[clang-tidy] Emit warnings from user headers by default (#164165)

Closes #158132.

Author: vbvictor

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";

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
@@ -132,14 +132,16 @@ 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
+headers to output diagnostics from. The default
+value is '.*', i.e. diagnostics from all non-system
+headers are displayed by default. Diagnostics
 from the main file of each translation unit are
 always displayed.
 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";
   }
 }
 

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 attempts to analyze code from system headers
   by default, greatly improving performance. This behavior is disabled if the
   `SystemHeaders` option is enabled.

clang-tools-extra/docs/clang-tidy/index.rst

@@ -215,7 +215,9 @@ An overview of all the command-line options:
                                        This option overrides the 'FormatStyle` option in
                                        .clang-tidy file, if any.
     --header-filter=<string>         - Regular expression matching the names of the
-                                       headers to output diagnostics from. Diagnostics
+                                       headers to output diagnostics from. The default
+                                       value is '.*', i.e. diagnostics from all non-system
+                                       headers are displayed by default. Diagnostics
                                        from the main file of each translation unit are
                                        always displayed.
                                        Can be used together with -line-filter.
@@ -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

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"

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.

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>
 

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"
 

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>
 

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]