release/18.x: [clang-format] Don't always break before << between str…

[owenca]

…ing literals (#92214)

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

…ing literals (#92214)

---

Full diff: https://github.com/llvm/llvm-project/pull/94091.diff

2 Files Affected:

• (modified) clang/lib/Format/TokenAnnotator.cpp (+5-3)
• (modified) clang/unittests/Format/FormatTest.cpp (+11)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index c1f1662481922..628fe46cc348e 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -5159,9 +5159,11 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
     return true;
   if (Left.IsUnterminatedLiteral)
     return true;
-  if (Right.is(tok::lessless) && Right.Next && Left.is(tok::string_literal) &&
-      Right.Next->is(tok::string_literal)) {
-    return true;
+  if (const auto *BeforeLeft = Left.Previous, *AfterRight = Right.Next;
+      BeforeLeft && BeforeLeft->is(tok::lessless) &&
+      Left.is(tok::string_literal) && Right.is(tok::lessless) && AfterRight &&
+      AfterRight->is(tok::string_literal)) {
+    return Right.NewlinesBefore > 0;
   }
   if (Right.is(TT_RequiresClause)) {
     switch (Style.RequiresClausePosition) {
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 0161a1685eb12..d69632f7f0f8c 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -10426,6 +10426,17 @@ TEST_F(FormatTest, KeepStringLabelValuePairsOnALine) {
       "                  bbbbbbbbbbbbbbbbbbbbbbb);");
 }
 
+TEST_F(FormatTest, WrapBeforeInsertionOperatorbetweenStringLiterals) {
+  verifyFormat("QStringList() << \"foo\" << \"bar\";");
+
+  verifyNoChange("QStringList() << \"foo\"\n"
+                 "              << \"bar\";");
+
+  verifyFormat("log_error(log, \"foo\" << \"bar\");",
+               "log_error(log, \"foo\"\n"
+               "                   << \"bar\");");
+}
+
 TEST_F(FormatTest, UnderstandsEquals) {
   verifyFormat(
       "aaaaaaaaaaaaaaaaa =\n"

[owenca]

@tstellar can we also get this one into 18.1.7?

[tstellar]

@owenca I'm only going to take regression fixes for 18.1.7.

[owenca]

@tstellar strictly speaking, this is a regression fix. (It's a churn within 18.x release cycle.)

1. Risk level: low IMO. (The other code owner @mydeveloperday approved it to be included in 18.1.7.)
2. Last known working version: 18.1.4

[tstellar]

@owenca Do you have a release note we can put in the release announcement?

[owenca]

@tstellar thanks!

@owenca Do you have a release note we can put in the release announcement?

Release note:
Fixes clang-format (since 18.1.1) regressions on breaking before a stream insertion operator (<<) when both operands are string literals.