[clang-tools-extra] [clang-tidy] Emit warnings from headers by default (PR #164165)
Baranov Victor via cfe-commits
cfe-commits at lists.llvm.org
Sun Oct 19 08:17:35 PDT 2025
https://github.com/vbvictor created https://github.com/llvm/llvm-project/pull/164165
Closes https://github.com/llvm/llvm-project/issues/158132.
>From 2582871583b632de671ee4a2900bf35726d6b9c4 Mon Sep 17 00:00:00 2001
From: Victor Baranov <bar.victor.2002 at gmail.com>
Date: Sun, 19 Oct 2025 18:16:12 +0300
Subject: [PATCH] [clang-tidy] Emit warnings from headers by default
---
.../clang-tidy/ClangTidyOptions.cpp | 2 +-
.../clang-tidy/tool/ClangTidyMain.cpp | 16 ++++++-----
.../clang-tidy/tool/run-clang-tidy.py | 4 +--
clang-tools-extra/docs/ReleaseNotes.rst | 10 +++++++
clang-tools-extra/docs/clang-tidy/index.rst | 8 +++---
.../abseil/no-internal-dependencies.cpp | 2 +-
.../checkers/abseil/no-namespace.cpp | 2 +-
.../checkers/bugprone/reserved-identifier.cpp | 5 ++--
.../google/upgrade-googletest-case.cpp | 4 +--
.../checkers/modernize/replace-auto-ptr.cpp | 2 +-
.../checkers/modernize/use-using.cpp | 2 +-
.../readability/duplicate-include.cpp | 4 ++-
.../readability/identifier-naming.cpp | 7 ++---
.../infrastructure/default-header-filter.cpp | 27 +++++++++++++++++++
.../clang-tidy/infrastructure/file-filter.cpp | 2 +-
15 files changed, 71 insertions(+), 26 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/infrastructure/default-header-filter.cpp
diff --git a/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp b/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
index 21455db7c7e7b..c4b47a440e44b 100644
--- a/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidyOptions.cpp
@@ -247,7 +247,7 @@ ClangTidyOptions ClangTidyOptions::getDefaults() {
Options.WarningsAsErrors = "";
Options.HeaderFileExtensions = {"", "h", "hh", "hpp", "hxx"};
Options.ImplementationFileExtensions = {"c", "cc", "cpp", "cxx"};
- Options.HeaderFilterRegex = "";
+ Options.HeaderFilterRegex = ".*";
Options.ExcludeHeaderFilterRegex = "";
Options.SystemHeaders = false;
Options.FormatStyle = "none";
diff --git a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
index 64157f530b8c0..5d1e6b24cf38d 100644
--- a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
+++ b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
@@ -93,7 +93,7 @@ Configuration files:
WarningsAsErrors: ''
HeaderFileExtensions: ['', 'h','hh','hpp','hxx']
ImplementationFileExtensions: ['c','cc','cpp','cxx']
- HeaderFilterRegex: ''
+ HeaderFilterRegex: '.*'
FormatStyle: none
InheritParentConfig: true
User: user
@@ -133,13 +133,15 @@ file, if any.
static cl::opt<std::string> HeaderFilter("header-filter", desc(R"(
Regular expression matching the names of the
headers to output diagnostics from. Diagnostics
-from the main file of each translation unit are
-always displayed.
+from the main file and all non-system headers
+of each translation unit are always displayed.
+Set this option to an empty string to disable
+diagnostics from non-system headers.
Can be used together with -line-filter.
This option overrides the 'HeaderFilterRegex'
option in .clang-tidy file, if any.
