[clang-tidy] Fix broken HeaderFilterRegex when read from config file #133582

carlosgalvezp · 2025-03-29T12:47:14Z

PR #91400 broke the usage of HeaderFilterRegex via config file, because it is now created at a different point in the execution and leads to a different value.

The result of that is that using HeaderFilterRegex only in the config file does NOT work, in other words clang-tidy stops triggering warnings on header files, thereby losing a lot of coverage.

This patch reverts the logic so that the header filter is created upon calling the getHeaderFilter() function.

Additionally, this patch adds 2 unit tests to prevent regressions in the future:

One of them, "simple", tests the most basic use case with a single top-level .clang-tidy file.
The second one, "inheritance", demonstrates that the subfolder only gets warnings from headers within it, and not from parent headers.

Fixes #118009
Fixes #121969
Fixes #133453

llvmbot · 2025-03-29T12:47:50Z

@llvm/pr-subscribers-clang-tidy

Author: Carlos Galvez (carlosgalvezp)

Changes

PR #91400 broke the usage of HeaderFilterRegex via config file, because it is now created at a different point in the execution and leads to a different value.

The result of that is that using HeaderFilterRegex only in the config file does NOT work, in other words clang-tidy stops triggering warnings on header files, thereby losing a lot of coverage.

This patch reverts the logic so that the header filter is created upon calling the getHeaderFilter() function.

Additionally, this patch adds 2 unit tests to prevent regressions in the future:

One of them, "simple", tests the most basic use case with a single top-level .clang-tidy file.
The second one, "inheritance", demonstrates that the subfolder only gets warnings from headers within it, and not from parent headers.

Fixes #118009, #121969, #133453

Full diff: https://github.com/llvm/llvm-project/pull/133582.diff

12 Files Affected:

(modified) clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp (+19-17)
(modified) clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h (+4)
(modified) clang-tools-extra/docs/ReleaseNotes.rst (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy (+2)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp (+6)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h (+1)

diff --git a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
index 4c75b42270114..71e852545203e 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
@@ -311,18 +311,7 @@ ClangTidyDiagnosticConsumer::ClangTidyDiagnosticConsumer(
     : Context(Ctx), ExternalDiagEngine(ExternalDiagEngine),
       RemoveIncompatibleErrors(RemoveIncompatibleErrors),
       GetFixesFromNotes(GetFixesFromNotes),
-      EnableNolintBlocks(EnableNolintBlocks) {
-
-  if (Context.getOptions().HeaderFilterRegex &&
-      !Context.getOptions().HeaderFilterRegex->empty())
-    HeaderFilter =
-        std::make_unique<llvm::Regex>(*Context.getOptions().HeaderFilterRegex);
-
-  if (Context.getOptions().ExcludeHeaderFilterRegex &&
-      !Context.getOptions().ExcludeHeaderFilterRegex->empty())
-    ExcludeHeaderFilter = std::make_unique<llvm::Regex>(
-        *Context.getOptions().ExcludeHeaderFilterRegex);
-}
+      EnableNolintBlocks(EnableNolintBlocks) {}
 
 void ClangTidyDiagnosticConsumer::finalizeLastError() {
   if (!Errors.empty()) {
@@ -571,17 +560,30 @@ void ClangTidyDiagnosticConsumer::checkFilters(SourceLocation Location,
   }
 
   StringRef FileName(File->getName());
-  LastErrorRelatesToUserCode =
-      LastErrorRelatesToUserCode || Sources.isInMainFile(Location) ||
-      (HeaderFilter &&
-       (HeaderFilter->match(FileName) &&
-        !(ExcludeHeaderFilter && ExcludeHeaderFilter->match(FileName))));
+  LastErrorRelatesToUserCode = LastErrorRelatesToUserCode ||
+                               Sources.isInMainFile(Location) ||
+                               (getHeaderFilter()->match(FileName) &&
+                                !getExcludeHeaderFilter()->match(FileName));
 
   unsigned LineNumber = Sources.getExpansionLineNumber(Location);
   LastErrorPassesLineFilter =
       LastErrorPassesLineFilter || passesLineFilter(FileName, LineNumber);
 }
 
