FilteredElvisConfig, File),
-            ApplyRulesFun = fun(Cfg) -> apply_rules_and_print(Cfg, LoadedFile) end,
-            Results = lists:map(ApplyRulesFun, FilteredElvisConfig),
-            elvis_result_status(Results)
+    case validate_config_or_throw(ElvisConfig) of
+        ok ->
+            elvis_ruleset:dump_custom(),
+            Dirname = filename:dirname(Path),
+            Filename = filename:basename(Path),
+            File =
+                case elvis_file:find_files([Dirname], Filename) of
+                    [] ->
+                        throw({enoent, Path});
+                    [File0] ->
+                        File0
+                end,
+
+            FilterFun =
+                fun(Cfg) ->
+                    Filter = elvis_config:filter(Cfg),
+                    Dirs = elvis_config:dirs(Cfg),
+                    IgnoreList = elvis_config:ignore(Cfg),
+                    [] =/= elvis_file:filter_files([File], Dirs, Filter, IgnoreList)
+                end,
+            case lists:filter(FilterFun, ElvisConfig) of
+                [] ->
+                    elvis_utils:output(info, "Skipping ~s", [Path]);
+                FilteredElvisConfig ->
+                    LoadedFile = load_file_data(FilteredElvisConfig, File),
+                    ApplyRulesFun = fun(Cfg) -> apply_rules_and_print(Cfg, LoadedFile) end,
+                    Results = lists:map(ApplyRulesFun, FilteredElvisConfig),
+                    elvis_result_status(Results)
+            end;
+        {error, Error} ->
+            Error
     end.
 
 %% In this context, `throw` means an error, e.g., validation or internal, not an actual
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index eb0cdae6..85f77f97 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -61,43 +61,18 @@ end_per_suite(Config) ->
 %%% Rocking
 
 rock_with_empty_map_config(_Config) ->
-    ok =
-        try
-            ok = elvis_core:rock([#{}]),
-            fail
-        catch
-            {invalid_config, _} ->
-                ok
-        end,
-    ok =
-        try
-            ok = elvis_core:rock([#{} || X <- lists:seq(1, 10), X < 1]),
-            fail
-        catch
-            {invalid_config, _} ->
-                ok
-        end.
+    {fail, [{throw, {invalid_config, _}}]} = elvis_core:rock([#{}]),
+    {fail, [{throw, {invalid_config, _}}]} = elvis_core:rock([]),
+    ok.
 
 rock_with_empty_list_config(_Config) ->
-    ok =
-        try
-            ok = elvis_core:rock([#{}, #{}]),
-            fail
-        catch
-            {invalid_config, _} ->
-                ok
-        end.
+    {fail, [{throw, {invalid_config, _}}]} = elvis_core:rock([#{}, #{}]),
+    ok.
 
 rock_with_incomplete_config(_Config) ->
     ElvisConfig = [#{dirs => ["src"]}],
-    ok =
-        try
-            ok = elvis_core:rock(ElvisConfig),
-            fail
-        catch
-            {invalid_config, _} ->
-                ok
-        end.
+    {fail, [{throw, {invalid_config, _}}]} = elvis_core:rock(ElvisConfig),
+    ok.
 
 rock_with_list_config(_Config) ->
     ElvisConfig = [
@@ -107,13 +82,7 @@ rock_with_list_config(_Config) ->
             filter => "*.erl"
         }
     ],
-    ok =
-        try
-            ok = elvis_core:rock(ElvisConfig)
-        catch
-            {invalid_config, _} ->
-                fail
-        end.
+    ok = elvis_core:rock(ElvisConfig).
 
 rock_with_file_config(_Config) ->
     ConfigPath = "../../config/elvis.config",
@@ -257,13 +226,7 @@ rock_with_rule_groups(_Config) ->
                 ruleset => rebar_config
             }
         ],
-    ok =
-        try
-            ok = elvis_core:rock(RulesGroupConfig)
-        catch
-            {invalid_config, _} ->
-                fail
-        end,
+    ok = elvis_core:rock(RulesGroupConfig),
     % Override default elvis_core rules without ruleset should fail.
     OverrideFailConfig =
         [
@@ -276,14 +239,7 @@ rock_with_rule_groups(_Config) ->
                     ]
             }
         ],
-    ok =
-        try
-            _ = elvis_core:rock(OverrideFailConfig),
-            fail
-        catch
-            {invalid_config, _} ->
-                ok
-        end,
+    {fail, [{throw, {invalid_config, _}}]} = elvis_core:rock(OverrideFailConfig),
     % Override default elvis_core rules.
     OverrideConfig =
         [
@@ -305,13 +261,7 @@ rock_with_rule_groups(_Config) ->
                 ruleset => rebar_config
             }
         ],
-    ok =
-        try
-            ok = elvis_core:rock(OverrideConfig)
-        catch
-            {invalid_config, _} ->
-                fail
-        end.
+    ok = elvis_core:rock(OverrideConfig).
 
 rock_this_skipping_files(_Config) ->
     meck:new(elvis_file, [passthrough]),
@@ -367,14 +317,8 @@ rock_with_umbrella_apps(_Config) ->
 
 rock_with_invalid_rules(_Config) ->
     ConfigPath = "../../test/examples/invalid_rules.elvis.config",
-    try
-        ElvisConfig = elvis_config:from_file(ConfigPath),
-        ok = elvis_core:rock(ElvisConfig),
-        ct:fail("Elvis should not have rocked with ~p", [ElvisConfig])
-    catch
-        {invalid_config, _} ->
-            ok
-    end.
+    {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(ConfigPath),
+    ok.
 
 %%%%%%%%%%%%%%%
 %%% Utils
@@ -411,16 +355,8 @@ hrl_ruleset(_Config) ->
 throw_configuration(_Config) ->
     Filename = "./elvis.config",
     ok = file:write_file(Filename, <<"-">>),
-    ok =
-        try
-            _ = elvis_config:from_file(Filename),
-            fail
-        catch
-            _ ->
-                ok
-        after
-            file:delete(Filename)
-        end.
+    {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(Filename),
+    _ = file:delete(Filename).
 
 find_file_and_check_src(_Config) ->
     Dirs = ["../../test/examples"],

From b08309da69edd0cee248b290ef955afdf14f0edb Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 22:38:13 +0100
Subject: [PATCH 33/67] Have `elvis_core on elvis_core` work

---
 elvis.config       | 10 ++++++++--
 src/elvis_core.erl | 18 +++++++++---------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/elvis.config b/elvis.config
index c8e15c05..741c0b39 100644
--- a/elvis.config
+++ b/elvis.config
@@ -14,7 +14,11 @@
                         }},
                         {elvis_style, dont_repeat_yourself, #{min_complexity => 20}},
                         {elvis_style, no_debug_call, #{
-                            ignore => [{elvis_result, print_item, 4}, {elvis_utils, do_output, 2}]
+                            ignore => [
+                                {elvis_result, print_item, 4},
+                                {elvis_utils, do_output, 2},
+                                {elvis_core, main, 1}
+                            ]
                         }},
                         {elvis_style, no_god_modules, #{ignore => [elvis_style]}},
                         {elvis_style, no_throw, disable},
@@ -41,7 +45,9 @@
                             ignore => [elvis_core, elvis_config]
                         }},
                         {elvis_style, dont_repeat_yourself, #{min_complexity => 20}},
-                        {elvis_style, no_debug_call, #{ignore => [elvis_result, elvis_utils]}},
+                        {elvis_style, no_debug_call, #{
+                            ignore => [elvis_result, elvis_utils, elvis_core]
+                        }},
                         {elvis_style, no_god_modules, #{ignore => [elvis_style]}},
                         {elvis_style, no_throw, disable},
                         {elvis_style, no_common_caveats_call, disable}
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index 0e055c43..fbe79f35 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -4,6 +4,8 @@
 
 -export([rock/1, rock_this/2]).
 -export([start/0]).
+%% for internal use only
+-export([do_rock/2]).
 %% for eating our own dogfood
 -export([main/1]).
 
@@ -11,14 +13,16 @@
 
 -ifdef(TEST).
 
--export([do_rock/2, apply_rule/2]).
+-export([apply_rule/2]).
 % For tests (we can't Xref the tests because rebar3 fails to compile some files).
--ignore_xref([do_rock/2, apply_rule/2]).
+-ignore_xref([apply_rule/2]).
 
 -endif.
 
 % For eating our own dogfood.
 -ignore_xref([main/1]).
+% For internal use only
+-ignore_xref([do_rock/2]).
 % For shell usage.
 -ignore_xref([start/0]).
 % API exports, not consumed locally.
@@ -37,7 +41,7 @@ start() ->
     {ok, _} = application:ensure_all_started(elvis_core),
     ok.
 
-validate_config_or_throw(ElvisConfig) ->
+validate_config(ElvisConfig) ->
     try elvis_config:validate_config(ElvisConfig) of
         ok ->
             ok
@@ -51,7 +55,7 @@ validate_config_or_throw(ElvisConfig) ->
 -spec rock([elvis_config:t()]) ->
     ok | {fail, [{throw, term()} | elvis_result:file() | elvis_result:rule()]}.
 rock(ElvisConfig) ->
-    case validate_config_or_throw(ElvisConfig) of
+    case validate_config(ElvisConfig) of
         ok ->
             elvis_ruleset:dump_custom(),
             Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
@@ -67,7 +71,7 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
     Path = proplists:get_value(source, ModuleInfo),
     rock_this(Path, ElvisConfig);
 rock_this(Path, ElvisConfig) ->
-    case validate_config_or_throw(ElvisConfig) of
+    case validate_config(ElvisConfig) of
         ok ->
             elvis_ruleset:dump_custom(),
             Dirname = filename:dirname(Path),
@@ -131,8 +135,6 @@ do_parallel_rock(ElvisConfig0) ->
             {fail, [{T, E}]}
     end.
 
--ifdef(TEST).
-
 -spec do_rock(elvis_file:t(), [elvis_config:t()] | elvis_config:t()) ->
     {ok, elvis_result:file()}.
 do_rock(File, ElvisConfig) ->
@@ -140,8 +142,6 @@ do_rock(File, ElvisConfig) ->
     Results = apply_rules(ElvisConfig, LoadedFile),
     {ok, Results}.
 
--endif.
-
 -spec load_file_data([elvis_config:t()] | elvis_config:t(), elvis_file:t()) ->
     elvis_file:t().
 load_file_data(ElvisConfig, File) ->

From 76328fb6a8afe8ad440fe6feb497de4637b9f22d Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 23:43:44 +0100
Subject: [PATCH 34/67] Re-read README and act on expected output

Only do color parsing after creating the expected output
---
 README.md             | 17 +++++------------
 elvis.config          |  3 +--
 src/elvis_code.erl    |  2 +-
 src/elvis_config.erl  | 25 +++++++++++--------------
 src/elvis_core.erl    |  6 +++---
 src/elvis_result.erl  | 13 ++++++-------
 src/elvis_ruleset.erl |  2 +-
 src/elvis_utils.erl   | 27 +++++++++++++++++++++------
 8 files changed, 49 insertions(+), 46 deletions(-)

diff --git a/README.md b/README.md
index 9d05de76..bbe9433a 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,7 @@ Once this is done you can apply the style rules in the following ways.
 ```shell
 1> ElvisConfig = elvis_config:config().
 <loaded_config>
-2> elvis_core:rock(ElvisConfig).
+2> application:set_env(elvis_core, verbose, true), elvis_core:rock(ElvisConfig).
 Loading src/elvis_code.erl
 # src/elvis_code.erl [OK]
 Loading src/elvis_config.erl
@@ -68,18 +68,11 @@ Another option for using `elvis_core` from the shell is to explicitly provide th
 an argument to `elvis_core:rock/1`:
 
