[clang] [clang-format] Fix a bug in annotating braces (PR #127306)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/127306

Fixes #107616.

>From ffaf13f5f7dc2a2f26ce9dea069533f63ae40f38 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Fri, 14 Feb 2025 23:53:20 -0800
Subject: [PATCH] [clang-format] Fix a bug in annotating braces

Fixes #107616.
---
 clang/lib/Format/UnwrappedLineParser.cpp      |  2 +-
 clang/unittests/Format/TokenAnnotatorTest.cpp | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 4e040183f2f0a..3a24d72d83e27 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -510,7 +510,7 @@ void UnwrappedLineParser::calculateBraceTypes(bool ExpectClassBody) {
           break;
         do {
           NextTok = Tokens->getNextToken();
-        } while (NextTok->NewlinesBefore == 0 && NextTok->isNot(tok::eof));
+        } while (!NextTok->HasUnescapedNewline && NextTok->isNot(tok::eof));
 
         while (NextTok->is(tok::comment))
           NextTok = Tokens->getNextToken();
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 7b489b1764cb2..1d0870c818acc 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -3519,6 +3519,19 @@ TEST_F(TokenAnnotatorTest, BraceKind) {
   EXPECT_BRACE_KIND(Tokens[11], BK_Block);
   EXPECT_BRACE_KIND(Tokens[12], BK_Block);
 
+  Tokens = annotate("class foo {\n"
+                    "  foo() {}\n"
+                    "#if defined(_MSC_VER__clang____GNUC__FOO_) || \\\n"
+                    "    (defined(__GNUC__) && defined(FOO))\n"
+                    "  foo() {}\n"
+                    "#endif\n"
+                    "};");
+  ASSERT_EQ(Tokens.size(), 36u) << Tokens;
+  EXPECT_TOKEN(Tokens[6], tok::l_brace, TT_FunctionLBrace);
+  EXPECT_BRACE_KIND(Tokens[7], BK_Block);
+  EXPECT_TOKEN(Tokens[26], tok::identifier, TT_CtorDtorDeclName);
+  EXPECT_TOKEN(Tokens[27], tok::l_paren, TT_FunctionDeclarationLParen);
+
   Tokens = annotate("a = class extends goog.a {};",
                     getGoogleStyle(FormatStyle::LK_JavaScript));
   ASSERT_EQ(Tokens.size(), 11u) << Tokens;