+llvm::Regex *ClangTidyDiagnosticConsumer::getHeaderFilter() {
+  if (!HeaderFilter)
+    HeaderFilter =
+        std::make_unique<llvm::Regex>(*Context.getOptions().HeaderFilterRegex);
+  return HeaderFilter.get();
+}
+
+llvm::Regex *ClangTidyDiagnosticConsumer::getExcludeHeaderFilter() {
+  if (!ExcludeHeaderFilter)
+    ExcludeHeaderFilter = std::make_unique<llvm::Regex>(
+        *Context.getOptions().ExcludeHeaderFilterRegex);
+  return ExcludeHeaderFilter.get();
+}
+
 void ClangTidyDiagnosticConsumer::removeIncompatibleErrors() {
   // Each error is modelled as the set of intervals in which it applies
   // replacements. To detect overlapping replacements, we use a sweep line
diff --git a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
index ff42f96a0477b..d6cf6a2b2731e 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
+++ b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
@@ -302,6 +302,10 @@ class ClangTidyDiagnosticConsumer : public DiagnosticConsumer {
   /// context.
   llvm::Regex *getHeaderFilter();
 
+  /// Returns the \c ExcludeHeaderFilter constructed for the options set in the
+  /// context.
+  llvm::Regex *getExcludeHeaderFilter();
+
   /// Updates \c LastErrorRelatesToUserCode and LastErrorPassesLineFilter
   /// according to the diagnostic \p Location.
   void checkFilters(SourceLocation Location, const SourceManager &Sources);
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6cb8d572d3a78..6c1f05009df98 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -94,6 +94,9 @@ Improvements to clang-tidy
 - Improved :program:`clang-tidy-diff.py` script. Add the `-warnings-as-errors`
   argument to treat warnings as errors.
 
+- Fixed bug in :program:`clang-tidy` by which `HeaderFilterRegex` did not take
+  effect when passed via the `.clang-tidy` file.
+
 New checks
 ^^^^^^^^^^
 
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy
new file mode 100644
index 0000000000000..f4210353f94de
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy
@@ -0,0 +1 @@
+HeaderFilterRegex: '.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp
new file mode 100644
index 0000000000000..79622418d6dff
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp
@@ -0,0 +1,3 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK: foo.h:1:12: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h
new file mode 100644
index 0000000000000..f61d4c2923b50
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h
@@ -0,0 +1 @@
+struct X { X(int); };
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy
new file mode 100644
index 0000000000000..96706c1428047
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy
@@ -0,0 +1,2 @@
+InheritParentConfig: true
+HeaderFilterRegex: 'subfolder/.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp
new file mode 100644
index 0000000000000..7576b1af74bfa
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp
@@ -0,0 +1,6 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- -I $(dirname %S) 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK-NOT: foo.h:1:12: warning: single-argument constructors must be marked explicit
+
+#include "bar.h"
+// CHECK: bar.h:1:13: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h
new file mode 100644
index 0000000000000..ee12d00d334dd
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h
@@ -0,0 +1 @@
+struct XX { XX(int); };
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy
new file mode 100644
index 0000000000000..f4210353f94de
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy
@@ -0,0 +1 @@
+HeaderFilterRegex: '.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp
new file mode 100644
index 0000000000000..79622418d6dff
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp
@@ -0,0 +1,3 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK: foo.h:1:12: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h
new file mode 100644
index 0000000000000..f61d4c2923b50
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h
@@ -0,0 +1 @@
+struct X { X(int); };

llvmbot · 2025-03-29T12:47:50Z

@llvm/pr-subscribers-clang-tools-extra

Author: Carlos Galvez (carlosgalvezp)

Changes

PR #91400 broke the usage of HeaderFilterRegex via config file, because it is now created at a different point in the execution and leads to a different value.

