[clang-format] Fix a bug in annotating StartOfName

[owenca]

Fixes #99758.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

Fixes #99758.

---

Full diff: https://github.com/llvm/llvm-project/pull/99791.diff

2 Files Affected:

• (modified) clang/lib/Format/TokenAnnotator.cpp (+3-1)
• (modified) clang/unittests/Format/TokenAnnotatorTest.cpp (+14)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index db66911f00f63..06c34bd45eb31 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2625,8 +2625,10 @@ class AnnotatingParser {
       return false;
 
     // int a or auto a.
-    if (PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto))
+    if (PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto) &&
+        PreviousNotConst->isNot(TT_StatementAttributeLikeMacro)) {
       return true;
+    }
 
     // *a or &a or &&a.
     if (PreviousNotConst->is(TT_PointerOrReference))
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index f70424c3ee060..e7bc15d7e1dfa 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -2125,6 +2125,13 @@ TEST_F(TokenAnnotatorTest, UnderstandsTrailingReturnArrow) {
   ASSERT_EQ(Tokens.size(), 21u) << Tokens;
   EXPECT_TOKEN(Tokens[13], tok::arrow, TT_Unknown);
 
+  auto Style = getLLVMStyle();
+  Style.StatementAttributeLikeMacros.push_back("emit");
+  Tokens = annotate("emit foo()->bar;", Style);
+  ASSERT_EQ(Tokens.size(), 8u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::identifier, TT_StatementAttributeLikeMacro);
+  EXPECT_TOKEN(Tokens[4], tok::arrow, TT_Unknown);
+
   // Mixed
   Tokens = annotate("auto f() -> int { auto a = b()->c; }");
   ASSERT_EQ(Tokens.size(), 18u) << Tokens;
@@ -2950,6 +2957,13 @@ TEST_F(TokenAnnotatorTest, StartOfName) {
   ASSERT_EQ(Tokens.size(), 7u) << Tokens;
   EXPECT_TOKEN(Tokens[0], tok::at, TT_ObjCDecl);
   EXPECT_TOKEN(Tokens[2], tok::identifier, TT_StartOfName);
+
+  auto Style = getLLVMStyle();
+  Style.StatementAttributeLikeMacros.push_back("emit");
+  Tokens = annotate("emit foo = 0;", Style);
+  ASSERT_EQ(Tokens.size(), 6u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::identifier, TT_StatementAttributeLikeMacro);
+  EXPECT_TOKEN(Tokens[1], tok::identifier, TT_Unknown);
 }
 
 TEST_F(TokenAnnotatorTest, BraceKind) {

[alex1701c]

Can we expect this to be backported and released with clang-format-18?

[owenca]

Unfortunately no because clang-format is part of llvm, and as far as I know there will be no more llvm 18 point releases.

[alex1701c]

That is very unfortunate. It means one will either get different results for the clang-format versions, one disables the formatting, or works around it by sth. Like Q_EMIT(something()->mySignal()).

[owenca]

That is very unfortunate. It means one will either get different results for the clang-format versions, one disables the formatting, or works around it by sth. Like Q_EMIT(something()->mySignal()).

Or wait for the next release (in this case 19.1.0, which is just around the corner).

[alex1701c]

But that does not mean everyone who works on the projects will update to that version right away :(

[owenca]

Wouldn't you have the same problem if we were to backport the fix, say, to 18.1.9? Anyway, LLVM 19.1.0 has just been released.

[alex1701c]

I think it would be normal for distros to backport bugfixes. Thus, users should get the new version rather soonish.