[clang-tidy] Make header-guard check a little looser on comment whitespace

[sammccall]

Summary

Currently it rejects "// FOO_BAR_H" as an endif comment due to the extra space.
A user complained that this is too picky, which seems fair enough.

[hokein]

I think "// FOO_BAR_H" in your message should be "// FOO_BAR_H" (two space).

[sammccall]

In D124955#3493761, @hokein wrote:

I think "// FOO_BAR_H" in your message should be "// FOO_BAR_H" (two space).

It's actually correct in the commit message, just phab renders it wrong :-(

clang-tools-extra/clang-tidy/utils/HeaderGuard.cpp

bool wouldFixEndifComment(StringRef FileName, SourceLocation EndIf,
     EndIfStr = EndIfStr.substr(EndIfStr.find_first_not_of("#endif \t"));
 
     // Give up if there's an escaped newline.
     size_t FindEscapedNewline = EndIfStr.find_last_not_of(' ');
     if (FindEscapedNewline != StringRef::npos &&
         EndIfStr[FindEscapedNewline] == '\\')
       return false;
 
-    if (!Check->shouldSuggestEndifComment(FileName) &&
-        !(EndIfStr.startswith("//") ||
-          (EndIfStr.startswith("/*") && EndIfStr.endswith("*/"))))
-      return false;
+    bool IsLineComment =
+        EndIfStr.consume_front("//") ||
+        (EndIfStr.consume_front("/*") && EndIfStr.consume_back("*/"));
+    if (!IsLineComment)
+      return Check->shouldSuggestEndifComment(FileName);
 
-    return (EndIfStr != "// " + HeaderGuard.str()) &&
-           (EndIfStr != "/* " + HeaderGuard.str() + " */");
+    return EndIfStr.trim() != HeaderGuard;
   }
 
   /// Look for header guards that don't match the preferred style. Emit
   /// fix-its and return the suggested header guard (or the original if no
   /// change was made.
   std::string checkHeaderGuardDefinition(SourceLocation Ifndef,
                                          SourceLocation Define,
                                          SourceLocation EndIf,

clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp

EXPECT_EQ("#ifndef LLVM_ADT_FOO_H\n"
             "#endif // LLVM_ADT_FOO_H\n",
             runHeaderGuardCheckWithEndif(
                 "#ifndef LLVM_ADT_FOO_H_\n"
                 "#define LLVM_ADT_FOO_H_\n"
                 "#endif // LLVM\n",
                 "include/llvm/ADT/foo.h",
                 StringRef("header guard does not follow preferred style")));
 
+  // An extra space inside the comment is OK.
+  llvm::StringRef WithExtraSpace = "#ifndef LLVM_ADT_FOO_H\n"
+                                   "#define LLVM_ADT_FOO_H\n"
+                                   "#endif //  LLVM_ADT_FOO_H\n";
+  EXPECT_EQ(WithExtraSpace,
+            runHeaderGuardCheckWithEndif(WithExtraSpace,
+                                         "include/llvm/ADT/foo.h", None));
+
   EXPECT_EQ("#ifndef LLVM_ADT_FOO_H\n"
             "#define LLVM_ADT_FOO_H\n"
             "#endif \\ \n"
             "// LLVM_ADT_FOO_H\n",
             runHeaderGuardCheckWithEndif(
                 "#ifndef LLVM_ADT_FOO_H\n"
                 "#define LLVM_ADT_FOO_H\n"
                 "#endif \\ \n"