[Format] Don't treat compound extension headers (foo.proto.h) as foo.cc main file.

[hokein]

Summary

We receive internal bugs about this false positives after D86597.

[sammccall]

clang/lib/Tooling/Inclusions/HeaderIncludes.cpp

237

this deserves a comment: Not matchingStem: implementation files may have compound extensions but headers may not.

[hokein]

committed in c1b209cc61290f1ce1243470b825e0994645cb7d.

[rupprecht]

It looks like this fix caused a different regression in not accepting name.<x>.h as the main header for name.<x>.cc, e.g.:

$ cat /tmp/foo.bar.cc
#include "a.h"
#include "z.h"
#include "foo.bar.h"

$ clang-format /tmp/foo.bar.cc  # Before
#include "foo.bar.h"

#include "a.h"
#include "z.h"

$ clang-format /tmp/foo.bar.cc  # After
#include "a.h"
#include "foo.bar.h"
#include "z.h"

[hokein]

In D88640#2339349, @rupprecht wrote:

It looks like this fix caused a different regression in not accepting name.<x>.h as the main header for name.<x>.cc, e.g.:

$ cat /tmp/foo.bar.cc
#include "a.h"
#include "z.h"
#include "foo.bar.h"

$ clang-format /tmp/foo.bar.cc  # Before
#include "foo.bar.h"

#include "a.h"
#include "z.h"

$ clang-format /tmp/foo.bar.cc  # After
#include "a.h"
#include "foo.bar.h"
#include "z.h"

oh, sorry for the regression. Will try to fix that, thanks for the example!

clang/lib/Tooling/Inclusions/HeaderIncludes.cpp

for (unsigned i = 0, e = CategoryRegexs.size(); i != e; ++i)
     }
   if (CheckMainHeader && IsMainFile && Ret > 0 && isMainHeader(IncludeName))
     Ret = 0;
   return Ret;
 }
 bool IncludeCategoryManager::isMainHeader(StringRef IncludeName) const {
   if (!IncludeName.startswith("\""))
     return false;
-  StringRef HeaderStem = matchingStem(IncludeName.drop_front(1).drop_back(1));
+
+  StringRef HeaderStem =
+      llvm::sys::path::stem(IncludeName.drop_front(1).drop_back(
+          1) /* remove the surrounding "" or <> */);
   if (FileStem.startswith(HeaderStem) ||
       FileStem.startswith_lower(HeaderStem)) {
     llvm::Regex MainIncludeRegex(HeaderStem.str() + Style.IncludeIsMainRegex,
                                  llvm::Regex::IgnoreCase);
     if (MainIncludeRegex.match(FileStem))
       return true;
   }
   return false;

clang/unittests/Format/SortIncludesTest.cpp

std::string Code = "#include <a>\n"
                      "#include <b>\n"
                      "#include <c>\n"
                      "#include <d>\n"
                      "#include <e>\n"
                      "#include <f>\n";
   EXPECT_TRUE(sortIncludes(FmtStyle, Code, GetCodeRange(Code), "a.cc").empty());
 }
 
+TEST_F(SortIncludesTest, NoMainFileHeader) {
+  std::string Code = "#include <string>\n"
+                     "\n"
+                     "#include \"a/extra_action.proto.h\"\n";
+  FmtStyle = getGoogleStyle(FormatStyle::LK_Cpp);
+  EXPECT_TRUE(
+      sortIncludes(FmtStyle, Code, GetCodeRange(Code), "a/extra_action.cc")
+          .empty());
+}
+
 TEST_F(SortIncludesTest, SortedIncludesInMultipleBlocksAreMerged) {
   Style.IncludeBlocks = tooling::IncludeStyle::IBS_Merge;
   EXPECT_EQ("#include \"a.h\"\n"
             "#include \"b.h\"\n"
             "#include \"c.h\"\n",
             sort("#include \"a.h\"\n"
                  "#include \"c.h\"\n"
                  "\n"