[clang-format] PR42434 Remove preprocessor and pragma lines from ObjectiveC guess

[MyDeveloperDay]

Summary

clang-format see the disable: in __pragma(warning(disable:)) as ObjectiveC method call

Remove any line starting with # or __pragma line from being part of the ObjectiveC guess

https://bugs.llvm.org/show_bug.cgi?id=42434

[curdeius]

clang/lib/Format/Format.cpp

2037

Maybe you should also handle MS-specific _Pragma?
https://docs.microsoft.com/en-us/cpp/preprocessor/pragma-directives-and-the-pragma-keyword?view=msvc-160

[MyDeveloperDay]

add support for additional _Pragma

[krasimir]

This is very nice :)

[curdeius]

Great! LGTM.

clang/lib/Format/Format.cpp

static constexpr llvm::StringLiteral FoundationIdentifiers[] = {
         "NSURLQueryItem",
         "NSUUID",
         "NSValue",
         "UIImage",
         "UIView",
     };
 
     for (auto Line : AnnotatedLines) {
+      if (Line->First && (Line->First->TokenText.startswith("#") ||
+                          Line->First->TokenText == "__pragma" ||
+                          Line->First->TokenText == "_Pragma"))
+        continue;
       for (const FormatToken *FormatTok = Line->First; FormatTok;
            FormatTok = FormatTok->Next) {
         if ((FormatTok->Previous && FormatTok->Previous->is(tok::at) &&
              (FormatTok->Tok.getObjCKeywordID() != tok::objc_not_keyword ||
               FormatTok->isOneOf(tok::numeric_constant, tok::l_square,
                                  tok::l_brace))) ||
             (FormatTok->Tok.isAnyIdentifier() &&
              std::binary_search(std::begin(FoundationIdentifiers),

clang/unittests/Format/FormatTest.cpp

EXPECT_EQ(FormatStyle::LK_ObjC,
             guessLanguage("foo.h", "int(^foo[10])(char, float);"));
   EXPECT_EQ(FormatStyle::LK_ObjC,
             guessLanguage("foo.h", "int(^foo[kNumEntries])(char, float);"));
   EXPECT_EQ(
       FormatStyle::LK_ObjC,
       guessLanguage("foo.h", "int(^foo[(kNumEntries + 10)])(char, float);"));
 }
 
+TEST_F(FormatTest, GuessLanguageWithPragmas) {
+  EXPECT_EQ(FormatStyle::LK_Cpp,
+            guessLanguage("foo.h", "__pragma(warning(disable:))"));
+  EXPECT_EQ(FormatStyle::LK_Cpp,
+            guessLanguage("foo.h", "#pragma(warning(disable:))"));
+  EXPECT_EQ(FormatStyle::LK_Cpp,
+            guessLanguage("foo.h", "_Pragma(warning(disable:))"));
+}
+
 TEST_F(FormatTest, FormatsInlineAsmSymbolicNames) {
   // ASM symbolic names are identifiers that must be surrounded by [] without
   // space in between:
   // https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#InputOperands
 
   // Example from https://bugs.llvm.org/show_bug.cgi?id=45108.
   verifyFormat(R"(//
 asm volatile("mrs %x[result], FPCR" : [result] "=r"(result));