added option AllowNoNamespaceComments for google-readability-namespace-comments

new option AllowNoNamespaceComments added for
google-readability-namespace-comments.

When true, the check will allow that namespace comments are ommitted
entirely. The check only fails if a namespace comment is present but
does
   not match. Default is `false`.

Author: thorsten-klein

clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.cpp

@@ -28,11 +28,13 @@ NamespaceCommentCheck::NamespaceCommentCheck(StringRef Name,
           "namespace( +(((inline )|([a-zA-Z0-9_:]))+))?\\.? *(\\*/)?$",
           llvm::Regex::IgnoreCase),
       ShortNamespaceLines(Options.get("ShortNamespaceLines", 1U)),
-      SpacesBeforeComments(Options.get("SpacesBeforeComments", 1U)) {}
+      SpacesBeforeComments(Options.get("SpacesBeforeComments", 1U)),
+      AllowNoNamespaceComments(Options.get("AllowNoNamespaceComments", false)) {}
 
 void NamespaceCommentCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "ShortNamespaceLines", ShortNamespaceLines);
   Options.store(Opts, "SpacesBeforeComments", SpacesBeforeComments);
+  Options.store(Opts, "AllowNoNamespaceComments", AllowNoNamespaceComments);
 }
 
 void NamespaceCommentCheck::registerMatchers(MatchFinder *Finder) {
@@ -141,6 +143,7 @@ void NamespaceCommentCheck::check(const MatchFinder::MatchResult &Result) {
 
   SourceRange OldCommentRange(AfterRBrace, AfterRBrace);
   std::string Message = "%0 not terminated with a closing comment";
+  bool hasComment = false;
 
   // Try to find existing namespace closing comment on the same line.
   if (Tok.is(tok::comment) && NextTokenIsOnSameLine) {
@@ -159,6 +162,8 @@ void NamespaceCommentCheck::check(const MatchFinder::MatchResult &Result) {
         return;
       }
 
+      hasComment = true;
+
       // Otherwise we need to fix the comment.
       NeedLineBreak = Comment.starts_with("/*");
       OldCommentRange =
@@ -184,6 +189,11 @@ void NamespaceCommentCheck::check(const MatchFinder::MatchResult &Result) {
       ND->isAnonymousNamespace() ? "anonymous namespace"
                                  : ("namespace '" + *NamespaceNameAsWritten + "'");
 
+  // If no namespace comment is allowed
+  if(!hasComment && AllowNoNamespaceComments) {
+    return;
+  }
+
   std::string Fix(SpacesBeforeComments, ' ');
   Fix.append("// namespace");
   if (!ND->isAnonymousNamespace())

clang-tools-extra/clang-tidy/readability/NamespaceCommentCheck.h

@@ -34,6 +34,7 @@ class NamespaceCommentCheck : public ClangTidyCheck {
   llvm::Regex NamespaceCommentPattern;
   const unsigned ShortNamespaceLines;
   const unsigned SpacesBeforeComments;
+  const bool AllowNoNamespaceComments;
   llvm::SmallVector<SourceLocation, 4> Ends;
 };
 

clang-tools-extra/docs/ReleaseNotes.rst

@@ -287,6 +287,11 @@ Changes in existing checks
   <clang-tidy/checks/cppcoreguidelines/pro-type-union-access>` check to
   report a location even when the member location is not valid.
 
+- Improved :doc:`google-readability-namespace-comments
+  <clang-tidy/checks/google/readability-namespace-comments>` check to
+  add an option ``AllowNoNamespaceComments``, that permits
+  omitting namespace comments entirely.
+
 - Improved :doc:`misc-definitions-in-headers
   <clang-tidy/checks/misc/definitions-in-headers>` check by rewording the
   diagnostic note that suggests adding ``inline``.

clang-tools-extra/docs/clang-tidy/checks/llvm/namespace-comment.rst

@@ -39,3 +39,9 @@ Options
 
    An unsigned integer specifying the number of spaces before the comment
    closing a namespace definition. Default is `1U`.
+
+.. option:: AllowNoNamespaceComments
+
+   When `true`, the check will allow that namespace comments are omitted
+   entirely. The check only fails if a namespace comment is present but does
+   not match namespace definition. Default is `false`.

clang-tools-extra/test/clang-tidy/checkers/google/readability-namespace-comments-missing-c++17.cpp

@@ -0,0 +1,55 @@
+// RUN: %check_clang_tidy %s google-readability-namespace-comments %t -- \
+// RUN:   -config='{CheckOptions: { \
+// RUN:     google-readability-namespace-comments.AllowNoNamespaceComments: true, \
+// RUN:   }}'
+
+namespace n1::n2 {
+namespace /*comment1*/n3/*comment2*/::/*comment3*/inline/*comment4*/n4/*comment5*/ {
+
+// So that namespace is not empty.
+void f();
+
+
+}}
+
+namespace n7::inline n8 {
+// make namespace above 10 lines
+
+void hh();
+
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+} // namespace n7::inline n8
+
+namespace n9::inline n10 {
+// make namespace above 10 lines
+void hh();
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+} // namespace n9::n10
+// CHECK-MESSAGES: :[[@LINE-1]]:2: warning: namespace 'n9::inline n10' ends with a comment that refers to a wrong namespace 'n9::n10' [google-readability-namespace-comments]
+
+
+namespace n11::n12 {
+// make namespace above 10 lines
+void hh();
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+// CHECK-MESSAGES: :[[@LINE+1]]:2: warning: namespace 'n11::n12' ends with a comment that refers to a wrong namespace 'n1::n2' [google-readability-namespace-comments]
+}; // namespace n1::n2
+// CHECK-FIXES: }  // namespace n11::n12

clang-tools-extra/test/clang-tidy/checkers/google/readability-namespace-comments-missing.cpp

@@ -0,0 +1,91 @@
+// RUN: %check_clang_tidy %s google-readability-namespace-comments %t -- \
+// RUN:   -config='{CheckOptions: { \
+// RUN:     google-readability-namespace-comments.AllowNoNamespaceComments: true, \
+// RUN:   }}'
+
+namespace n1 {
+namespace /* a comment */ n2 /* another comment */ {
+
+
+void f(); // So that the namespace isn't empty.
+
+
+}}
+
+#define MACRO macro_expansion
+namespace MACRO {
+void f(); // So that the namespace isn't empty.
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+}
+
+namespace macro_expansion {
+void ff(); // So that the namespace isn't empty.
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+}
+
+namespace [[deprecated("foo")]] namespace_with_attr {
+inline namespace inline_namespace {
+void g();
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+}
+}
+
+namespace [[]] {
+void hh();
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+}
+
+namespace short1 {
+namespace short2 {
+// Namespaces covering 10 lines or fewer
+}
+}
+
+namespace n3 {
+
+
+
+
+
+
+
+
+
+} // namespace n3
+
+namespace n4 {
+void hh();
+// 1
+// 2
+// 3
+// 4
+// 5
+// 6
+// 7
+// CHECK-MESSAGES: :[[@LINE+1]]:2: warning: namespace 'n4' ends with a comment that refers to a wrong namespace 'n5' [google-readability-namespace-comments]
+}; // namespace n5
+// CHECK-FIXES: }  // namespace n4