 ```shell
-1> ElvisConfig = [#{dirs => ["src"], filter => "*.erl", rules => []}].
+1> ElvisConfig = [#{dirs => ["src"], filter => "elvis_rule.erl", ruleset => erl_files}].
 [#{dirs => ["src"],filter => "*.erl",rules => []}]
-2> elvis_core:rock(ElvisConfig).
-Loading src/elvis_code.erl
-# src/elvis_code.erl [OK]
-Loading src/elvis_config.erl
-# src/elvis_config.erl [OK]
-Loading src/elvis_core.erl
-# src/elvis_core.erl [OK]
-Loading src/elvis_file.erl
-# src/elvis_file.erl [OK]
-...
+2> application:set_env(elvis_core, verbose, true), elvis_core:rock(ElvisConfig).
+Loading src/elvis_rule.erl
+# src/elvis_rule.erl [OK]
 ok
 3>
 ```
diff --git a/elvis.config b/elvis.config
index 741c0b39..2c3aece5 100644
--- a/elvis.config
+++ b/elvis.config
@@ -76,7 +76,6 @@
                         {elvis_style, atom_naming_convention, #{ignore => [style_SUITE]}}
                     ]
             }
-        ]},
-        {no_output, true}
+        ]}
     ]}
 ].
diff --git a/src/elvis_code.erl b/src/elvis_code.erl
index edfd4f7f..24400769 100644
--- a/src/elvis_code.erl
+++ b/src/elvis_code.erl
@@ -189,6 +189,6 @@ print_node(#{type := Type} = Node, CurrentLevel) ->
     Indentation = lists:duplicate(CurrentLevel * 4, $\s),
     Content = ktn_code:content(Node),
 
-    ok = elvis_utils:output(info, "~s - [~p] ~p~n", [Indentation, CurrentLevel, Type]),
+    ok = elvis_utils:info("~s - [~p] ~p~n", [Indentation, CurrentLevel, Type]),
     _ = lists:map(fun(Child) -> print_node(Child, CurrentLevel + 1) end, Content),
     ok.
diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 080e082a..1a135723 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -40,17 +40,17 @@ fetch_elvis_config(Key, AppConfig) ->
     Elvis.
 
 from_static(Key, {Type, Config}) ->
-    elvis_utils:output(debug, "fetching key ~p from ~p configuration", [Key, Type]),
+    elvis_utils:debug("fetching key ~p from ~p configuration", [Key, Type]),
     case proplists:get_value(Key, Config) of
         undefined ->
-            elvis_utils:output(
-                debug, "no value for key ~p found in ~p configuration; going with default", [
+            elvis_utils:debug(
+                "no value for key ~p found in ~p configuration; going with default", [
                     Key, Type
                 ]
             ),
             default(Key);
         Value ->
-            elvis_utils:output(debug, "value for key ~p found in ~p configuration", [Key, Type]),
+            elvis_utils:debug("value for key ~p found in ~p configuration", [Key, Type]),
             Value
     end.
 
@@ -72,14 +72,13 @@ parallel() ->
 default(Key) ->
     case application:get_env(elvis_core, Key) of
         undefined ->
-            elvis_utils:output(
-                debug,
+            elvis_utils:debug(
                 "no value for key ~p found in application environment; going with default",
                 [Key]
             ),
             default_for(Key);
         {ok, Value} ->
-            elvis_utils:output(debug, "value for key ~p found in application environment", [Key]),
+            elvis_utils:debug("value for key ~p found in application environment", [Key]),
             Value
     end.
 
@@ -89,9 +88,7 @@ for(Key) ->
         case consult_elvis_config("elvis.config") of
             AppDefault ->
                 % This might happen whether we fail to parse the file or it actually is []
-                elvis_utils:output(
-                    debug, "elvis.config unusable; falling back to rebar.config", []
-                ),
+                elvis_utils:debug("elvis.config unusable; falling back to rebar.config", []),
                 consult_rebar_config("rebar.config");
             AppConfig0 ->
                 AppConfig0
@@ -103,20 +100,20 @@ for(Key) ->
 consult_elvis_config(File) ->
     case file:consult(File) of
         {ok, [AppConfig]} ->
-            elvis_utils:output(debug, "elvis.config usable; using it", []),
+            elvis_utils:debug("elvis.config usable; using it", []),
             AppConfig;
         _ ->
-            elvis_utils:output(debug, "elvis.config unusable", []),
+            elvis_utils:debug("elvis.config unusable", []),
             default_for(app)
     end.
 
 consult_rebar_config(File) ->
     case file:consult(File) of
         {ok, AppConfig0} ->
-            elvis_utils:output(debug, "rebar.config usable; using it", []),
+            elvis_utils:debug("rebar.config usable; using it", []),
             AppConfig0;
         _ ->
-            elvis_utils:output(debug, "rebar.config unusable", []),
+            elvis_utils:debug("rebar.config unusable", []),
             default_for(app)
     end.
 
diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index fbe79f35..d42d2893 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -93,7 +93,7 @@ rock_this(Path, ElvisConfig) ->
                 end,
             case lists:filter(FilterFun, ElvisConfig) of
                 [] ->
-                    elvis_utils:output(info, "Skipping ~s", [Path]);
+                    elvis_utils:info("Skipping ~s", [Path]);
                 FilteredElvisConfig ->
                     LoadedFile = load_file_data(FilteredElvisConfig, File),
                     ApplyRulesFun = fun(Cfg) -> apply_rules_and_print(Cfg, LoadedFile) end,
@@ -146,13 +146,13 @@ do_rock(File, ElvisConfig) ->
     elvis_file:t().
 load_file_data(ElvisConfig, File) ->
     Path = elvis_file:path(File),
-    elvis_utils:output(info, "Loading ~s", [Path]),
+    elvis_utils:info("Loading ~s", [Path]),
     try
         elvis_file:load_file_data(ElvisConfig, File)
     catch
         _:Reason ->
             Msg = "~p when loading file ~p.",
-            elvis_utils:output(error, Msg, [Reason, Path]),
+            elvis_utils:error(Msg, [Reason, Path]),
             File
     end.
 
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index c9901aa4..711ede46 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -187,9 +187,9 @@ print(Format, #{file := Path, rules := Rules}) ->
         _ ->
             case status(Rules) of
                 ok ->
-                    elvis_utils:output(notice, "# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
+                    elvis_utils:notice("# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
                 fail ->
-                    elvis_utils:output(error, "# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
+                    elvis_utils:error("# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
             end
     end,
     print_rules(Format, Path, Rules);
@@ -216,8 +216,7 @@ print_rules(
         parsable ->
             ok;
         _ ->
-            elvis_utils:output(
-                error,
+            elvis_utils:error(
                 "  - ~p "
                 "(https://github.com/inaka/elvis_core/tree/main/doc_rules/~p/~p.md)",
                 [Name, Scope, Name]
@@ -249,7 +248,7 @@ print_item(
             FMsg = io_lib:format(Msg, Info),
             io:format("~s:~p:~p:~s~n", [File, Ln, Name, FMsg]);
         _ ->
-            elvis_utils:output(error, "    - " ++ Msg, Info)
+            elvis_utils:error("    - " ++ Msg, Info)
     end,
     print_item(Format, File, Name, Items);
 print_item(Format, File, Name, [Error | Items]) ->
@@ -259,9 +258,9 @@ print_item(_Format, _File, _Name, []) ->
     ok.
 
 print_error(#{error_msg := Msg, info := Info}) ->
-    elvis_utils:output(error, Msg, Info);
+    elvis_utils:error(Msg, Info);
 print_error(#{warn_msg := Msg, info := Info}) ->
-    elvis_utils:output(warn, Msg, Info).
+    elvis_utils:warn(Msg, Info).
 
 -spec status([file() | rule()]) -> ok | fail.
 status([]) ->
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index f80f280d..2dbd0a9b 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -9,7 +9,7 @@ load_custom(Rulesets) ->
     {Existed, Tid} = ensure_table(),
     case Existed of
         false ->
-            elvis_utils:output(debug, "loading custom rulesets into state", []),
+            elvis_utils:debug("loading custom rulesets into state", []),
             lists:foreach(
                 fun({Ruleset, NSNameDefs}) ->
                     Rules = [elvis_rule:from_tuple(NSNameDef) || NSNameDef <- NSNameDefs],
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 4b234e2c..6ab9e8fe 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -5,7 +5,7 @@
 %% General
 -export([erlang_halt/1, to_str/1, split_all_lines/1, split_all_lines/2]).
 %% Output / rebar3
--export([output/3, abort/2]).
+-export([debug/2, info/2, notice/2, warn/2, error/2, abort/2]).
 
 % These call (but verify if exported) rebar3-specific functions.
 -ignore_xref(do_output/2).
@@ -73,6 +73,21 @@ escape_chars(String) ->
     ResultBin = iolist_to_binary(Result),
     binary_to_list(ResultBin).
 
+debug(Format, Data) ->
+    output(debug, "Elvis: " ++ Format, Data).
+
+info(Format, Data) ->
+    output(info, Format ++ "{{reset}}~n", Data).
+
+notice(Format, Data) ->
+    output(notice, "{{white-bold}}" ++ Format ++ "{{reset}}~n", Data).
+
+warn(Format, Data) ->
+    output(warn, "{{magenta}}Warning: {{reset}}" ++ Format ++ "{{reset}}~n", Data).
+
+error(Format, Data) ->
+    output(error, "{{red}}Error: {{reset}}" ++ Format ++ "{{reset}}~n", Data).
+
 -spec output(debug | info | notice | warn | error, Format :: io:format(), Data :: [term()]) -> ok.
 output(debug = _Type, Format, Data) ->
     Chars = io_lib:format(Format, Data),
@@ -92,28 +107,28 @@ output(Type, Format, Data) ->
 do_output(debug, Chars) ->
     case erlang:function_exported(rebar_api, debug, 2) of
         true ->
-            rebar_api:debug("Elvis: " ++ Chars, []);
+            rebar_api:debug(Chars, []);
         false ->
             ok
     end;
 do_output(info, Chars) ->
     case elvis_config:verbose() of
         true ->
-            io:format(Chars ++ "{{reset}}~n");
+            io:format(Chars);
         false ->
             ok
     end;
 do_output(notice, Chars) ->
     case elvis_config:verbose() of
         true ->
-            io:format("{{white-bold}}" ++ Chars ++ "{{reset}}~n");
+            io:format(Chars);
         false ->
             ok
     end;
 do_output(warn, Chars) ->
-    io:format("{{magenta}}Warning: {{reset}}" ++ Chars ++ "{{reset}}~n");
+    io:format(Chars);
 do_output(error, Chars) ->
-    io:format("{{red}}Error: {{reset}}" ++ Chars ++ "{{reset}}~n").
+    io:format(Chars).
 
 -dialyzer({nowarn_function, abort/2}).
 -spec abort(Format :: io:format(), Data :: [term()]) -> no_return().

From 2b0ba4bb7cae2e6f0703d8c4f8ae180d6857e127 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 23:50:22 +0100
Subject: [PATCH 35/67] Don't change if we don't have to

---
 rebar.config | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/rebar.config b/rebar.config
index 4b0cf02c..08cb04ee 100644
--- a/rebar.config
+++ b/rebar.config
@@ -22,9 +22,7 @@
     ]}
 ]}.
 
-{alias, [
-    {test, [compile, fmt, hank, xref, dialyzer, ct, cover, ex_doc]}
-]}.
+{alias, [{test, [compile, fmt, hank, xref, dialyzer, ct, cover, ex_doc]}]}.
 
 {shell, [{config, "config/test.config"}]}.
 

From 39d3cbe6eb8ace208a8fb99a6d82d652d38e3025 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 23:56:01 +0100
Subject: [PATCH 36/67] Rename it for clarity

---
 src/elvis_core.erl    | 4 ++--
 src/elvis_ruleset.erl | 4 ++--
 test/elvis_SUITE.erl  | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index d42d2893..a43d5125 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -57,7 +57,7 @@ validate_config(ElvisConfig) ->
 rock(ElvisConfig) ->
     case validate_config(ElvisConfig) of
         ok ->
-            elvis_ruleset:dump_custom(),
+            elvis_ruleset:drop_custom(),
             Results = lists:map(fun do_parallel_rock/1, ElvisConfig),
             lists:foldl(fun combine_results/2, ok, Results);
         {error, Error} ->
@@ -73,7 +73,7 @@ rock_this(Module, ElvisConfig) when is_atom(Module) ->
 rock_this(Path, ElvisConfig) ->
     case validate_config(ElvisConfig) of
         ok ->
-            elvis_ruleset:dump_custom(),
+            elvis_ruleset:drop_custom(),
             Dirname = filename:dirname(Path),
             Filename = filename:basename(Path),
             File =
diff --git a/src/elvis_ruleset.erl b/src/elvis_ruleset.erl
index 2dbd0a9b..80b059b5 100644
--- a/src/elvis_ruleset.erl
+++ b/src/elvis_ruleset.erl
@@ -2,7 +2,7 @@
 
 -format(#{inline_items => none}).
 
--export([rules/1, load_custom/1, dump_custom/0, is_defined/1, custom_names/0]).
+-export([rules/1, load_custom/1, drop_custom/0, is_defined/1, custom_names/0]).
 
 -spec load_custom(#{atom() => list()}) -> ok.
 load_custom(Rulesets) ->
@@ -29,7 +29,7 @@ custom_names() ->
             proplists:get_keys(ets:tab2list(elvis_ruleset))
     end.
 
-dump_custom() ->
+drop_custom() ->
     case table_exists() of
         false ->
             ok;
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 85f77f97..204df707 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -330,7 +330,7 @@ custom_ruleset(_Config) ->
     [[NoTabs]] = elvis_config:rules(ElvisConfig),
 
     %% this is also done by :rock and :rock_this
-    _ = elvis_ruleset:dump_custom(),
+    _ = elvis_ruleset:drop_custom(),
 
     %% read unknown ruleset configuration to ensure rulesets from
     %% previous load do not stick around

From 85d72d7a8fe391a3c78a49785d77384c46d6e6fb Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 16 Jul 2025 23:59:34 +0100
Subject: [PATCH 37/67] Use it if available, and drop custom ignore_xref

---
 src/elvis_core.erl  | 2 +-
 src/elvis_utils.erl | 3 ---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index a43d5125..b177ffe6 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -162,7 +162,7 @@ main([]) ->
     {module, _} = code:ensure_loaded(elvis_style),
     case rock(elvis_config:config()) of
         ok -> true;
-        _ -> halt(1)
+        _ -> elvis_utils:erlang_halt(1)
     end.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 6ab9e8fe..080d08a9 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -11,9 +11,6 @@
 -ignore_xref(do_output/2).
 -ignore_xref(abort/2).
 
-% API exports, not consumed locally.
--ignore_xref([erlang_halt/1]).
-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Public
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

From 7cb4cc70a254c16dcf903c906215917ae9981970 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 00:25:01 +0100
Subject: [PATCH 38/67] Spec it for consumption

---
 src/elvis_config.erl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 1a135723..86dda3ed 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -117,10 +117,12 @@ consult_rebar_config(File) ->
             default_for(app)
     end.
 
+-spec from_rebar(File :: string()) -> t().
 from_rebar(File) ->
     AppConfig = consult_rebar_config(File),
     fetch_elvis_config_from(AppConfig).
 
+-spec from_file(File :: string()) -> t().
 from_file(File) ->
     AppConfig = consult_elvis_config(File),
     fetch_elvis_config_from(AppConfig).

From 961d118fc4154bf86250f824ad02c56aa0cd67cc Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 00:25:32 +0100
Subject: [PATCH 39/67] Add convenience elvis_config API

---
 src/elvis_config.erl | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 86dda3ed..57c756fe 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -12,6 +12,7 @@
 
 %% Options
 -export([config/0, output_format/0, verbose/0, no_output/0, parallel/0]).
+-export([set_output_format/1, set_verbose/1, set_no_output/1, set_parallel/1]).
 
 % Corresponds to the 'config' key.
 -type t() :: map().
@@ -22,6 +23,7 @@
 
 % API exports, not consumed locally.
 -ignore_xref([from_rebar/1, from_file/1, default/0, resolve_files/2, apply_to_files/2]).
+-ignore_xref([set_output_format/1, set_verbose/1, set_no_output/1, set_parallel/1]).
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%% Public
@@ -69,6 +71,21 @@ no_output() ->
 parallel() ->
     for(parallel).
 
+set_output_format(OutputFormat) ->
+    set_env(output_format, OutputFormat).
+
+set_verbose(Verbose) ->
+    set_env(verbose, Verbose).
+
+set_no_output(NoOutput) ->
+    set_env(no_output, NoOutput).
+
+set_parallel(Parallel) ->
+    set_env(parallel, Parallel).
+
+set_env(Key, Value) ->
+    application:set_env(elvis_core, Key, Value).
+
 default(Key) ->
     case application:get_env(elvis_core, Key) of
         undefined ->

From 9e3c7ef38f6ae97d578f67554f18ba39844cd85e Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 00:39:34 +0100
Subject: [PATCH 40/67] Fix default configuration

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 57c756fe..9938ac77 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -198,7 +198,7 @@ default() ->
                 "apps/**/include/**",
                 "include/**"
             ],
-            filter => "*.erl",
+            filter => "*.hrl",
             ruleset => hrl_files
         },
         #{

From 1767ba451fd2197fe91cdf1b64c6887af9d8cd81 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 00:43:29 +0100
Subject: [PATCH 41/67] Add a note on default configuration to the README

---
 README.md | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/README.md b/README.md
index bbe9433a..eaac8e7d 100644
--- a/README.md
+++ b/README.md
@@ -123,6 +123,32 @@ An `elvis.config` file looks something like this:
 ]}].
 ```
 
