[clang] [clang-format] Don't wrap before attributes in parameter lists (PR #132519)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/132519

Fix #132240

>From 16137a72cda66f20cf381b6eb6af11375ef39f92 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Fri, 21 Mar 2025 21:34:52 -0700
Subject: [PATCH] [clang-format] Don't wrap before attributes in parameter
 lists

Fix #132240
---
 clang/lib/Format/TokenAnnotator.cpp   | 14 ++++++++++++++
 clang/unittests/Format/FormatTest.cpp |  6 ++++++
 2 files changed, 20 insertions(+)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 35577cd6db7a1..01bf8c3778928 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -4078,6 +4078,7 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) const {
   }
 
   bool InFunctionDecl = Line.MightBeFunctionDecl;
+  bool InParameterList = false;
   for (auto *Current = First->Next; Current; Current = Current->Next) {
     const FormatToken *Prev = Current->Previous;
     if (Current->is(TT_LineComment)) {
@@ -4132,6 +4133,19 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) const {
 
     Current->CanBreakBefore =
         Current->MustBreakBefore || canBreakBefore(Line, *Current);
+
+    if (Current->is(TT_FunctionDeclarationLParen)) {
+      InParameterList = true;
+    } else if (Current->is(tok::r_paren)) {
+      const auto *LParen = Current->MatchingParen;
+      if (LParen && LParen->is(TT_FunctionDeclarationLParen))
+        InParameterList = false;
+    } else if (InParameterList &&
+               Current->endsSequence(TT_AttributeMacro,
+                                     TT_PointerOrReference)) {
+      Current->CanBreakBefore = false;
+    }
+
     unsigned ChildSize = 0;
     if (Prev->Children.size() == 1) {
       FormatToken &LastOfChild = *Prev->Children[0]->Last;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 5df7865f5a629..7e5b285699d59 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -12664,6 +12664,12 @@ TEST_F(FormatTest, UnderstandsAttributes) {
   verifyFormat("__attr1() ::qualified_type f();", CustomAttrs);
   verifyFormat("__attr1(nodebug) ::qualified_type f();", CustomAttrs);
 
+  CustomAttrs.AttributeMacros.push_back("my_attr_name");
+  verifyFormat("void MyGoodOldFunction(\n"
+               "    void *const long_enough = nullptr,\n"
+               "    void *my_attr_name even_longeeeeeeeeeeeeeeeeer = nullptr);",
+               CustomAttrs);
+
   // Check that these are not parsed as function declarations:
   CustomAttrs.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
   CustomAttrs.BreakBeforeBraces = FormatStyle::BS_Allman;