The result of that is that using HeaderFilterRegex only in the config file does NOT work, in other words clang-tidy stops triggering warnings on header files, thereby losing a lot of coverage.

This patch reverts the logic so that the header filter is created upon calling the getHeaderFilter() function.

Additionally, this patch adds 2 unit tests to prevent regressions in the future:

One of them, "simple", tests the most basic use case with a single top-level .clang-tidy file.
The second one, "inheritance", demonstrates that the subfolder only gets warnings from headers within it, and not from parent headers.

Fixes #118009, #121969, #133453

Full diff: https://github.com/llvm/llvm-project/pull/133582.diff

12 Files Affected:

(modified) clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp (+19-17)
(modified) clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h (+4)
(modified) clang-tools-extra/docs/ReleaseNotes.rst (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy (+2)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp (+6)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy (+1)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp (+3)
(added) clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h (+1)

diff --git a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
index 4c75b42270114..71e852545203e 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
@@ -311,18 +311,7 @@ ClangTidyDiagnosticConsumer::ClangTidyDiagnosticConsumer(
     : Context(Ctx), ExternalDiagEngine(ExternalDiagEngine),
       RemoveIncompatibleErrors(RemoveIncompatibleErrors),
       GetFixesFromNotes(GetFixesFromNotes),
-      EnableNolintBlocks(EnableNolintBlocks) {
-
-  if (Context.getOptions().HeaderFilterRegex &&
-      !Context.getOptions().HeaderFilterRegex->empty())
-    HeaderFilter =
-        std::make_unique<llvm::Regex>(*Context.getOptions().HeaderFilterRegex);
-
-  if (Context.getOptions().ExcludeHeaderFilterRegex &&
-      !Context.getOptions().ExcludeHeaderFilterRegex->empty())
-    ExcludeHeaderFilter = std::make_unique<llvm::Regex>(
-        *Context.getOptions().ExcludeHeaderFilterRegex);
-}
+      EnableNolintBlocks(EnableNolintBlocks) {}
 
 void ClangTidyDiagnosticConsumer::finalizeLastError() {
   if (!Errors.empty()) {
@@ -571,17 +560,30 @@ void ClangTidyDiagnosticConsumer::checkFilters(SourceLocation Location,
   }
 
   StringRef FileName(File->getName());
-  LastErrorRelatesToUserCode =
-      LastErrorRelatesToUserCode || Sources.isInMainFile(Location) ||
-      (HeaderFilter &&
-       (HeaderFilter->match(FileName) &&
-        !(ExcludeHeaderFilter && ExcludeHeaderFilter->match(FileName))));
+  LastErrorRelatesToUserCode = LastErrorRelatesToUserCode ||
+                               Sources.isInMainFile(Location) ||
+                               (getHeaderFilter()->match(FileName) &&
+                                !getExcludeHeaderFilter()->match(FileName));
 
   unsigned LineNumber = Sources.getExpansionLineNumber(Location);
   LastErrorPassesLineFilter =
       LastErrorPassesLineFilter || passesLineFilter(FileName, LineNumber);
 }
 
+llvm::Regex *ClangTidyDiagnosticConsumer::getHeaderFilter() {
+  if (!HeaderFilter)
+    HeaderFilter =
+        std::make_unique<llvm::Regex>(*Context.getOptions().HeaderFilterRegex);
+  return HeaderFilter.get();
+}
+
+llvm::Regex *ClangTidyDiagnosticConsumer::getExcludeHeaderFilter() {
+  if (!ExcludeHeaderFilter)
+    ExcludeHeaderFilter = std::make_unique<llvm::Regex>(
+        *Context.getOptions().ExcludeHeaderFilterRegex);
+  return ExcludeHeaderFilter.get();
+}
+
 void ClangTidyDiagnosticConsumer::removeIncompatibleErrors() {
   // Each error is modelled as the set of intervals in which it applies
   // replacements. To detect overlapping replacements, we use a sweep line
diff --git a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
index ff42f96a0477b..d6cf6a2b2731e 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
+++ b/clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h
@@ -302,6 +302,10 @@ class ClangTidyDiagnosticConsumer : public DiagnosticConsumer {
   /// context.
   llvm::Regex *getHeaderFilter();
 