+To look at what is considered the "current default" configuration, do:
+
+```console
+rebar3 shell
+...
+1> elvis_config:default().
+[#{filter => "*.erl",
+   dirs => ["apps/**/src/**","src/**"],
+   ruleset => erl_files},
+ #{filter => "*.erl",
+   dirs =>
+       ["apps/**/src/**","src/**","apps/**/include/**",
+        "include/**"],
+   ruleset => hrl_files},
+ #{filter => "rebar.config",
+   dirs => ["."],
+   ruleset => rebar_config},
+ #{filter => ".gitignore",
+   dirs => ["."],
+   ruleset => gitignore}]
+2>
+```
+
+**Note**: this element might change with time. The above was what was generated when this
+documentation was updated.
+
 ### Files, rules and rulesets
 
 The `dirs` key is a list that tells `elvis_core` where it should look for the files that match

From 797de2b1a295af3d026b72e43ee07838476bd1b0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 02:12:34 +0100
Subject: [PATCH 42/67] Make for easier-to-follow output

---
 src/elvis_config.erl | 84 +++++++++++++++++++++++---------------------
 1 file changed, 44 insertions(+), 40 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 9938ac77..5a424fba 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -42,17 +42,17 @@ fetch_elvis_config(Key, AppConfig) ->
     Elvis.
 
 from_static(Key, {Type, Config}) ->
-    elvis_utils:debug("fetching key ~p from ~p configuration", [Key, Type]),
+    elvis_utils:debug("fetching key '~s' from '~s' configuration", [Key, Type]),
     case proplists:get_value(Key, Config) of
         undefined ->
             elvis_utils:debug(
-                "no value for key ~p found in ~p configuration; going with default", [
+                "no value for key '~s' found in '~s' configuration; going with default", [
                     Key, Type
                 ]
             ),
             default(Key);
         Value ->
-            elvis_utils:debug("value for key ~p found in ~p configuration", [Key, Type]),
+            elvis_utils:debug("value for key '~s' found in '~s' configuration", [Key, Type]),
             Value
     end.
 
@@ -90,12 +90,12 @@ default(Key) ->
     case application:get_env(elvis_core, Key) of
         undefined ->
             elvis_utils:debug(
-                "no value for key ~p found in application environment; going with default",
+                "no value for key '~s' found in application environment; going with default",
                 [Key]
             ),
             default_for(Key);
         {ok, Value} ->
-            elvis_utils:debug("value for key ~p found in application environment", [Key]),
+            elvis_utils:debug("value for key '~s' found in application environment", [Key]),
             Value
     end.
 
@@ -134,12 +134,12 @@ consult_rebar_config(File) ->
             default_for(app)
     end.
 
--spec from_rebar(File :: string()) -> t().
+-spec from_rebar(File :: string()) -> [t()].
 from_rebar(File) ->
     AppConfig = consult_rebar_config(File),
     fetch_elvis_config_from(AppConfig).
 
--spec from_file(File :: string()) -> t().
+-spec from_file(File :: string()) -> [t()].
 from_file(File) ->
     AppConfig = consult_elvis_config(File),
     fetch_elvis_config_from(AppConfig).
@@ -381,26 +381,26 @@ do_validate({elvis = Option, Elvis}) ->
         _ ->
             maybe
                 ok = flag(validation_started(Option)),
-                ok ?= is_nonempty_list("elvis", Elvis),
+                ok ?= is_nonempty_list(elvis, Elvis),
                 ok ?=
                     proplist_keys_are_in(
-                        "elvis", Elvis, elvis_control_opts() ++ [rulesets, config]
+                        'elvis', Elvis, elvis_control_opts() ++ [rulesets, config]
                     ),
                 OutputFormat = get_elvis_opt(output_format, Elvis),
-                ok ?= is_one_of("elvis.output_format", OutputFormat, [colors, plain, parsable]),
+                ok ?= is_one_of('elvis.output_format', OutputFormat, [colors, plain, parsable]),
                 Verbose = get_elvis_opt(verbose, Elvis),
-                ok ?= is_boolean("elvis.verbose", Verbose),
+                ok ?= is_boolean('elvis.verbose', Verbose),
                 NoOutput = get_elvis_opt(no_output, Elvis),
-                ok ?= is_boolean("elvis.no_output", NoOutput),
+                ok ?= is_boolean('elvis.no_output', NoOutput),
                 Parallel = get_elvis_opt(parallel, Elvis),
-                ok ?= is_pos_integer("elvis.parallel", Parallel),
+                ok ?= is_pos_integer('elvis.parallel', Parallel),
                 CustomRulesets = get_elvis_opt(rulesets, Elvis),
-                ok ?= are_valid_rulesets("elvis.rulesets", CustomRulesets),
+                ok ?= are_valid_rulesets('elvis.rulesets', CustomRulesets),
                 ElvisConfig = get_elvis_opt(config, Elvis),
-                ok ?= is_valid_config("elvis.config", maps:keys(CustomRulesets), ElvisConfig)
+                ok ?= is_valid_config('elvis.config', maps:keys(CustomRulesets), ElvisConfig)
             else
                 {error, FormatData} ->
-                    do_validate_results(FormatData)
+                    do_validate_throw(FormatData)
             end
     end;
 do_validate({config = Option, ElvisConfig}) ->
@@ -409,15 +409,15 @@ do_validate({config = Option, ElvisConfig}) ->
             ok;
         _ ->
             maybe
-                ok ?= is_valid_config("elvis.config", elvis_ruleset:custom_names(), ElvisConfig)
+                ok ?= is_valid_config('elvis.config', elvis_ruleset:custom_names(), ElvisConfig)
             else
                 {error, FormatData} ->
-                    do_validate_results(FormatData)
+                    do_validate_throw(FormatData)
             end
     end.
 
--spec do_validate_results(_) -> no_return().
-do_validate_results(FormatData) ->
+-spec do_validate_throw(_) -> no_return().
+do_validate_throw(FormatData) ->
     {Format, Data} =
         case is_list(FormatData) of
             false ->
@@ -431,7 +431,7 @@ do_validate_results(FormatData) ->
     throw({invalid_config, io_lib:format(Format, Data)}).
 
 is_nonempty_list(What, List) when not is_list(List) orelse List =:= [] ->
-    {error, {"~p is expected to be a non-empty list.", [What]}};
+    {error, {"'~s' is expected to be a non-empty list.", [What]}};
 is_nonempty_list(_What, _List) ->
     ok.
 
@@ -441,7 +441,7 @@ proplist_keys_are_in(What, List, Keys) ->
         [] ->
             ok;
         _ ->
-            {error, {"in ~p, the following keys are unknown: ~p.", [What, Filtered]}}
+            {error, {"in '~s', the following keys are unknown: ~p.", [What, Filtered]}}
     end.
 
 is_one_of(What, Value, Possibilities) ->
@@ -449,18 +449,18 @@ is_one_of(What, Value, Possibilities) ->
         true ->
             ok;
         _ ->
-            {error, {"~p is expected to be one of the following: ~p.", [What, Possibilities]}}
+            {error, {"'~s' is expected to be one of the following: ~p.", [What, Possibilities]}}
     end.
 
 is_boolean(_What, Value) when is_boolean(Value) ->
     ok;
 is_boolean(What, _Value) ->
-    {error, {"~p is expected to be a boolean.", [What]}}.
+    {error, {"'~s' is expected to be a boolean.", [What]}}.
 
 is_pos_integer(_What, Value) when is_integer(Value) andalso Value > 0 ->
     ok;
 is_pos_integer(What, _Value) ->
-    {error, {"~p is expected to be a positive integer.", [What]}}.
+    {error, {"'~s' is expected to be a positive integer.", [What]}}.
 
 are_valid_rulesets(What, CustomRulesets) ->
     maybe
@@ -476,7 +476,7 @@ are_valid_rulesets(What, CustomRulesets) ->
 is_map(_What, Value) when is_map(Value) ->
     ok;
 is_map(What, _Value) ->
-    {error, {"~p is expected to be a map.", [What]}}.
+    {error, {"'~s' is expected to be a map.", [What]}}.
 
 all_map_keys_are_atoms(What, Map) ->
     Filtered = [Key || Key <- maps:keys(Map), not is_atom(Key)],
@@ -484,7 +484,7 @@ all_map_keys_are_atoms(What, Map) ->
         [] ->
             ok;
         _ ->
-            {error, {"in ~p, keys are expected to be atoms.", [What]}}
+            {error, {"in '~s', keys are expected to be atoms.", [What]}}
     end.
 
