[clang] [clang-format] Fix ColumnLimit violation while aligning (PR #165627)

[Björn Schäpers via cfe-commits]

https://github.com/HazardyKnusperkeks created https://github.com/llvm/llvm-project/pull/165627

It did compute the length only on the first line, and thus the following lines could be (and in the test example were) moved over the column limit, when the = was aligned.

>From c03e9748780cd980afaa5862164feae37afa751d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Sch=C3=A4pers?= <bjoern at hazardy.de>
Date: Wed, 29 Oct 2025 22:29:15 +0100
Subject: [PATCH] [clang-format] Fix ColumnLimit violation while aligning

It did compute the length only on the first line, and thus the following
lines could be (and in the test example were) moved over the column
limit, when the = was aligned.
---
 clang/lib/Format/WhitespaceManager.cpp | 3 ++-
 clang/unittests/Format/FormatTest.cpp  | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Format/WhitespaceManager.cpp b/clang/lib/Format/WhitespaceManager.cpp
index f24b8ab14bdce..406c77cb3ae8f 100644
--- a/clang/lib/Format/WhitespaceManager.cpp
+++ b/clang/lib/Format/WhitespaceManager.cpp
@@ -591,7 +591,8 @@ static unsigned AlignTokens(const FormatStyle &Style, F &&Matches,
       CurrentChangeWidthRight = CurrentChange.TokenLength;
     const FormatToken *MatchingParenToEncounter = nullptr;
     for (unsigned J = I + 1;
-         J != E && (Changes[J].NewlinesBefore == 0 || MatchingParenToEncounter);
+         J != E && (Changes[J].NewlinesBefore == 0 ||
+                    MatchingParenToEncounter || Changes[J].IsAligned);
          ++J) {
       const auto &Change = Changes[J];
       const auto *Tok = Change.Tok;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index d45babe1b82ad..84a50f76c5902 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -20820,6 +20820,13 @@ TEST_F(FormatTest, AlignWithLineBreaks) {
                "    argument1,\n"
                "    argument2);",
                Style);
+
+  Style.ColumnLimit = 45;
+  verifyFormat("auto xxxxxxxx = foo;\n"
+               "auto x = whatever ? some / long -\n"
+               "                        computition / stuff\n"
+               "                  : random;",
+               Style);
 }
 
 TEST_F(FormatTest, AlignWithInitializerPeriods) {