)"),
- cl::init(""),
+ cl::init(".*"),
cl::cat(ClangTidyCategory));
static cl::opt<std::string> ExcludeHeaderFilter("exclude-header-filter",
@@ -379,9 +381,9 @@ static void printStats(const ClangTidyStats &Stats) {
<< " with check filters";
llvm::errs() << ").\n";
if (Stats.ErrorsIgnoredNonUserCode)
- llvm::errs() << "Use -header-filter=.* to display errors from all "
- "non-system headers. Use -system-headers to display "
- "errors from system headers as well.\n";
+ llvm::errs() << "Use -header-filter=.* or leave it as default to display "
+ "errors from all non-system headers. Use -system-headers "
+ "to display errors from system headers as well.\n";
}
}
diff --git a/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py b/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py
index f495f449b5b30..8050813de3445 100755
--- a/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py
+++ b/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py
@@ -470,8 +470,8 @@ async def main() -> None:
default=None,
help="Regular expression matching the names of the "
"headers to output diagnostics from. Diagnostics from "
- "the main file of each translation unit are always "
- "displayed.",
+ "the main file and all non-system headers of each "
+ "translation unit are always displayed.",
)
parser.add_argument(
"-source-filter",
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index a94dd9737468c..be1fba1c294ed 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -70,6 +70,11 @@ Potentially Breaking Changes
:doc:`bugprone-signed-char-misuse
<clang-tidy/checks/bugprone/signed-char-misuse>`
+- :program:`clang-tidy` now displays warnings from all non-system headers by
+ default. Previously, users had to explicitly opt-in to header warnings using
+ `-header-filter='.*'`. To disable warnings from non-system, set `-header-filter`
+ to an empty string.
+
Improvements to clangd
----------------------
@@ -132,6 +137,11 @@ Improvements to clang-tidy
when run over C files. If ``-std`` is not specified, it defaults to
``c99-or-later``.
+- :program:`clang-tidy` now displays warnings from all non-system headers by
+ default. Previously, users had to explicitly opt-in to header warnings using
+ `-header-filter='.*'`. To disable warnings from non-system, set `-header-filter`
+ to an empty string.
+
- :program:`clang-tidy` no longer attemps to analyze code from system headers
by default, greatly improving performance. This behavior is disabled if the
`SystemHeaders` option is enabled.
diff --git a/clang-tools-extra/docs/clang-tidy/index.rst b/clang-tools-extra/docs/clang-tidy/index.rst
index bd2c40e948f34..260d35392b18e 100644
--- a/clang-tools-extra/docs/clang-tidy/index.rst
+++ b/clang-tools-extra/docs/clang-tidy/index.rst
@@ -216,8 +216,10 @@ An overview of all the command-line options:
.clang-tidy file, if any.
--header-filter=<string> - Regular expression matching the names of the
headers to output diagnostics from. Diagnostics
- from the main file of each translation unit are
- always displayed.
+ from the main file and all non-system headers
+ of each translation unit are always displayed.
+ Set this option to an empty string to disable
+ diagnostics from non-system headers.
Can be used together with -line-filter.
This option overrides the 'HeaderFilterRegex'
option in .clang-tidy file, if any.
@@ -338,7 +340,7 @@ An overview of all the command-line options:
WarningsAsErrors: ''
HeaderFileExtensions: ['', 'h','hh','hpp','hxx']
ImplementationFileExtensions: ['c','cc','cpp','cxx']
- HeaderFilterRegex: ''
+ HeaderFilterRegex: '.*'
FormatStyle: none
InheritParentConfig: true
User: user
diff --git a/clang-tools-extra/test/clang-tidy/checkers/abseil/no-internal-dependencies.cpp b/clang-tools-extra/test/clang-tidy/checkers/abseil/no-internal-dependencies.cpp
index 2949d7fdd0274..f6eb7c5e25949 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/abseil/no-internal-dependencies.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/abseil/no-internal-dependencies.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s abseil-no-internal-dependencies %t, -- -- -I %S/Inputs
+// RUN: %check_clang_tidy %s abseil-no-internal-dependencies %t, -- -header-filter='' -- -I %S/Inputs
// RUN: clang-tidy -checks='-*, abseil-no-internal-dependencies' -header-filter='.*' %s -- -I %S/Inputs 2>&1 | FileCheck %s