 all_custom_rulesets_have_valid_rules(What, CustomRulesets) ->
@@ -497,7 +497,7 @@ all_custom_rulesets_have_valid_rules(What, CustomRulesets) ->
                             AccInI;
                         {false, ValidError} ->
                             [
-                                {"in ~p, in ruleset ~p, " ++ ValidError, [What, CustomRuleset]}
+                                {"in '~s', in ruleset '~s', " ++ ValidError, [What, CustomRuleset]}
                                 | AccInI
                             ]
                     end
@@ -527,7 +527,7 @@ no_default_ruleset_override(What, CustomRulesets) ->
         _ ->
             {error,
                 {
-                    "in ~p, the following rulesets are not expected to be "
+                    "in '~s', the following rulesets are not expected to be "
                     "named after a default ruleset: ~p.",
                     [
                         What, Filtered
@@ -559,7 +559,9 @@ all_configs_are_valid(What, CustomRulesetNames, Configset) ->
                         AccIn;
                     {error, ValidError} ->
                         [
-                            {"in ~p, at list position number ~p, " ++ ValidError, [What, PosNumber]}
+                            {"in '~s', at list position number ~p, " ++ ValidError, [
+                                What, PosNumber
+                            ]}
                             | AccIn
                         ]
                 end,
@@ -608,7 +610,7 @@ map_keys_are_in(Map, Keys) ->
     end.
 
 is_nonempty_list_of_dirs(What, List) when not is_list(List) orelse List =:= [] ->
-    {error, io_lib:format("~p is expected to be a non-empty list.", [What])};
+    {error, io_lib:format("'~s' is expected to be a non-empty list.", [What])};
 is_nonempty_list_of_dirs(What, List) ->
     Filtered = [
         Element
@@ -620,7 +622,7 @@ is_nonempty_list_of_dirs(What, List) ->
         _ ->
             {error,
                 io_lib:format(
-                    "in ~p, the following elements are not (or don't contain) directories: ~p.",
+                    "in '~s', the following elements are not (or don't contain) directories: ~p.",
                     [What, Filtered]
                 )}
     end.
@@ -635,7 +637,7 @@ is_nonempty_string(What, String) ->
         true ->
             ok;
         _ ->
-            {error, io_lib:format("~p is expected to be a non-empty string.", [What])}
+            {error, io_lib:format("'~s' is expected to be a non-empty string.", [What])}
     end.
 
 all_dirs_filter_combos_are_valid(Dirs, Filter) ->
@@ -646,9 +648,11 @@ all_dirs_filter_combos_are_valid(Dirs, Filter) ->
                     AccIn;
                 _ ->
                     [
-                        io_lib:format("dir + filter combo ~p + ~p yielded no files to analyse.", [
+                        io_lib:format(
+                            "'<dir>' + '<filter>' combo '~s' + '~s' yielded no files to analyse.", [
                             Dir, Filter
-                        ])
+                            ]
+                        )
                         | AccIn
                     ]
             end
@@ -664,7 +668,7 @@ all_dirs_filter_combos_are_valid(Dirs, Filter) ->
     end.
 
 is_list_of_ignorables(What, List) when not is_list(List) ->
-    {error, io_lib:format("~p is expected to be a list.", [What])};
+    {error, io_lib:format("'~s' is expected to be a list.", [What])};
 is_list_of_ignorables(What, List) ->
     Filtered = [Element || Element <- List, not elvis_rule:is_ignorable(Element)],
     case Filtered of
@@ -672,7 +676,7 @@ is_list_of_ignorables(What, List) ->
             ok;
         _ ->
             {error,
-                io_lib:format("in ~p, the following elements are not ignorable: ~p.", [
+                io_lib:format("in '~s', the following elements are not ignorable: ~p.", [
                     What, Filtered
                 ])}
     end.
@@ -685,13 +689,13 @@ defined_ruleset_is_custom_or_default(CustomRulesetNames, Ruleset) ->
             ok;
         _ ->
             {error,
-                io_lib:format("~p is expected to be either a custom or a default ruleset.", [
+                io_lib:format("'~s' is expected to be either a custom or a default ruleset.", [
                     Ruleset
                 ])}
     end.
 
 all_rules_are_valid(What, RuleTuples) when not is_list(RuleTuples) ->
-    {error, io_lib:format("~p is expected to be a list.", [What])};
+    {error, io_lib:format("'~s' is expected to be a list.", [What])};
 all_rules_are_valid(What, RuleTuples) ->
     AccOut = lists:foldl(
         fun(RuleTuple, AccInI) ->
@@ -699,7 +703,7 @@ all_rules_are_valid(What, RuleTuples) ->
                 {true, Rule} ->
                     check_rule_for_options(Rule, AccInI);
                 {false, ValidError} ->
-                    [io_lib:format("in ~p, " ++ ValidError, [What]) | AccInI]
+                    [io_lib:format("in '~s', " ++ ValidError, [What]) | AccInI]
             end
         end,
         [],

From d839029967eb2af11ce61fa8f00f31b6f4a84080 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:20:33 +0100
Subject: [PATCH 43/67] Adapt new entrypoint

---
 src/elvis_config.erl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 5a424fba..329adedc 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -57,7 +57,12 @@ from_static(Key, {Type, Config}) ->
     end.
 
 config() ->
-    for(config).
+    try
+        for(config)
+    catch
+        {invalid_config, _} = Caught ->
+            {fail, [{throw, Caught}]}
+    end.
 
 output_format() ->
     for(output_format).

From adf86c25799caf0aeb014bb3cd661c161be161f9 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:20:45 +0100
Subject: [PATCH 44/67] Adapt to Elvis (temporarily?)

---
 src/elvis_config.erl | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 329adedc..a949e3ad 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -587,7 +587,10 @@ get_config_opt(OptName, Config) ->
 
 config_is_valid(CustomRulesetNames, Config) ->
     maybe
-        ok ?= map_keys_are_in(Config, [dirs, filter, ignore, ruleset, rules]),
+        % We're keeping files, for the time being, because of elvis
+        % and the fact it knows about elvis_core's internals, but we
+        % should shortly revisit this
+        ok ?= map_keys_are_in(Config, [dirs, filter, ignore, ruleset, rules, files]),
         Dirs = get_config_opt(dirs, Config),
         ok ?= is_nonempty_list_of_dirs(dirs, Dirs),
         Filter = get_config_opt(filter, Config),
@@ -655,7 +658,7 @@ all_dirs_filter_combos_are_valid(Dirs, Filter) ->
                     [
                         io_lib:format(
                             "'<dir>' + '<filter>' combo '~s' + '~s' yielded no files to analyse.", [
-                            Dir, Filter
+                                Dir, Filter
                             ]
                         )
                         | AccIn

From 7afc514b4e3a9361c82f587c8a5a687bf80d3fb2 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:26:27 +0100
Subject: [PATCH 45/67] Fix API per consumption

---
 src/elvis_config.erl | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index a949e3ad..db581309 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -18,8 +18,8 @@
 -type t() :: map().
 -export_type([t/0]).
 
--type elvis() :: proplists:proplist().
--export_type([elvis/0]).
+-type fail_validation() :: {fail, [{throw, {invalid_config, Message :: string()}}]}.
+-export_type([fail_validation/0]).
 
 % API exports, not consumed locally.
 -ignore_xref([from_rebar/1, from_file/1, default/0, resolve_files/2, apply_to_files/2]).
@@ -56,6 +56,7 @@ from_static(Key, {Type, Config}) ->
             Value
     end.
 
+-spec config() -> [t()] | fail_validation().
 config() ->
     try
         for(config)
@@ -139,12 +140,12 @@ consult_rebar_config(File) ->
             default_for(app)
     end.
 
--spec from_rebar(File :: string()) -> [t()].
+-spec from_rebar(File :: string()) -> [t()] | fail_validation().
 from_rebar(File) ->
     AppConfig = consult_rebar_config(File),
     fetch_elvis_config_from(AppConfig).
 
--spec from_file(File :: string()) -> [t()].
+-spec from_file(File :: string()) -> [t()] | fail_validation().
 from_file(File) ->
     AppConfig = consult_elvis_config(File),
     fetch_elvis_config_from(AppConfig).

From a7d49d7c4aefd4c970d053fa0dc5f1385dba08ca Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:26:37 +0100
Subject: [PATCH 46/67] Act on dogfooding

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index db581309..8e76b2c2 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -390,7 +390,7 @@ do_validate({elvis = Option, Elvis}) ->
                 ok ?= is_nonempty_list(elvis, Elvis),
                 ok ?=
                     proplist_keys_are_in(
-                        'elvis', Elvis, elvis_control_opts() ++ [rulesets, config]
+                        elvis, Elvis, elvis_control_opts() ++ [rulesets, config]
                     ),
                 OutputFormat = get_elvis_opt(output_format, Elvis),
                 ok ?= is_one_of('elvis.output_format', OutputFormat, [colors, plain, parsable]),

From ae1bd21a79fe4971e2394ccc652f197c6cdb8f94 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:50:34 +0100
Subject: [PATCH 47/67] Typo

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index eaac8e7d..8816c27c 100644
--- a/README.md
+++ b/README.md
@@ -269,7 +269,7 @@ found in this repository's [RULES.md](https://github.com/inaka/elvis_core/blob/m
 The implementation of a new rule is a function that takes 2 arguments in the following order:
 
 1. `t:elvis_rule:t()`: the opaque rule to implement
-1. `t:elvis_config:config()`: the value of option `config` as found in the
+1. `t:elvis_config:t()`: the value of each element in list `config` as found in the
 [configuration](#configuration),
 
 This means you can define rules of your own (user-defined rules) as long as the functions that

From 3bb94bed35a99145b7aea13232947f4dd6bae4ae Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 03:50:52 +0100
Subject: [PATCH 48/67] Make it easier to follow

---
 src/elvis_config.erl | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 8e76b2c2..82adac13 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -123,20 +123,20 @@ for(Key) ->
 consult_elvis_config(File) ->
     case file:consult(File) of
         {ok, [AppConfig]} ->
-            elvis_utils:debug("elvis.config usable; using it", []),
+            elvis_utils:debug("elvis.config consultable; using it", []),
             AppConfig;
         _ ->
-            elvis_utils:debug("elvis.config unusable", []),
+            elvis_utils:debug("elvis.config unconsultable", []),
             default_for(app)
     end.
 
 consult_rebar_config(File) ->
     case file:consult(File) of
         {ok, AppConfig0} ->
-            elvis_utils:debug("rebar.config usable; using it", []),
+            elvis_utils:debug("rebar.config consultable; using it", []),
             AppConfig0;
         _ ->
-            elvis_utils:debug("rebar.config unusable", []),
+            elvis_utils:debug("rebar.config unconsultable", []),
             default_for(app)
     end.
 

From 39a4da277948f3b26973498840c315da5facf309 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 04:12:58 +0100
Subject: [PATCH 49/67] Add a bit more higher-level validation to proceed
 further

---
 src/elvis_config.erl | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 82adac13..e11958b2 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -122,7 +122,7 @@ for(Key) ->
 
 consult_elvis_config(File) ->
     case file:consult(File) of
-        {ok, [AppConfig]} ->
+        {ok, [AppConfig]} when is_list(AppConfig) ->
             elvis_utils:debug("elvis.config consultable; using it", []),
             AppConfig;
         _ ->
@@ -132,7 +132,7 @@ consult_elvis_config(File) ->
 
 consult_rebar_config(File) ->
     case file:consult(File) of
-        {ok, AppConfig0} ->
+        {ok, AppConfig0} when is_list(AppConfig0) ->
             elvis_utils:debug("rebar.config consultable; using it", []),
             AppConfig0;
         _ ->
@@ -437,7 +437,7 @@ do_validate_throw(FormatData) ->
     throw({invalid_config, io_lib:format(Format, Data)}).
 
 is_nonempty_list(What, List) when not is_list(List) orelse List =:= [] ->
-    {error, {"'~s' is expected to be a non-empty list.", [What]}};
+    {error, {"'~s' is expected to exist and be a non-empty list.", [What]}};
 is_nonempty_list(_What, _List) ->
     ok.
 