+  /// Returns the \c ExcludeHeaderFilter constructed for the options set in the
+  /// context.
+  llvm::Regex *getExcludeHeaderFilter();
+
   /// Updates \c LastErrorRelatesToUserCode and LastErrorPassesLineFilter
   /// according to the diagnostic \p Location.
   void checkFilters(SourceLocation Location, const SourceManager &Sources);
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6cb8d572d3a78..6c1f05009df98 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -94,6 +94,9 @@ Improvements to clang-tidy
 - Improved :program:`clang-tidy-diff.py` script. Add the `-warnings-as-errors`
   argument to treat warnings as errors.
 
+- Fixed bug in :program:`clang-tidy` by which `HeaderFilterRegex` did not take
+  effect when passed via the `.clang-tidy` file.
+
 New checks
 ^^^^^^^^^^
 
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy
new file mode 100644
index 0000000000000..f4210353f94de
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/.clang-tidy
@@ -0,0 +1 @@
+HeaderFilterRegex: '.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp
new file mode 100644
index 0000000000000..79622418d6dff
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.cpp
@@ -0,0 +1,3 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK: foo.h:1:12: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h
new file mode 100644
index 0000000000000..f61d4c2923b50
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/foo.h
@@ -0,0 +1 @@
+struct X { X(int); };
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy
new file mode 100644
index 0000000000000..96706c1428047
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/.clang-tidy
@@ -0,0 +1,2 @@
+InheritParentConfig: true
+HeaderFilterRegex: 'subfolder/.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp
new file mode 100644
index 0000000000000..7576b1af74bfa
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.cpp
@@ -0,0 +1,6 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- -I $(dirname %S) 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK-NOT: foo.h:1:12: warning: single-argument constructors must be marked explicit
+
+#include "bar.h"
+// CHECK: bar.h:1:13: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h
new file mode 100644
index 0000000000000..ee12d00d334dd
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/inheritance/subfolder/bar.h
@@ -0,0 +1 @@
+struct XX { XX(int); };
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy
new file mode 100644
index 0000000000000..f4210353f94de
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/.clang-tidy
@@ -0,0 +1 @@
+HeaderFilterRegex: '.*'
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp
new file mode 100644
index 0000000000000..79622418d6dff
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.cpp
@@ -0,0 +1,3 @@
+// RUN: clang-tidy -checks=-*,google-explicit-constructor %s -- 2>&1 | FileCheck %s
+#include "foo.h"
+// CHECK: foo.h:1:12: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h
new file mode 100644
index 0000000000000..f61d4c2923b50
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/header-filter-from-config/simple/foo.h
@@ -0,0 +1 @@
+struct X { X(int); };

tearfur · 2025-03-29T15:07:57Z

Tested by applying this PR on top of 3e742b5. Works great AFAICT!

# curl -sL 'https://github.com/llvm/llvm-project/pull/133582.diff' | git apply

tearfur · 2025-03-29T18:07:16Z

P.S. Just a heads up that Fixes #118009, #121969, #133453 is not linking this PR to all 3 issues.

They need to be split to 3 Fixes #xxx lines.

clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp

carlosgalvezp · 2025-03-31T06:26:32Z

Was there anything else I should fix @HerrCai0907 ? It would be good to get this in in soon and cherrypick to branch 20.

carlosgalvezp · 2025-04-01T14:30:52Z

Otherwise maybe @PiotrZSL can you review, I believe you reviewed the original PR?