#include "absl/strings/internal-file.h"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/abseil/no-namespace.cpp b/clang-tools-extra/test/clang-tidy/checkers/abseil/no-namespace.cpp
index 78821c373f5c4..c8a5752ed86a6 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/abseil/no-namespace.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/abseil/no-namespace.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s abseil-no-namespace %t -- -- -I %S/Inputs
+// RUN: %check_clang_tidy %s abseil-no-namespace %t -- -header-filter='' -- -I %S/Inputs
// RUN: clang-tidy -checks='-*, abseil-no-namespace' -header-filter='.*' %s -- -I %S/Inputs 2>&1 | FileCheck %s
/// Warning will not be triggered on internal Abseil code that is included.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/reserved-identifier.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/reserved-identifier.cpp
index 0f36efe656bf9..b17e8903c41c2 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/reserved-identifier.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/reserved-identifier.cpp
@@ -1,8 +1,9 @@
-// RUN: %check_clang_tidy %s bugprone-reserved-identifier %t -- -- \
+// RUN: %check_clang_tidy %s bugprone-reserved-identifier %t -- \
+// RUN: -header-filter='' -- \
// RUN: -I%S/Inputs/reserved-identifier \
// RUN: -isystem %S/Inputs/reserved-identifier/system
-// no warnings expected without -header-filter=
+// no warnings expected with -header-filter=''
#include "user-header.h"
#include <system-header.h>
diff --git a/clang-tools-extra/test/clang-tidy/checkers/google/upgrade-googletest-case.cpp b/clang-tools-extra/test/clang-tidy/checkers/google/upgrade-googletest-case.cpp
index edb11b9863532..5b30541a96a42 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/google/upgrade-googletest-case.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/google/upgrade-googletest-case.cpp
@@ -1,5 +1,5 @@
-// RUN: %check_clang_tidy %s google-upgrade-googletest-case %t -- -- -I%S/Inputs
-// RUN: %check_clang_tidy -check-suffix=NOSUITE %s google-upgrade-googletest-case %t -- -- -DNOSUITE -I%S/Inputs/gtest/nosuite
+// RUN: %check_clang_tidy %s google-upgrade-googletest-case %t -- -- -isystem%S/Inputs
+// RUN: %check_clang_tidy -check-suffix=NOSUITE %s google-upgrade-googletest-case %t -- -- -DNOSUITE -isystem%S/Inputs/gtest/nosuite
#include "gtest/gtest.h"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/replace-auto-ptr.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/replace-auto-ptr.cpp
index 2281c1acad94f..371f3ddf6d650 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/replace-auto-ptr.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/replace-auto-ptr.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s modernize-replace-auto-ptr %t -- -- -I %S/Inputs/replace-auto-ptr
+// RUN: %check_clang_tidy %s modernize-replace-auto-ptr %t -- -- -isystem %S/Inputs/replace-auto-ptr
// CHECK-FIXES: #include <utility>
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
index 8288f39126a11..5b8eca2825645 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-using.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s modernize-use-using %t -- -- -fno-delayed-template-parsing -I %S/Inputs/use-using/
+// RUN: %check_clang_tidy %s modernize-use-using %t -- -- -fno-delayed-template-parsing -isystem %S/Inputs/use-using/
typedef int Type;
// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: use 'using' instead of 'typedef' [modernize-use-using]
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/duplicate-include.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/duplicate-include.cpp
index 223f07724c5d0..c452f69fad07d 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/duplicate-include.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/duplicate-include.cpp
@@ -1,4 +1,6 @@
-// RUN: %check_clang_tidy %s readability-duplicate-include %t -- -- -isystem %S/Inputs/duplicate-include/system -I %S/Inputs/duplicate-include
+// RUN: %check_clang_tidy %s readability-duplicate-include %t -- \
+// RUN: -header-filter='' \
+// RUN: -- -isystem %S/Inputs/duplicate-include/system -I %S/Inputs/duplicate-include
int a;
#include <string.h>
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming.cpp
index 86502759c2bcd..5b1f9cb3f3c9e 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming.cpp