From 3ce87b321592ae92b73ed144b927760bb757995f Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 17 Jul 2025 23:00:57 +0100
Subject: [PATCH 50/67] Match on what we expect to

---
 src/elvis_core.erl | 5 ++---
 src/elvis_task.erl | 5 ++---
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/elvis_core.erl b/src/elvis_core.erl
index b177ffe6..dfebc526 100644
--- a/src/elvis_core.erl
+++ b/src/elvis_core.erl
@@ -42,9 +42,8 @@ start() ->
     ok.
 
 validate_config(ElvisConfig) ->
-    try elvis_config:validate_config(ElvisConfig) of
-        ok ->
-            ok
+    try
+        elvis_config:validate_config(ElvisConfig)
     catch
         {invalid_config, _} = Caught ->
             {error, {fail, [{throw, Caught}]}}
diff --git a/src/elvis_task.erl b/src/elvis_task.erl
index 102fbdc6..97b36b60 100644
--- a/src/elvis_task.erl
+++ b/src/elvis_task.erl
@@ -50,9 +50,8 @@ do_in_parallel(FunWork, FunAcc, ExtraArgs, List, MaxW, 0, AccR, AccG) ->
     do_in_parallel(FunWork, FunAcc, ExtraArgs, List, MaxW, erlang:min(N, MaxW), AccR1, AccG1);
 do_in_parallel(FunWork, FunAcc, ExtraArgs, List, MaxW, RemainW, AccR, AccG) ->
     {WorkToBeDone, WorkRemain} =
-        try lists:split(RemainW, List) of
-            Res ->
-                Res
+        try
+            lists:split(RemainW, List)
         catch
             error:badarg ->
                 {List, []}

From 00c9d8e6fe311c8bf9df5778476e60acf221d7cf Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 16:26:54 +0100
Subject: [PATCH 51/67] Make it prettier

---
 src/elvis_config.erl | 24 ++++++++++++------------
 src/elvis_utils.erl  | 16 +++++++++++++++-
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index e11958b2..c37563a0 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -447,7 +447,7 @@ proplist_keys_are_in(What, List, Keys) ->
         [] ->
             ok;
         _ ->
-            {error, {"in '~s', the following keys are unknown: ~p.", [What, Filtered]}}
+            {error, {"in '~s', the following keys are unknown: ~s.", [What, elvis_utils:list_to_str(Filtered)]}}
     end.
 
 is_one_of(What, Value, Possibilities) ->
@@ -455,7 +455,7 @@ is_one_of(What, Value, Possibilities) ->
         true ->
             ok;
         _ ->
-            {error, {"'~s' is expected to be one of the following: ~p.", [What, Possibilities]}}
+            {error, {"'~s' is expected to be one of the following: ~s.", [What, elvis_utils:list_to_str(Possibilities)]}}
     end.
 
 is_boolean(_What, Value) when is_boolean(Value) ->
@@ -534,9 +534,9 @@ no_default_ruleset_override(What, CustomRulesets) ->
             {error,
                 {
                     "in '~s', the following rulesets are not expected to be "
-                    "named after a default ruleset: ~p.",
+                    "named after a default ruleset: ~s.",
                     [
-                        What, Filtered
+                        What, elvis_utils:list_to_str(Filtered)
                     ]
                 }}
     end.
@@ -565,7 +565,7 @@ all_configs_are_valid(What, CustomRulesetNames, Configset) ->
                         AccIn;
                     {error, ValidError} ->
                         [
-                            {"in '~s', at list position number ~p, " ++ ValidError, [
+                            {"in '~s', at list position number ~w, " ++ ValidError, [
                                 What, PosNumber
                             ]}
                             | AccIn
@@ -615,7 +615,7 @@ map_keys_are_in(Map, Keys) ->
         [] ->
             ok;
         _ ->
-            {error, io_lib:format("the following keys are unknown: ~p.", [Filtered])}
+            {error, io_lib:format("the following keys are unknown: ~s.", [elvis_utils:list_to_str(Filtered)])}
     end.
 
 is_nonempty_list_of_dirs(What, List) when not is_list(List) orelse List =:= [] ->
@@ -631,8 +631,8 @@ is_nonempty_list_of_dirs(What, List) ->
         _ ->
             {error,
                 io_lib:format(
-                    "in '~s', the following elements are not (or don't contain) directories: ~p.",
-                    [What, Filtered]
+                    "in '~s', the following elements are not (or don't contain) directories: ~s.",
+                    [What, elvis_utils:list_to_str(Filtered)]
                 )}
     end.
 
@@ -685,8 +685,8 @@ is_list_of_ignorables(What, List) ->
             ok;
         _ ->
             {error,
-                io_lib:format("in '~s', the following elements are not ignorable: ~p.", [
-                    What, Filtered
+                io_lib:format("in '~s', the following elements are not ignorable: ~s.", [
+                    What, elvis_utils:list_to_str(Filtered)
                 ])}
     end.
 
@@ -748,8 +748,8 @@ check_rule_for_options(Rule, AccInI) ->
                 Extra ->
                     [
                         io_lib:format(
-                            "in rule ~p/~p, the following options are unknown: ~p.",
-                            [NS, Name, Extra]
+                            "in rule ~w/~w, the following options are unknown: ~s.",
+                            [NS, Name, elvis_utils:list_to_str(Extra)]
                         ),
                         AccInI
                     ]
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 080d08a9..f62efe12 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -3,7 +3,7 @@
 -compile({no_auto_import, [error/2]}).
 
 %% General
--export([erlang_halt/1, to_str/1, split_all_lines/1, split_all_lines/2]).
+-export([erlang_halt/1, list_to_str/1, to_str/1, split_all_lines/1, split_all_lines/2]).
 %% Output / rebar3
 -export([debug/2, info/2, notice/2, warn/2, error/2, abort/2]).
 
@@ -29,6 +29,20 @@ to_str(Arg) when is_integer(Arg) ->
 to_str(Arg) when is_list(Arg) ->
     Arg.
 
+list_to_str(What) ->
+    list_to_str(What, []).
+
+list_to_str([], Acc) ->
+    "[" ++ string:join(Acc, ", ") ++ "]";
+list_to_str([H0 | T], Acc) ->
+    H = case is_list(H0) of
+        true ->
+            "\"" ++ H0 ++ "\"";
+        _ ->
+            H0
+    end,
+    list_to_str(T, [to_str(H) | Acc]).
+
 -spec split_all_lines(binary()) -> [binary(), ...].
 split_all_lines(Binary) ->
     split_all_lines(Binary, []).

From 890e739588e7b6ca588e09d3ef99a153c67370f6 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 16:36:40 +0100
Subject: [PATCH 52/67] Tweak for a "better" default (?)

---
 src/elvis_config.erl | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index c37563a0..d114382c 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -191,18 +191,18 @@ default() ->
     [
         #{
             dirs => [
-                "apps/**/src/**",
-                "src/**"
+                "apps/**/src",
+                "src"
             ],
             filter => "*.erl",
             ruleset => erl_files
         },
         #{
             dirs => [
-                "apps/**/src/**",
-                "src/**",
-                "apps/**/include/**",
-                "include/**"
+                "apps/**/src",
+                "src",
+                "apps/**/include",
+                "include"
             ],
             filter => "*.hrl",
             ruleset => hrl_files

From 50f18398bfce20048bd8c3f99a0867bfc9fdbf10 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 16:50:09 +0100
Subject: [PATCH 53/67] Previous errors weren't actually `error`, but `notice`

---
 src/elvis_result.erl | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index 711ede46..55e95dae 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -189,7 +189,7 @@ print(Format, #{file := Path, rules := Rules}) ->
                 ok ->
                     elvis_utils:notice("# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
                 fail ->
-                    elvis_utils:error("# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
+                    elvis_utils:notice("# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
             end
     end,
     print_rules(Format, Path, Rules);
@@ -216,7 +216,7 @@ print_rules(
         parsable ->
             ok;
         _ ->
-            elvis_utils:error(
+            elvis_utils:notice(
                 "  - ~p "
                 "(https://github.com/inaka/elvis_core/tree/main/doc_rules/~p/~p.md)",
                 [Name, Scope, Name]
@@ -248,7 +248,7 @@ print_item(
             FMsg = io_lib:format(Msg, Info),
             io:format("~s:~p:~p:~s~n", [File, Ln, Name, FMsg]);
         _ ->
-            elvis_utils:error("    - " ++ Msg, Info)
+            elvis_utils:notice("    - " ++ Msg, Info)
     end,
     print_item(Format, File, Name, Items);
 print_item(Format, File, Name, [Error | Items]) ->

From d5c5ba13070c3946dc25e6cc78ded97266b442d7 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 17:48:31 +0100
Subject: [PATCH 54/67] Respect expected verbosity

---
 src/elvis_config.erl | 15 ++++++++++++---
 src/elvis_result.erl |  5 ++++-
 src/elvis_utils.erl  | 20 ++++++++------------
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index d114382c..32fe8724 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -447,7 +447,10 @@ proplist_keys_are_in(What, List, Keys) ->
         [] ->
             ok;
         _ ->
-            {error, {"in '~s', the following keys are unknown: ~s.", [What, elvis_utils:list_to_str(Filtered)]}}
+            {error,
+                {"in '~s', the following keys are unknown: ~s.", [
+                    What, elvis_utils:list_to_str(Filtered)
+                ]}}
     end.
 
 is_one_of(What, Value, Possibilities) ->
@@ -455,7 +458,10 @@ is_one_of(What, Value, Possibilities) ->
         true ->
             ok;
         _ ->
-            {error, {"'~s' is expected to be one of the following: ~s.", [What, elvis_utils:list_to_str(Possibilities)]}}
+            {error,
+                {"'~s' is expected to be one of the following: ~s.", [
+                    What, elvis_utils:list_to_str(Possibilities)
+                ]}}
     end.
 
 is_boolean(_What, Value) when is_boolean(Value) ->
@@ -615,7 +621,10 @@ map_keys_are_in(Map, Keys) ->
         [] ->
             ok;
         _ ->
-            {error, io_lib:format("the following keys are unknown: ~s.", [elvis_utils:list_to_str(Filtered)])}
+            {error,
+                io_lib:format("the following keys are unknown: ~s.", [
+                    elvis_utils:list_to_str(Filtered)
+                ])}
     end.
 
 is_nonempty_list_of_dirs(What, List) when not is_list(List) orelse List =:= [] ->
diff --git a/src/elvis_result.erl b/src/elvis_result.erl
index 55e95dae..4b64bf11 100644
--- a/src/elvis_result.erl
+++ b/src/elvis_result.erl
@@ -185,9 +185,12 @@ print(Format, #{file := Path, rules := Rules}) ->
         parsable ->
             ok;
         _ ->
+            Verbose = elvis_config:verbose(),
             case status(Rules) of
-                ok ->
+                ok when Verbose ->
                     elvis_utils:notice("# ~s [{{green-bold}}OK{{white-bold}}]", [Path]);
+                ok ->
+                    ok;
                 fail ->
                     elvis_utils:notice("# ~s [{{red-bold}}FAIL{{white-bold}}]", [Path])
             end
diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index f62efe12..8354f919 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -35,12 +35,13 @@ list_to_str(What) ->
 list_to_str([], Acc) ->
     "[" ++ string:join(Acc, ", ") ++ "]";
 list_to_str([H0 | T], Acc) ->
-    H = case is_list(H0) of
-        true ->
-            "\"" ++ H0 ++ "\"";
-        _ ->
-            H0
-    end,
+    H =
+        case is_list(H0) of
+            true ->
+                "\"" ++ H0 ++ "\"";
+            _ ->
+                H0
+        end,
     list_to_str(T, [to_str(H) | Acc]).
 
 -spec split_all_lines(binary()) -> [binary(), ...].
@@ -130,12 +131,7 @@ do_output(info, Chars) ->
             ok
     end;
 do_output(notice, Chars) ->
-    case elvis_config:verbose() of
-        true ->
-            io:format(Chars);
-        false ->
-            ok
-    end;
+    io:format(Chars);
 do_output(warn, Chars) ->
     io:format(Chars);
 do_output(error, Chars) ->

From 7fd248290ec76debaac0daa21c4e02cc60f873e5 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 17:48:42 +0100
Subject: [PATCH 55/67] Fix broken rule result

---
 src/elvis_project.erl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/elvis_project.erl b/src/elvis_project.erl
index eac8554a..66d9acaa 100644
--- a/src/elvis_project.erl
+++ b/src/elvis_project.erl
@@ -73,12 +73,12 @@ no_branch_deps(Rule, _ElvisConfig) ->
                 true ->
                     false;
                 false ->
-                    {true, [
+                    {true,
                         elvis_result:new_item(
                             "Dependency '~s' uses a branch; prefer a tag or a specific commit",
                             [AppName]
                         )
-                    ]}
+                    }
             end
         end,
         BadDeps

From d1b2e68878dc1b9ba198d91e72ccc613277e94c2 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 17:59:40 +0100
Subject: [PATCH 56/67] Adapt to actual usage

---
 src/elvis_utils.erl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index 8354f919..ebaf7105 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -139,10 +139,11 @@ do_output(error, Chars) ->
 
 -dialyzer({nowarn_function, abort/2}).
 -spec abort(Format :: io:format(), Data :: [term()]) -> no_return().
-abort(Format, Data) ->
+abort(Format0, Data) ->
+    Format = "Elvis: " ++ Format0 ++ "~n",
     case erlang:function_exported(rebar_api, abort, 2) of
         true ->
-            rebar_api:abort("Elvis: " ++ Format, [Data]);
+            rebar_api:abort(Format, [Data]);
         false ->
             output(error, Format, Data),
             throw(elvis_abort)

From 23a91f32bcc895b9b46fe7d409cd8e762cd9dab0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 18:00:54 +0100
Subject: [PATCH 57/67] rebar3 fmt it!

