[clang-format] [PR44476] Add space between template and attribute

[MyDeveloperDay]

Summary

https://bugs.llvm.org/show_bug.cgi?id=44476

template <typename T> [[nodiscard]] int a() { return 1; }

gets incorrectly formatted to be

template <typename T>[[nodiscard]] int a() { return 1; }

This revision ensure there is a space between the template and the attribute

[JakeMerdichAMD]

One spelling nit, but otherwise looks good to me.

clang/lib/Format/TokenAnnotator.cpp

2900

Nit: template

[MyDeveloperDay]

Correct the typo

[JakeMerdichAMD]

LGTM

clang/lib/Format/TokenAnnotator.cpp

bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
   if ((Left.is(tok::l_brace) && Left.BlockKind != BK_Block) ||
       (Right.is(tok::r_brace) && Right.MatchingParen &&
        Right.MatchingParen->BlockKind != BK_Block))
     return Style.Cpp11BracedListStyle ? Style.SpacesInParentheses : true;
   if (Left.is(TT_BlockComment))
     // No whitespace in x(/*foo=*/1), except for JavaScript.
     return Style.Language == FormatStyle::LK_JavaScript ||
            !Left.TokenText.endswith("=*/");
+
+  // Space between template and attribute.
+  // e.g. template <typename T> [[nodiscard]] ...
+  if (Left.is(TT_TemplateCloser) && Right.is(TT_AttributeSquare))
+    return true;
   if (Right.is(tok::l_paren)) {
     if ((Left.is(tok::r_paren) && Left.is(TT_AttributeParen)) ||
         (Left.is(tok::r_square) && Left.is(TT_AttributeSquare)))
       return true;
     if (Style.SpaceBeforeParens ==
             FormatStyle::SBPO_ControlStatementsExceptForEachMacros &&
         Left.is(TT_ForEachMacro))
       return false;

clang/unittests/Format/FormatTest.cpp

TEST_F(FormatTest, UnderstandsSquareAttributes) {
   verifyFormat("int a = std::vector<int>{1, 2, 3}[0];");
 
   // Make sure that we do not mistake Objective-C method inside array literals
   // as attributes, even if those method names are also keywords.
   verifyFormat("@[ [foo bar] ];");
   verifyFormat("@[ [NSArray class] ];");
   verifyFormat("@[ [foo enum] ];");
 
+  verifyFormat("template <typename T> [[nodiscard]] int a() { return 1; }");
+
   // Make sure we do not parse attributes as lambda introducers.
   FormatStyle MultiLineFunctions = getLLVMStyle();
   MultiLineFunctions.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
   verifyFormat("[[unused]] int b() {\n"
                "  return 42;\n"
                "}\n",
                MultiLineFunctions);
 }