[clang] [clang-format] Fix a bug in BCIS_AfterColon and `ColumnLimit: 0` (PR #127964)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/127964

Fixes #127622

>From 062d6736b517d0d33eeab63c7c33053f72640c3c Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Wed, 19 Feb 2025 23:26:12 -0800
Subject: [PATCH] [clang-format] Fix a bug in BCIS_AfterColon and `ColumnLimit:
 0`

Fixes #127622
---
 clang/lib/Format/ContinuationIndenter.cpp |  5 +--
 clang/unittests/Format/FormatTest.cpp     | 53 +++++++++++++----------
 2 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 3e51b4aab1082..d49128c2b40f8 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -473,9 +473,8 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
       (State.Column + State.Line->Last->TotalLength - Previous.TotalLength >
            getColumnLimit(State) ||
        CurrentState.BreakBeforeParameter) &&
-      (!Current.isTrailingComment() || Current.NewlinesBefore > 0) &&
-      (Style.BreakConstructorInitializers != FormatStyle::BCIS_BeforeColon ||
-       Style.ColumnLimit > 0 || Current.NewlinesBefore > 0)) {
+      ((!Current.isTrailingComment() && Style.ColumnLimit > 0) ||
+       Current.NewlinesBefore > 0)) {
     return true;
   }
 
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index d6d028436d39c..132264486100d 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -8292,31 +8292,40 @@ TEST_F(FormatTest, BreakConstructorInitializersAfterColon) {
                Style);
 
   Style.ColumnLimit = 0;
-  verifyFormat("SomeClass::Constructor() :\n"
-               "    a(a) {}",
-               Style);
-  verifyFormat("SomeClass::Constructor() noexcept :\n"
-               "    a(a) {}",
-               Style);
-  verifyFormat("SomeClass::Constructor() :\n"
-               "    a(a), b(b), c(c) {}",
-               Style);
-  verifyFormat("SomeClass::Constructor() :\n"
-               "    a(a) {\n"
-               "  foo();\n"
-               "  bar();\n"
-               "}",
+  verifyNoChange("SomeClass::Constructor() :\n"
+                 "    a(a) {}",
+                 Style);
+  verifyNoChange("SomeClass::Constructor() noexcept :\n"
+                 "    a(a) {}",
+                 Style);
+  verifyNoChange("SomeClass::Constructor() :\n"
+                 "    a(a), b(b), c(c) {}",
+                 Style);
+  verifyNoChange("SomeClass::Constructor() :\n"
+                 "    a(a) {\n"
+                 "  foo();\n"
+                 "  bar();\n"
+                 "}",
+                 Style);
+  verifyFormat("struct Foo {\n"
+               "  int x;\n"
+               "  Foo() : x(0) {}\n"
+               "};",
+               "struct Foo {\n"
+               "  int x;\n"
+               "  Foo():x(0) {}\n"
+               "};",
                Style);
 
   Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
-  verifyFormat("SomeClass::Constructor() :\n"
-               "    a(a), b(b), c(c) {\n"
-               "}",
-               Style);
-  verifyFormat("SomeClass::Constructor() :\n"
-               "    a(a) {\n"
-               "}",
-               Style);
+  verifyNoChange("SomeClass::Constructor() :\n"
+                 "    a(a), b(b), c(c) {\n"
+                 "}",
+                 Style);
+  verifyNoChange("SomeClass::Constructor() :\n"
+                 "    a(a) {\n"
+                 "}",
+                 Style);
 
   Style.ColumnLimit = 80;
   Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_All;