---
 src/elvis_project.erl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/elvis_project.erl b/src/elvis_project.erl
index 66d9acaa..a050b70a 100644
--- a/src/elvis_project.erl
+++ b/src/elvis_project.erl
@@ -77,8 +77,7 @@ no_branch_deps(Rule, _ElvisConfig) ->
                         elvis_result:new_item(
                             "Dependency '~s' uses a branch; prefer a tag or a specific commit",
                             [AppName]
-                        )
-                    }
+                        )}
             end
         end,
         BadDeps

From 8d4b07dd49b51620c617a85b09fc4acd2bd91f3f Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Mon, 21 Jul 2025 18:07:50 +0100
Subject: [PATCH 58/67] Remove extraneous ~n

---
 src/elvis_code.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_code.erl b/src/elvis_code.erl
index 24400769..a8bc8fc2 100644
--- a/src/elvis_code.erl
+++ b/src/elvis_code.erl
@@ -189,6 +189,6 @@ print_node(#{type := Type} = Node, CurrentLevel) ->
     Indentation = lists:duplicate(CurrentLevel * 4, $\s),
     Content = ktn_code:content(Node),
 
-    ok = elvis_utils:info("~s - [~p] ~p~n", [Indentation, CurrentLevel, Type]),
+    ok = elvis_utils:info("~s - [~p] ~p", [Indentation, CurrentLevel, Type]),
     _ = lists:map(fun(Child) -> print_node(Child, CurrentLevel + 1) end, Content),
     ok.

From 37da2b782c90d562ca432b4524bf2689912621d0 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Tue, 22 Jul 2025 18:26:05 +0100
Subject: [PATCH 59/67] Initialise the elvis_config_SUITE

---
 test/elvis_SUITE.erl        | 66 +++++++++----------------------------
 test/elvis_config_SUITE.erl | 54 ++++++++++++++++++++++++++++++
 test/elvis_test_utils.erl   | 25 +++++++++++++-
 3 files changed, 94 insertions(+), 51 deletions(-)
 create mode 100644 test/elvis_config_SUITE.erl

diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 204df707..3a192ebd 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -8,8 +8,6 @@
     rock_with_empty_list_config/1,
     rock_with_incomplete_config/1,
     rock_with_list_config/1,
-    rock_with_file_config/1,
-    rock_with_rebar_default_config/1,
     rock_this/1,
     rock_without_colors/1,
     rock_with_parsable/1,
@@ -24,7 +22,6 @@
     rock_with_umbrella_apps/1,
     custom_ruleset/1,
     hrl_ruleset/1,
-    throw_configuration/1,
     find_file_and_check_src/1,
     find_file_with_ignore/1,
     invalid_file/1,
@@ -84,27 +81,6 @@ rock_with_list_config(_Config) ->
     ],
     ok = elvis_core:rock(ElvisConfig).
 
-rock_with_file_config(_Config) ->
-    ConfigPath = "../../config/elvis.config",
-    ElvisConfig = elvis_config:from_file(ConfigPath),
-    Fun = fun() -> elvis_core:rock(ElvisConfig) end,
-    Expected =
-        "# \\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++ "examples/.*\\.erl.*FAIL",
-    [_ | _] = check_some_line_output(Fun, Expected, fun matches_regex/2),
-    ok.
-
-rock_with_rebar_default_config(_Config) ->
-    {ok, _} = file:copy("../../config/rebar.config", "rebar.config"),
-    ElvisConfig = elvis_config:from_rebar("rebar.config"),
-    [#{name := line_length}] =
-        try
-            {fail, Results} = elvis_core:rock(ElvisConfig),
-            [Rule || #{rules := [Rule]} <- Results]
-        after
-            file:delete("rebar.config")
-        end,
-    ok.
-
 rock_this(_Config) ->
     ElvisConfig = elvis_test_utils:config(),
     ok = elvis_core:rock_this(elvis_core, ElvisConfig),
@@ -127,7 +103,11 @@ rock_without_colors(_Config) ->
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected = "\\e.*?m",
     ok =
-        try check_some_line_output(Fun, Expected, fun matches_regex/2) of
+        try
+            elvis_test_utils:check_some_line_output(
+                Fun, Expected, fun elvis_test_utils:matches_regex/2
+            )
+        of
             Result ->
                 ct:fail("Unexpected result ~p", [Result])
         catch
@@ -142,7 +122,11 @@ rock_with_parsable(_Config) ->
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected = ".*\\.erl:\\d:[a-zA-Z0-9_]+:.*",
     ok =
-        try check_some_line_output(Fun, Expected, fun matches_regex/2) of
+        try
+            elvis_test_utils:check_some_line_output(
+                Fun, Expected, fun elvis_test_utils:matches_regex/2
+            )
+        of
             Result ->
                 io:format("~p~n", [Result])
         catch
@@ -175,7 +159,9 @@ rock_with_errors_has_output(_Config) ->
     ElvisConfig = elvis_test_utils:config(),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected = "FAIL",
-    [_ | _] = check_some_line_output(Fun, Expected, fun matches_regex/2),
+    [_ | _] = elvis_test_utils:check_some_line_output(
+        Fun, Expected, fun elvis_test_utils:matches_regex/2
+    ),
     ok.
 
 rock_without_errors_has_no_output(_Config) ->
@@ -201,7 +187,9 @@ rock_without_errors_and_with_verbose_has_output(_Config) ->
     ElvisConfig = elvis_test_utils:config(),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected = "OK",
-    [_ | _] = check_some_line_output(Fun, Expected, fun matches_regex/2),
+    [_ | _] = elvis_test_utils:check_some_line_output(
+        Fun, Expected, fun elvis_test_utils:matches_regex/2
+    ),
     application:unset_env(elvis_core, verbose),
     ok.
 
@@ -352,12 +340,6 @@ hrl_ruleset(_Config) ->
         elvis_core:rock(ElvisConfig),
     ok.
 
-throw_configuration(_Config) ->
-    Filename = "./elvis.config",
-    ok = file:write_file(Filename, <<"-">>),
-    {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(Filename),
-    _ = file:delete(Filename).
-
 find_file_and_check_src(_Config) ->
     Dirs = ["../../test/examples"],
 
@@ -432,24 +414,8 @@ chunk_fold_task(Elem, Multiplier) ->
 %%% Private
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-check_some_line_output(Fun, Expected, FilterFun) ->
-    _ = ct:capture_start(),
-    _ = Fun(),
-    _ = ct:capture_stop(),
-    Lines = ct:capture_get([]),
-    ListFun = fun(Line) -> FilterFun(Line, Expected) end,
-    [_ | _] = lists:filter(ListFun, Lines).
-
 get_output(Fun) ->
     _ = ct:capture_start(),
     _ = Fun(),
     _ = ct:capture_stop(),
     ct:capture_get([]).
-
-matches_regex(Result, Regex) ->
-    case re:run(Result, Regex) of
-        {match, _} ->
-            true;
-        nomatch ->
-            false
-    end.
diff --git a/test/elvis_config_SUITE.erl b/test/elvis_config_SUITE.erl
new file mode 100644
index 00000000..268b7ef2
--- /dev/null
+++ b/test/elvis_config_SUITE.erl
@@ -0,0 +1,54 @@
+-module(elvis_config_SUITE).
+
+-behaviour(ct_suite).
+
+% ct_suite
+-export([all/0, init_per_suite/1, end_per_suite/1]).
+
+% Tests
+-export([rock_with_file_config/1]).
+-export([rock_with_rebar_default_config/1]).
+-export([throw_configuration/1]).
+
+% ct_suite
+all() ->
+    Exports = ?MODULE:module_info(exports),
+    [F || {F, _} <- Exports, not lists:member(F, elvis_test_utils:excluded_funs_all())].
+
+init_per_suite(Config) ->
+    {ok, _} = application:ensure_all_started(elvis_core),
+    Config.
+
+end_per_suite(Config) ->
+    ok = application:stop(elvis_core),
+    Config.
+
+% Tests
+rock_with_file_config(_Config) ->
+    ConfigPath = "../../config/elvis.config",
+    ElvisConfig = elvis_config:from_file(ConfigPath),
+    Fun = fun() -> elvis_core:rock(ElvisConfig) end,
+    Expected =
+        "# \\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++ "examples/.*\\.erl.*FAIL",
+    [_ | _] = elvis_test_utils:check_some_line_output(
+        Fun, Expected, fun elvis_test_utils:matches_regex/2
+    ),
+    ok.
+
+rock_with_rebar_default_config(_Config) ->
+    {ok, _} = file:copy("../../config/rebar.config", "rebar.config"),
+    ElvisConfig = elvis_config:from_rebar("rebar.config"),
+    [#{name := line_length}] =
+        try
+            {fail, Results} = elvis_core:rock(ElvisConfig),
+            [Rule || #{rules := [Rule]} <- Results]
+        after
+            file:delete("rebar.config")
+        end,
+    ok.
+
+throw_configuration(_Config) ->
+    Filename = "./elvis.config",
+    ok = file:write_file(Filename, <<"-">>),
+    {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(Filename),
+    _ = file:delete(Filename).
diff --git a/test/elvis_test_utils.erl b/test/elvis_test_utils.erl
index 794a62fb..a5211674 100644
--- a/test/elvis_test_utils.erl
+++ b/test/elvis_test_utils.erl
@@ -1,6 +1,13 @@
 -module(elvis_test_utils).
 
--export([config/0, config/1, find_file/2, elvis_core_apply_rule/5, excluded_funs_all/0]).
+-export([
+    config/0, config/1,
+    find_file/2,
+    elvis_core_apply_rule/5,
+    excluded_funs_all/0,
+    check_some_line_output/3,
+    matches_regex/2
+]).
 
 excluded_funs_all() ->
     [
@@ -44,3 +51,19 @@ elvis_core_apply_rule(Config, Module, Function, RuleConfig, Filename) ->
         #{items := Items} ->
             Items
     end.
+
+check_some_line_output(Fun, Expected, FilterFun) ->
+    _ = ct:capture_start(),
+    _ = Fun(),
+    _ = ct:capture_stop(),
+    Lines = ct:capture_get([]),
+    ListFun = fun(Line) -> FilterFun(Line, Expected) end,
+    [_ | _] = lists:filter(ListFun, Lines).
+
+matches_regex(Result, Regex) ->
+    case re:run(Result, Regex) of
+        {match, _} ->
+            true;
+        nomatch ->
+            false
+    end.