PR llvm#91400 broke the usage of HeaderFilterRegex via config file, because it is now created at a different point in the execution and leads to a different value. The result of that is that using HeaderFilterRegex only in the config file does NOT work, in other words clang-tidy stops triggering warnings on header files, thereby losing a lot of coverage. This patch reverts the logic so that the header filter is created upon calling the getHeaderFilter() function. Additionally, this patch adds 2 unit tests to prevent regressions in the future: - One of them, "simple", tests the most basic use case with a single top-level .clang-tidy file. - The second one, "inheritance", demonstrates that the subfolder only gets warnings from headers within it, and not from parent headers. Fixes llvm#118009, llvm#121969, llvm#133453

HerrCai0907

LGTM.

carlosgalvezp · 2025-04-03T07:34:20Z

@tstellar Any chance we can cherry-pick this to the 20.x branch?

carlosgalvezp · 2025-04-03T08:09:23Z

/cherry-pick 6333fa5

llvmbot · 2025-04-03T08:15:19Z

/pull-request #134215

carlosgalvezp · 2025-04-04T20:59:29Z

...tools-extra/test/clang-tidy/infrastructure/header-filter-from-config-file/simple/.clang-tidy

@@ -0,0 +1 @@
+HeaderFilterRegex: '.*'


It appears this use case was broken by this patch, @HerrCai0907 .

There may be more things to fix.

…lvm#133582) PR llvm#91400 broke the usage of HeaderFilterRegex via config file, because it is now created at a different point in the execution and leads to a different value. The result of that is that using HeaderFilterRegex only in the config file does NOT work, in other words clang-tidy stops triggering warnings on header files, thereby losing a lot of coverage. This patch reverts the logic so that the header filter is created upon calling the getHeaderFilter() function. Additionally, this patch adds 2 unit tests to prevent regressions in the future: - One of them, "simple", tests the most basic use case with a single top-level .clang-tidy file. - The second one, "inheritance", demonstrates that the subfolder only gets warnings from headers within it, and not from parent headers. Fixes llvm#118009 Fixes llvm#121969 Fixes llvm#133453 Co-authored-by: Carlos Gálvez <carlos.galvez@zenseact.com> (cherry picked from commit 6333fa5)

carlosgalvezp requested a review from PiotrZSL March 29, 2025 12:47

llvmbot added clang-tools-extra clang-tidy labels Mar 29, 2025

carlosgalvezp requested review from CongzheUalberta and HerrCai0907 and removed request for CongzheUalberta March 29, 2025 12:47

carlosgalvezp force-pushed the header_filter_regex branch 3 times, most recently from 2ecbd54 to 99abf89 Compare March 29, 2025 13:18

HerrCai0907 reviewed Mar 30, 2025

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clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp Show resolved Hide resolved

carlosgalvezp force-pushed the header_filter_regex branch 2 times, most recently from 7c94ad3 to c2b1748 Compare March 30, 2025 19:04

carlosgalvezp requested review from AaronBallman and LegalizeAdulthood March 31, 2025 12:01

carlosgalvezp requested a review from 5chmidti April 3, 2025 06:23

carlosgalvezp force-pushed the header_filter_regex branch from c2b1748 to 12b63eb Compare April 3, 2025 06:41

HerrCai0907 approved these changes Apr 3, 2025

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carlosgalvezp merged commit 6333fa5 into llvm:main Apr 3, 2025
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carlosgalvezp added this to the LLVM 20.X Release milestone Apr 3, 2025

github-project-automation bot added this to LLVM Release Status Apr 3, 2025

github-project-automation bot moved this to Needs Triage in LLVM Release Status Apr 3, 2025

llvmbot moved this from Needs Triage to Done in LLVM Release Status Apr 3, 2025

carlosgalvezp deleted the header_filter_regex branch April 4, 2025 06:43

carlosgalvezp commented Apr 4, 2025

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carlosgalvezp mentioned this pull request Apr 5, 2025

[clang-tidy] Fix [File|Config]OptionsProvider::getOptions #134502

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[clang-tidy] Fix broken HeaderFilterRegex when read from config file #133582

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[clang-tidy] Fix broken HeaderFilterRegex when read from config file #133582

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