[clang-tools-extra] [clang-tidy] Fix broken HeaderFilterRegex when read from config file (PR #133582)

Sat Mar 29 05:47:56 PDT 2025

llvmbot wrote:




@llvm/pr-subscribers-clang-tidy

Author: Carlos Galvez (carlosgalvezp)

<details>
<summary>Changes</summary>

PR https://github.com/llvm/llvm-project/pull/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

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); };

``````````

</details>


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