feat: Support Elixir 1.18

.envrc

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+direnv_load mise direnv exec

.github/workflows/build.yml

@@ -10,31 +10,6 @@ permissions:
   contents: read
 
 jobs:
-  build-otp-23:
-    name: Build and test on OTP 23
-    runs-on: ubuntu-20.04
-    strategy:
-      matrix:
-        elixir_version:
-          - "1.10"
-          - "1.11"
-          - "1.12"
-          - "1.13"
-    steps:
-      - uses: actions/checkout@v3
-      - uses: erlef/setup-beam@v1
-        with:
-          elixir-version: ${{ matrix.elixir_version }}
-          otp-version: "23"
-      - uses: actions/cache@v3
-        with:
-          path: deps
-          key: 23-${{ matrix.elixir_version }}-${{ hashFiles('**/mix.lock') }}
-          restore-keys: |
-            23-${{ matrix.elixir_version }}-
-            23-
-      - run: mix deps.get
-      - run: mix test
   build-otp-24:
     name: Build and test on OTP 24
     runs-on: ubuntu-20.04
@@ -92,6 +67,7 @@ jobs:
         elixir_version:
           - "1.14"
           - "1.15"
+          - "1.16"
     steps:
       - uses: actions/checkout@v3
       - uses: erlef/setup-beam@v1
@@ -107,3 +83,26 @@ jobs:
             26-
       - run: mix deps.get
       - run: mix test
+  build-otp-27:
+    name: Build and test on OTP 27
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        elixir_version:
+          - "1.17"
+          - "1.18"
+    steps:
+      - uses: actions/checkout@v3
+      - uses: erlef/setup-beam@v1
+        with:
+          elixir-version: ${{ matrix.elixir_version }}
+          otp-version: "27"
+      - uses: actions/cache@v3
+        with:
+          path: deps
+          key: 27-${{ matrix.elixir_version }}-${{ hashFiles('**/mix.lock') }}
+          restore-keys: |
+            27-${{ matrix.elixir_version }}-
+            27-
+      - run: mix deps.get
+      - run: mix test

.github/workflows/publish.yml

@@ -16,8 +16,8 @@ jobs:
       - uses: actions/checkout@v3
       - uses: erlef/setup-beam@v1
         with:
-          elixir-version: "1.14"
-          otp-version: "24"
+          elixir-version: "1.18"
+          otp-version: "27"
       - run: mix deps.get
       - run: mix test
       - run: mix hex.publish --yes

lib/assert_match.ex

@@ -6,11 +6,19 @@ defmodule AssertMatch do
   @doc """
   Pipe-friendly equality/matching assertion.
 
-  Performs:
+  Performs `assert/1` with:
 
   - `=~` for Regex patterns
+  - `match?/2` for patterns with guards
   - `=` for other patterns
 
+  For the third variant, it can utilize bindings inside the pattern from outside!
+
+      %{key: 1}
+      |> assert_match(%{key: value})
+
+      assert value == 1
+
   ## Extraction of pinned function calls
 
   Elixir's `^/1` (pin operator) usually does not allow runtime function calls,
@@ -33,7 +41,27 @@ defmodule AssertMatch do
       })
 
   You cannot nest pinned expressions. See test/assert_match_test.exs for more usages.
+
+  ## Guards
+
+  Guards are supported, but with limitations: if guards are used, bindings inside patterns cannot be used from outside.
+
+      %{key: 1}
+      |> assert_match(map when is_map(map))
+      # => Passes
+
+      assert map == %{key: 1}
+      # => error: undefined variable "map"
+
+  Related: bindings inside patterns that are NOT used in the guards are warned as unused.
+
+      %{key: 1}
+      |> assert_match(%{key: value} = map when not is_map_key(map, :nonkey))
+      # => warning: variable "value" is unused (if the variable is not meant to be used, prefix it with an underscore)
+
+  This is a relatively new limitation introduced in Elixir 1.18, as a side-effect of [this change](https://github.com/elixir-lang/elixir/pull/13817).
   """
+  @spec assert_match(any, Macro.t()) :: any
   defmacro assert_match(subject, pattern) do
     case pattern do
       falsy when falsy == nil or falsy == false ->
@@ -55,11 +83,23 @@ defmodule AssertMatch do
         {matchable_ast, extracted_tmpvars} = extract_pinned_function_calls_to_variables(pattern)
         # Notice pattern is at left-hand side
         # In Elixir 1.10+, match assertions can display rich diffs for various subject-pattern combinations
-        quote do
-          right = unquote(subject)
-          unquote(tmpvar_definitions(extracted_tmpvars))
-          ExUnit.Assertions.assert(unquote(matchable_ast) = right)
-          right
+        case matchable_ast do
+          {:when, _location, _branches} = ast_with_guard ->
+            # After Elixir 1.18, patterns with guards require special treatment. cf. https://github.com/elixir-lang/elixir/pull/13817
+            quote do
+              right = unquote(subject)
+              unquote(tmpvar_definitions(extracted_tmpvars))
+              ExUnit.Assertions.assert(match?(unquote(ast_with_guard), right))
+              right
+            end
+
+          _otherwise ->
+            quote do
+              right = unquote(subject)
+              unquote(tmpvar_definitions(extracted_tmpvars))
+              ExUnit.Assertions.assert(unquote(matchable_ast) = right)
+              right
+            end
         end
     end
   end

mise.toml

@@ -0,0 +1,3 @@
+[tools]
+elixir = "1.18.2-otp-27"
+erlang = "27.2.1"

mix.exs

@@ -6,7 +6,7 @@ defmodule AssertMatch.MixProject do
       app: :assert_match,
       description:
         "Leverages pattern matching & pipeline in Elixir tests by pipe-friendly `assert_match/2`",
-      version: "1.0.0",
+      version: "1.1.0",
       elixir: "~> 1.10",
       package: package(),
       deps: [{:ex_doc, "~> 0.27", only: :dev, runtime: false}]

test/assert_match_test.exs

@@ -18,7 +18,7 @@ defmodule AssertMatchTest do
     end
 
     test "should work with regex" do
-      assert_match("prefix match", ~R/prefix/)
+      assert_match("prefix match", ~r/prefix/)
       assert_match("prefix match", ~r/#{"prefix"}/)
     end
 
@@ -30,6 +30,13 @@ defmodule AssertMatchTest do
       assert_match([1, 2], [_ | _])
     end
 
+    test "should work with guards" do
+      assert_match(%{key: 1}, map when is_map_key(map, :key))
+
+      # guard works with assert_match/2 but has limitation: bindings inside patterns cannot be used from outside
+      assert_match(%{key: 1}, %{key: _value} = map when not is_map_key(map, :nonkey))
+    end
+
     test "should work with incomplete struct patterns" do
       # As a value, %Date{year: 2018} raises since [:month, :day] are also enforced.
       assert_match(~D[2018-01-01], %Date{year: 2018})