From e68cd26b1b933bcf89fbdfe9525961007143cbcb Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Tue, 22 Jul 2025 19:06:35 +0100
Subject: [PATCH 60/67] Don't ignore stuff we don't generate any more

---
 .gitignore                              |  1 -
 config/elvis-test-custom-ruleset.config |  2 +-
 config/elvis-test-hrl-files.config      |  2 +-
 config/elvis-test-pa.config             |  2 +-
 config/elvis-test.config                |  4 +-
 config/elvis-umbrella.config            |  8 +--
 config/elvis.config                     | 10 ++--
 config/rebar.config                     |  2 +-
 config/test.config                      | 12 ++---
 config/test.pass.config                 |  2 +-
 rebar.config                            |  2 +-
 test/elvis_SUITE.erl                    | 66 ++++++++++++++-----------
 test/elvis_config_SUITE.erl             |  7 +--
 13 files changed, 63 insertions(+), 57 deletions(-)

diff --git a/.gitignore b/.gitignore
index c3704821..5f4b8e9e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,6 @@ _build/
 doc/
 /rebar3.crashdump
 .rebar3/
-logs
 test/**/*.beam
 test/logs/
 _checkouts/
diff --git a/config/elvis-test-custom-ruleset.config b/config/elvis-test-custom-ruleset.config
index b14c9ba6..b5e084b0 100644
--- a/config/elvis-test-custom-ruleset.config
+++ b/config/elvis-test-custom-ruleset.config
@@ -3,7 +3,7 @@
         {rulesets, #{project => [{elvis_text_style, no_tabs}]}},
         {config, [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/dirs/src"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/dirs/src"],
                 filter => "*.erl",
                 ruleset => project
             }
diff --git a/config/elvis-test-hrl-files.config b/config/elvis-test-hrl-files.config
index bdf89b41..ffacb296 100644
--- a/config/elvis-test-hrl-files.config
+++ b/config/elvis-test-hrl-files.config
@@ -2,7 +2,7 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples/"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples/"],
                 filter => "test_*.hrl",
                 ruleset => hrl_files
             }
diff --git a/config/elvis-test-pa.config b/config/elvis-test-pa.config
index c9e0063d..f2539a2a 100644
--- a/config/elvis-test-pa.config
+++ b/config/elvis-test-pa.config
@@ -2,7 +2,7 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["../../test/examples"],
+                dirs => ["../../../../test/examples"],
                 filter => "user_defined_rules.erl",
                 rules => [{user_defined_rules, rule}]
             }
diff --git a/config/elvis-test.config b/config/elvis-test.config
index 06623e21..339310f4 100644
--- a/config/elvis-test.config
+++ b/config/elvis-test.config
@@ -2,7 +2,7 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["../../src"],
+                dirs => ["../../../../src"],
                 filter => "*.erl",
                 rules =>
                     [
@@ -27,7 +27,7 @@
                 ruleset => erl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/ebin"],
+                dirs => ["../../../../_build/test/lib/elvis_core/ebin"],
                 filter => "*.beam",
                 rules =>
                     [
diff --git a/config/elvis-umbrella.config b/config/elvis-umbrella.config
index 59050ea8..2f411f9a 100644
--- a/config/elvis-umbrella.config
+++ b/config/elvis-umbrella.config
@@ -4,10 +4,10 @@
             #{
                 dirs =>
                     [
-                        "../../_build/test/lib/elvis_core/test/dirs/src",
-                        "../../_build/test/lib/elvis_core/test/dirs/test",
-                        "../../_build/test/lib/elvis_core/test/dirs/apps/**/src",
-                        "../../_build/test/lib/elvis_core/test/dirs/apps/**/test"
+                        "../../../../_build/test/lib/elvis_core/test/dirs/src",
+                        "../../../../_build/test/lib/elvis_core/test/dirs/test",
+                        "../../../../_build/test/lib/elvis_core/test/dirs/apps/**/src",
+                        "../../../../_build/test/lib/elvis_core/test/dirs/apps/**/test"
                     ],
                 filter => "*.erl",
                 ruleset => erl_files
diff --git a/config/elvis.config b/config/elvis.config
index 693b2c52..1d0d5da4 100644
--- a/config/elvis.config
+++ b/config/elvis.config
@@ -2,27 +2,27 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.erl",
                 ruleset => erl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.hrl",
                 ruleset => hrl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/non_compilable_examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/non_compilable_examples"],
                 filter => "*.erl",
                 ruleset => erl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.beam",
                 ruleset => beam_files
             },
             #{
-                dirs => ["../.."],
+                dirs => ["../../../.."],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
diff --git a/config/rebar.config b/config/rebar.config
index d8755dfe..e503ccd7 100644
--- a/config/rebar.config
+++ b/config/rebar.config
@@ -8,7 +8,7 @@
 {elvis, [
     {config, [
         #{
-            dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+            dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
             filter => "*.erl",
             rules => [{elvis_text_style, line_length, #{limit => 135}}]
         }
diff --git a/config/test.config b/config/test.config
index 155962b8..3fc32768 100644
--- a/config/test.config
+++ b/config/test.config
@@ -2,7 +2,7 @@
     {elvis_core, [
         {config, [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.erl",
                 rules =>
                     [
@@ -15,13 +15,13 @@
                 ruleset => erl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.hrl",
                 rules => [],
                 ruleset => hrl_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.beam",
                 rules =>
                     [
@@ -33,15 +33,15 @@
                 ruleset => beam_files
             },
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "rebar3.config.success",
                 ruleset => rebar_config
             },
             #{
                 dirs =>
                     [
-                        "../../_build/test/lib/elvis_core/test/dirs/apps/app1",
-                        "../../_build/test/lib/elvis_core/test/dirs/apps/app2"
+                        "../../../../_build/test/lib/elvis_core/test/dirs/apps/app1",
+                        "../../../../_build/test/lib/elvis_core/test/dirs/apps/app2"
                     ],
                 filter => ".gitignore",
                 ruleset => gitignore
diff --git a/config/test.pass.config b/config/test.pass.config
index 41449693..1a428119 100644
--- a/config/test.pass.config
+++ b/config/test.pass.config
@@ -3,7 +3,7 @@
     {elvis, [
         {config, [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "*.erl",
                 rules => [{elvis_text_style, line_length, #{limit => 800}}]
             }
diff --git a/rebar.config b/rebar.config
index 08cb04ee..c2bfdafd 100644
--- a/rebar.config
+++ b/rebar.config
@@ -16,7 +16,7 @@
         {deps, [{meck, "0.9.2"}]},
         {erl_opts, [nowarn_missing_spec, nowarn_export_all]},
         {dialyzer, [{warnings, [no_return, error_handling]}, {plt_extra_apps, [common_test]}]},
-        {ct_opts, [{sys_config, ["./config/test.config"]}, {logdir, "./logs"}, {verbose, true}]},
+        {ct_opts, [{sys_config, ["./config/test.config"]}, {verbose, true}]},
         {cover_enabled, true},
         {cover_opts, [verbose]}
     ]}
diff --git a/test/elvis_SUITE.erl b/test/elvis_SUITE.erl
index 3a192ebd..377c13a1 100644
--- a/test/elvis_SUITE.erl
+++ b/test/elvis_SUITE.erl
@@ -74,7 +74,7 @@ rock_with_incomplete_config(_Config) ->
 rock_with_list_config(_Config) ->
     ElvisConfig = [
         #{
-            dirs => ["../../test/dirs/src"],
+            dirs => ["../../../../test/dirs/src"],
             rules => [{elvis_text_style, line_length, disable}],
             filter => "*.erl"
         }
@@ -93,7 +93,7 @@ rock_this(_Config) ->
                 ok
         end,
 
-    Path = "../../_build/test/lib/elvis_core/test/examples/fail_line_length.erl",
+    Path = "../../../../_build/test/lib/elvis_core/test/examples/fail_line_length.erl",
     {fail, _} = elvis_core:rock_this(Path, ElvisConfig),
 
     ok.
@@ -139,7 +139,7 @@ rock_with_parsable(_Config) ->
 rock_with_non_parsable_file(_Config) ->
     ElvisConfig = elvis_test_utils:config(),
     Path =
-        "../../_build/test/lib/elvis_core/test/non_compilable_examples/fail_non_parsable_file.erl",
+        "../../../../_build/test/lib/elvis_core/test/non_compilable_examples/fail_non_parsable_file.erl",
     try
         elvis_core:rock_this(Path, ElvisConfig)
     catch
@@ -165,7 +165,7 @@ rock_with_errors_has_output(_Config) ->
     ok.
 
 rock_without_errors_has_no_output(_Config) ->
-    ConfigPath = "../../config/test.pass.config",
+    ConfigPath = "../../../../config/test.pass.config",
     ElvisConfig = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Output = get_output(Fun),
@@ -199,17 +199,17 @@ rock_with_rule_groups(_Config) ->
     RulesGroupConfig =
         [
             #{
-                dirs => ["../../test/dirs/apps/app3/src"],
+                dirs => ["../../../../test/dirs/apps/app3/src"],
                 filter => "*.erl",
                 ruleset => erl_files
             },
             #{
-                dirs => ["../../test/dirs/apps/app3/include"],
+                dirs => ["../../../../test/dirs/apps/app3/include"],
                 filter => "*.hrl",
                 ruleset => hrl_files
             },
             #{
-                dirs => ["../../test/dirs/apps/app3"],
+                dirs => ["../../../../test/dirs/apps/app3"],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
@@ -232,7 +232,7 @@ rock_with_rule_groups(_Config) ->
     OverrideConfig =
         [
             #{
-                dirs => ["../../test/dirs/apps/app3/src"],
+                dirs => ["../../../../test/dirs/apps/app3/src"],
                 filter => "*.erl",
                 ruleset => erl_files,
                 rules =>
@@ -244,7 +244,7 @@ rock_with_rule_groups(_Config) ->
                     ]
             },
             #{
-                dirs => ["../../test/dirs/apps/app3"],
+                dirs => ["../../../../test/dirs/apps/app3"],
                 filter => "rebar.config",
                 ruleset => rebar_config
             }
@@ -253,11 +253,11 @@ rock_with_rule_groups(_Config) ->
 
 rock_this_skipping_files(_Config) ->
     meck:new(elvis_file, [passthrough]),
-    Dirs = ["../../_build/test/lib/elvis_core/test/examples"],
+    Dirs = ["../../../../_build/test/lib/elvis_core/test/examples"],
     [File] = elvis_file:find_files(Dirs, "small.erl"),
     Path = elvis_file:path(File),
-    ConfigPath = "../../config/elvis-test-pa.config",
-    {ok, user_defined_rules} = compile:file("../../test/examples/user_defined_rules.erl"),
+    ConfigPath = "../../../../config/elvis-test-pa.config",
+    {ok, user_defined_rules} = compile:file("../../../../test/examples/user_defined_rules.erl"),
     {module, user_defined_rules} = code:ensure_loaded(user_defined_rules),
     ElvisConfig = elvis_config:from_file(ConfigPath),
     ok = elvis_core:rock_this(Path, ElvisConfig),
@@ -267,7 +267,7 @@ rock_this_skipping_files(_Config) ->
 
 rock_this_not_skipping_files(_Config) ->
     meck:new(elvis_file, [passthrough]),
-    Dirs = ["../../_build/test/lib/elvis_core/test/examples"],
+    Dirs = ["../../../../_build/test/lib/elvis_core/test/examples"],
     [File] = elvis_file:find_files(Dirs, "small.erl"),
     Path = elvis_file:path(File),
     ElvisConfig = elvis_test_utils:config(),
@@ -277,34 +277,37 @@ rock_this_not_skipping_files(_Config) ->
     ok.
 
 rock_with_umbrella_apps(_Config) ->
-    ElvisUmbrellaConfigFile = "../../config/elvis-umbrella.config",
+    ElvisUmbrellaConfigFile = "../../../../config/elvis-umbrella.config",
     ElvisConfig = elvis_config:from_file(ElvisUmbrellaConfigFile),
     {fail, [
-        #{file := "../../_build/test/lib/elvis_core/test/dirs/test/dir_test.erl"},
-        #{file := "../../_build/test/lib/elvis_core/test/dirs/src/dirs_src.erl"},
-        #{file := "../../_build/test/lib/elvis_core/test/dirs/apps/app3/src/app3_example.erl"},
+        #{file := "../../../../_build/test/lib/elvis_core/test/dirs/test/dir_test.erl"},
+        #{file := "../../../../_build/test/lib/elvis_core/test/dirs/src/dirs_src.erl"},
         #{
             file :=
-                "../../_build/test/lib/elvis_core/test/dirs/apps/app2/test/dirs_apps_app2_test.erl"
+                "../../../../_build/test/lib/elvis_core/test/dirs/apps/app3/src/app3_example.erl"
         },
         #{
             file :=
-                "../../_build/test/lib/elvis_core/test/dirs/apps/app2/src/dirs_apps_app2_src.erl"
+                "../../../../_build/test/lib/elvis_core/test/dirs/apps/app2/test/dirs_apps_app2_test.erl"
         },
         #{
             file :=
-                "../../_build/test/lib/elvis_core/test/dirs/apps/app1/test/dirs_apps_app1_test.erl"
+                "../../../../_build/test/lib/elvis_core/test/dirs/apps/app2/src/dirs_apps_app2_src.erl"
         },
         #{
             file :=
-                "../../_build/test/lib/elvis_core/test/dirs/apps/app1/src/dirs_apps_app1_src.erl"
+                "../../../../_build/test/lib/elvis_core/test/dirs/apps/app1/test/dirs_apps_app1_test.erl"
+        },
+        #{
+            file :=
+                "../../../../_build/test/lib/elvis_core/test/dirs/apps/app1/src/dirs_apps_app1_src.erl"
         }
     ]} =
         elvis_core:rock(ElvisConfig),
     ok.
 
 rock_with_invalid_rules(_Config) ->
-    ConfigPath = "../../test/examples/invalid_rules.elvis.config",
+    ConfigPath = "../../../../test/examples/invalid_rules.elvis.config",
     {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(ConfigPath),
     ok.
 