@@ -82,7 +82,9 @@
// RUN: readability-identifier-naming.LocalPointerPrefix: 'l_', \
// RUN: readability-identifier-naming.LocalConstantPointerCase: CamelCase, \
// RUN: readability-identifier-naming.LocalConstantPointerPrefix: 'lc_', \
-// RUN: }}' -- -fno-delayed-template-parsing -Dbad_macro \
+// RUN: }}' \
+// RUN: -header-filter='' \
+// RUN: -- -fno-delayed-template-parsing -Dbad_macro \
// RUN: -I%S/Inputs/identifier-naming \
// RUN: -isystem %S/Inputs/identifier-naming/system
@@ -91,8 +93,7 @@
#include <system-header.h>
#include <coroutines.h>
#include "user-header.h"
-// NO warnings or fixes expected from declarations within header files without
-// the -header-filter= option
+// NO warnings or fixes expected from declarations with the -header-filter='' option
namespace FOO_NS {
// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: invalid case style for namespace 'FOO_NS' [readability-identifier-naming]
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/default-header-filter.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/default-header-filter.cpp
new file mode 100644
index 0000000000000..a7f22e6cd8e7b
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/default-header-filter.cpp
@@ -0,0 +1,27 @@
+
+// RUN: clang-tidy -checks='-*,google-explicit-constructor' --config='{}' %s -- -I %S/Inputs/file-filter -isystem %S/Inputs/file-filter/system 2>&1 | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: clang-tidy -checks='-*,google-explicit-constructor' --config='{}' -header-filter='' %s -- -I %S/Inputs/file-filter -isystem %S/Inputs/file-filter/system 2>&1 | FileCheck --check-prefix=CHECK-EMPTY %s
+// RUN: clang-tidy -checks='-*,google-explicit-constructor' --config='{}' -header-filter='.*' %s -- -I %S/Inputs/file-filter -isystem %S/Inputs/file-filter/system 2>&1 | FileCheck --check-prefix=CHECK-EXPLICIT %s
+// RUN: clang-tidy -checks='-*,google-explicit-constructor' --config='{}' %s -- -I %S/Inputs/file-filter -isystem %S/Inputs/file-filter/system 2>&1 | FileCheck --check-prefix=CHECK-NO-SYSTEM %s
+// RUN: clang-tidy -checks='-*,google-explicit-constructor' --config='{}' -system-headers %s -- -I %S/Inputs/file-filter -isystem %S/Inputs/file-filter/system 2>&1 | FileCheck --check-prefix=CHECK-WITH-SYSTEM %s
+
+#include "header1.h"
+// CHECK-DEFAULT: header1.h:1:12: warning: single-argument constructors must be marked explicit
+// CHECK-EMPTY-NOT: header1.h:1:12: warning:
+// CHECK-EXPLICIT: header1.h:1:12: warning: single-argument constructors must be marked explicit
+// CHECK-NO-SYSTEM: header1.h:1:12: warning: single-argument constructors must be marked explicit
+// CHECK-WITH-SYSTEM: header1.h:1:12: warning: single-argument constructors must be marked explicit
+
+#include <system-header.h>
+// CHECK-DEFAULT-NOT: system-header.h:1:12: warning:
+// CHECK-EMPTY-NOT: system-header.h:1:12: warning:
+// CHECK-EXPLICIT-NOT: system-header.h:1:12: warning:
+// CHECK-NO-SYSTEM-NOT: system-header.h:1:12: warning:
+// CHECK-WITH-SYSTEM: system-header.h:1:12: warning: single-argument constructors must be marked explicit
+
+class A { A(int); };
+// CHECK-DEFAULT: :[[@LINE-1]]:11: warning: single-argument constructors must be marked explicit
+// CHECK-EMPTY: :[[@LINE-2]]:11: warning: single-argument constructors must be marked explicit
+// CHECK-EXPLICIT: :[[@LINE-3]]:11: warning: single-argument constructors must be marked explicit
+// CHECK-NO-SYSTEM: :[[@LINE-4]]:11: warning: single-argument constructors must be marked explicit
+// CHECK-WITH-SYSTEM: :[[@LINE-5]]:11: warning: single-argument constructors must be marked explicit
diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/file-filter.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/file-filter.cpp
index d9ec1049963b0..485e9fb1f0cb7 100644
--- a/clang-tools-extra/test/clang-tidy/infrastructure/file-filter.cpp
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/file-filter.cpp
@@ -66,7 +66,7 @@ class A { A(int); };
// CHECK4-NOT: warning:
// CHECK4-QUIET-NOT: warning:
-// CHECK: Use -header-filter=.* to display errors from all non-system headers.
+// CHECK: Use -header-filter=.* or leave it as default to display errors from all non-system headers.
// CHECK-QUIET-NOT: Suppressed
// CHECK2-QUIET-NOT: Suppressed
// CHECK3: Use -header-filter=.* {{.*}}
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