[clang] [clang-format] Fix idempotent format of hash in macro body (PR #118513)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/118513

Fixes #118334.

>From 309952ef482ccbef6cd13f90388139db435b4368 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Tue, 3 Dec 2024 08:51:13 -0800
Subject: [PATCH] [clang-format] Fix idempotent format of hash in macro body

Fixes #118334.
---
 clang/lib/Format/UnwrappedLineParser.cpp      |  2 +-
 clang/unittests/Format/FormatTest.cpp         | 18 ++++++++++++++++++
 clang/unittests/Format/TokenAnnotatorTest.cpp | 19 +++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index c182aaf0876d1b..de7e261b21d303 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -512,7 +512,7 @@ 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/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 250e51b5421664..6fd4f1540f7532 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5724,6 +5724,24 @@ TEST_F(FormatTest, HashInMacroDefinition) {
                getLLVMStyleWithColumns(22));
 
   verifyFormat("#define A void # ## #", getLLVMStyleWithColumns(22));
+
+#if 0
+  // FIXME: The correct format is:
+  verifyFormat("{\n"
+               "  {\n"
+               "#define GEN_ID(_x) char *_x{#_x}\n"
+               "    GEN_ID(one);\n"
+               "  }\n"
+               "}");
+#endif
+  verifyFormat("{\n"
+               "  {\n"
+               "#define GEN_ID(_x) \\\n"
+               "  char *_x { #_x }\n"
+               "    GEN_ID(one);\n"
+               "  }\n"
+               "}",
+               getGoogleStyle());
 }
 
 TEST_F(FormatTest, RespectWhitespaceInMacroDefinitions) {
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 9db3187ac44e70..38658fcb0e9990 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -3346,6 +3346,25 @@ TEST_F(TokenAnnotatorTest, BraceKind) {
   EXPECT_BRACE_KIND(Tokens[11], BK_BracedInit);
   EXPECT_BRACE_KIND(Tokens[13], BK_Block);
 
+  Tokens = annotate("{\n"
+                    "  {\n"
+                    "#define GEN_ID(_x) char *_x{#_x}\n"
+                    "    GEN_ID(one);\n"
+                    "  }\n"
+                    "}");
+  ASSERT_EQ(Tokens.size(), 23u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::l_brace, TT_BlockLBrace);
+  EXPECT_BRACE_KIND(Tokens[0], BK_Block);
+  EXPECT_TOKEN(Tokens[1], tok::l_brace, TT_BlockLBrace);
+  EXPECT_BRACE_KIND(Tokens[1], BK_Block);
+#if 0
+  // FIXME:
+  EXPECT_BRACE_KIND(Tokens[11], BK_BracedInit);
+  EXPECT_BRACE_KIND(Tokens[14], BK_BracedInit);
+#endif
+  EXPECT_BRACE_KIND(Tokens[20], BK_Block);
+  EXPECT_BRACE_KIND(Tokens[21], BK_Block);
+
   Tokens = annotate("a = class extends goog.a {};",
                     getGoogleStyle(FormatStyle::LK_JavaScript));
   ASSERT_EQ(Tokens.size(), 11u) << Tokens;