@@ -312,7 +315,7 @@ rock_with_invalid_rules(_Config) ->
 %%% Utils
 
 custom_ruleset(_Config) ->
-    ConfigPath = "../../config/elvis-test-custom-ruleset.config",
+    ConfigPath = "../../../../config/elvis-test-custom-ruleset.config",
     ElvisConfig = elvis_config:from_file(ConfigPath),
     NoTabs = elvis_rule:new(elvis_text_style, no_tabs),
     [[NoTabs]] = elvis_config:rules(ElvisConfig),
@@ -322,18 +325,21 @@ custom_ruleset(_Config) ->
 
     %% read unknown ruleset configuration to ensure rulesets from
     %% previous load do not stick around
-    ConfigPathMissing = "../../config/elvis-test-unknown-ruleset.config",
+    ConfigPathMissing = "../../../../config/elvis-test-unknown-ruleset.config",
     ElvisConfigMissing = elvis_config:from_file(ConfigPathMissing),
     [[]] = elvis_config:rules(ElvisConfigMissing),
     ok.
 
 hrl_ruleset(_Config) ->
-    ConfigPath = "../../config/elvis-test-hrl-files.config",
+    ConfigPath = "../../../../config/elvis-test-hrl-files.config",
     ElvisConfig = elvis_config:from_file(ConfigPath),
     {fail, [
-        #{file := "../../_build/test/lib/elvis_core/test/examples/test_good.hrl", rules := []},
         #{
-            file := "../../_build/test/lib/elvis_core/test/examples/test_bad.hrl",
+            file := "../../../../_build/test/lib/elvis_core/test/examples/test_good.hrl",
+            rules := []
+        },
+        #{
+            file := "../../../../_build/test/lib/elvis_core/test/examples/test_bad.hrl",
             rules := [#{name := line_length}]
         }
     ]} =
@@ -341,7 +347,7 @@ hrl_ruleset(_Config) ->
     ok.
 
 find_file_and_check_src(_Config) ->
-    Dirs = ["../../test/examples"],
+    Dirs = ["../../../../test/examples"],
 
     [] = elvis_file:find_files(Dirs, "doesnt_exist.erl"),
     [File] = elvis_file:find_files(Dirs, "small.erl"),
@@ -357,12 +363,12 @@ find_file_and_check_src(_Config) ->
     {error, enoent} = elvis_file:src(#{path => "doesnt_exist.erl"}).
 
 find_file_with_ignore(_Config) ->
-    Dirs = ["../../test/examples"],
+    Dirs = ["../../../../test/examples"],
     Filter = "find_test*.erl",
     Ignore = elvis_config:ignore(#{ignore => [find_test1]}),
     Files = [_, _] = elvis_file:find_files(Dirs, Filter),
     [_, _] = elvis_file:filter_files(Files, Dirs, Filter, []),
-    [#{path := "../../test/examples/find_test2.erl"}] =
+    [#{path := "../../../../test/examples/find_test2.erl"}] =
         elvis_file:filter_files(Files, Dirs, Filter, Ignore).
 
 invalid_file(_Config) ->
diff --git a/test/elvis_config_SUITE.erl b/test/elvis_config_SUITE.erl
index 268b7ef2..df5ba507 100644
--- a/test/elvis_config_SUITE.erl
+++ b/test/elvis_config_SUITE.erl
@@ -25,18 +25,19 @@ end_per_suite(Config) ->
 
 % Tests
 rock_with_file_config(_Config) ->
-    ConfigPath = "../../config/elvis.config",
+    ConfigPath = "../../../../config/elvis.config",
     ElvisConfig = elvis_config:from_file(ConfigPath),
     Fun = fun() -> elvis_core:rock(ElvisConfig) end,
     Expected =
-        "# \\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++ "examples/.*\\.erl.*FAIL",
+        "# \\.\\./\\.\\./\\.\\./\\.\\./_build/test/lib/elvis_core/test/" ++
+            "examples/.*\\.erl.*FAIL",
     [_ | _] = elvis_test_utils:check_some_line_output(
         Fun, Expected, fun elvis_test_utils:matches_regex/2
     ),
     ok.
 
 rock_with_rebar_default_config(_Config) ->
-    {ok, _} = file:copy("../../config/rebar.config", "rebar.config"),
+    {ok, _} = file:copy("../../../../config/rebar.config", "rebar.config"),
     ElvisConfig = elvis_config:from_rebar("rebar.config"),
     [#{name := line_length}] =
         try

From c41293d1db33df6a020d0dbaac074790f1ca5609 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 24 Jul 2025 18:35:42 +0100
Subject: [PATCH 61/67] Further minor tweaks on output

---
 src/elvis_utils.erl | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/elvis_utils.erl b/src/elvis_utils.erl
index ebaf7105..350ba137 100644
--- a/src/elvis_utils.erl
+++ b/src/elvis_utils.erl
@@ -36,13 +36,15 @@ list_to_str([], Acc) ->
     "[" ++ string:join(Acc, ", ") ++ "]";
 list_to_str([H0 | T], Acc) ->
     H =
-        case is_list(H0) of
-            true ->
+        case H0 of
+            H0 when is_list(H0) ->
                 "\"" ++ H0 ++ "\"";
+            H0 when is_binary(H0) ->
+                "<<\"" ++ to_str(H0) ++ "\">>";
             _ ->
-                H0
+                to_str(H0)
         end,
-    list_to_str(T, [to_str(H) | Acc]).
+    list_to_str(T, [H | Acc]).
 
 -spec split_all_lines(binary()) -> [binary(), ...].
 split_all_lines(Binary) ->

From 9710c29b20c435f70362015d7d33521316f8741e Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 24 Jul 2025 18:39:04 +0100
Subject: [PATCH 62/67] Fix for test results

---
 src/elvis_config.erl | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 32fe8724..95f495d3 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -155,8 +155,8 @@ fetch_elvis_config_from(AppConfig) ->
         Elvis ->
             from_static(config, {elvis, Elvis})
     catch
-        {invalid_config, _} = Caught ->
-            {fail, [{throw, Caught}]}
+        {invalid_config, Message} ->
+            {fail, [{throw, {invalid_config, lists:flatten(Message)}}]}
     end.
 
 default_for(app) ->
@@ -548,9 +548,9 @@ no_default_ruleset_override(What, CustomRulesets) ->
     end.
 
 is_valid_config(What, CustomRulesetNames, Configset0) ->
-    Configset = wrap_in_list(Configset0),
     maybe
-        ok ?= is_nonempty_list(What, Configset),
+        ok ?= is_nonempty_list(What, Configset0),
+        Configset = wrap_in_list(Configset0),
         ok ?= all_configs_are_valid(What, CustomRulesetNames, Configset)
     else
         {error, FormatData} ->
@@ -615,6 +615,8 @@ config_is_valid(CustomRulesetNames, Config) ->
             {error, ValidError}
     end.
 
+map_keys_are_in(Map, _Keys) when not is_map(Map) ->
+    {error, "element is expected to be a map."};
 map_keys_are_in(Map, Keys) ->
     Filtered = [Key || Key <- maps:keys(Map), not lists:member(Key, Keys)],
     case Filtered of

From 63d135588d03a625b32a9586bc3f150c43b93cc6 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 24 Jul 2025 18:51:51 +0100
Subject: [PATCH 63/67] Fix for test results

---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 95f495d3..285fcf8f 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -741,7 +741,7 @@ either_rules_is_nonempty_or_ruleset_is_defined([_ | _] = _Rules, _Ruleset) ->
 either_rules_is_nonempty_or_ruleset_is_defined(_Rules, Ruleset) when Ruleset =/= undefined ->
     ok;
 either_rules_is_nonempty_or_ruleset_is_defined(_Rules, _Ruleset) ->
-    io_lib:format("either rules or ruleset is expected to be defined.", []).
+    {error, io_lib:format("either rules or ruleset is expected to be defined.", [])}.
 
 check_rule_for_options(Rule, AccInI) ->
     case elvis_rule:defkeys(Rule) of

From 558855100e7af8d89b107f01dbb5275ebc3b3f50 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Tue, 29 Jul 2025 09:12:59 +0100
Subject: [PATCH 64/67] Act on review comment

---
 test/elvis_test_utils.erl | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/test/elvis_test_utils.erl b/test/elvis_test_utils.erl
index a5211674..d66c6355 100644
--- a/test/elvis_test_utils.erl
+++ b/test/elvis_test_utils.erl
@@ -61,9 +61,4 @@ check_some_line_output(Fun, Expected, FilterFun) ->
     [_ | _] = lists:filter(ListFun, Lines).
 
 matches_regex(Result, Regex) ->
-    case re:run(Result, Regex) of
-        {match, _} ->
-            true;
-        nomatch ->
-            false
-    end.
+    nomatch =/= re:run(Result, Regex).

From 6e862cc065b3053860e2eed27c12d49897f3a350 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 30 Jul 2025 15:45:42 +0100
Subject: [PATCH 65/67] Fix it

---
 test/style_SUITE.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/style_SUITE.erl b/test/style_SUITE.erl
index 62cbe9c0..bf14548e 100644
--- a/test/style_SUITE.erl
+++ b/test/style_SUITE.erl
@@ -2864,7 +2864,7 @@ oddities(_Config) ->
     ElvisConfig =
         [
             #{
-                dirs => ["../../_build/test/lib/elvis_core/test/examples"],
+                dirs => ["../../../../_build/test/lib/elvis_core/test/examples"],
                 filter => "odditiesß.erl",
                 ruleset => erl_files,
                 rules => [{elvis_style, no_god_modules, #{limit => 0}}]

From 2bf6711fe97141e17ed079ef2fc46b0ad0ddebf3 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 30 Jul 2025 16:57:20 +0100
Subject: [PATCH 66/67] Minor tweak for test results

I can't simply validate rules as being non-empty
because it is, by default, so what I state is
"you either provide a non-empty list or a valid ruleset"
---
 src/elvis_config.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 285fcf8f..0e29d1aa 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -741,7 +741,7 @@ either_rules_is_nonempty_or_ruleset_is_defined([_ | _] = _Rules, _Ruleset) ->
 either_rules_is_nonempty_or_ruleset_is_defined(_Rules, Ruleset) when Ruleset =/= undefined ->
     ok;
 either_rules_is_nonempty_or_ruleset_is_defined(_Rules, _Ruleset) ->
-    {error, io_lib:format("either rules or ruleset is expected to be defined.", [])}.
+    {error, io_lib:format("either 'rules' is a non-empty list or 'ruleset' is defined.", [])}.
 
 check_rule_for_options(Rule, AccInI) ->
     case elvis_rule:defkeys(Rule) of

From 1fa87910883c75b25aebb2533408648d7e612555 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Wed, 30 Jul 2025 16:57:42 +0100
Subject: [PATCH 67/67] Throw earlier when elvis.config exists but is invalid
 Erlang

---
 src/elvis_config.erl        | 9 +++++++++
 test/elvis_config_SUITE.erl | 9 ++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/elvis_config.erl b/src/elvis_config.erl
index 0e29d1aa..c909846b 100644
--- a/src/elvis_config.erl
+++ b/src/elvis_config.erl
@@ -125,6 +125,15 @@ consult_elvis_config(File) ->
         {ok, [AppConfig]} when is_list(AppConfig) ->
             elvis_utils:debug("elvis.config consultable; using it", []),
             AppConfig;
+        {error, {Line, Mod, Term}} ->
+            % In this very specific case we prefer to throw, since we make efforts
+            % to provide a valid config., but we also need to make sure the file
+            % is readable
+            exit(
+                lists:flatten(
+                    io_lib:format("elvis.config unconsultable: ~p, ~p, ~p", [Line, Mod, Term])
+                )
+            );
         _ ->
             elvis_utils:debug("elvis.config unconsultable", []),
             default_for(app)
diff --git a/test/elvis_config_SUITE.erl b/test/elvis_config_SUITE.erl
index df5ba507..e6f6a492 100644
--- a/test/elvis_config_SUITE.erl
+++ b/test/elvis_config_SUITE.erl
@@ -51,5 +51,12 @@ rock_with_rebar_default_config(_Config) ->
 throw_configuration(_Config) ->
     Filename = "./elvis.config",
     ok = file:write_file(Filename, <<"-">>),
-    {fail, [{throw, {invalid_config, _}}]} = elvis_config:from_file(Filename),
+    ok =
+        try
+            elvis_config:from_file(Filename),
+            fail
+        catch
+            exit:"elvis.config unconsultable: 1, erl_parse, [\"syntax error before: \",[]]" ->
+                ok
+        end,
     _ = file:delete(Filename).