release/20.x: [clang-format] Fix mismatched break in BlockIndent (#124998)

clang/lib/Format/ContinuationIndenter.cpp

@@ -349,6 +349,13 @@ bool ContinuationIndenter::canBreak(const LineState &State) {
     }
   }
 
+  // Allow breaking before the right parens with block indentation if there was
+  // a break after the left parens, which is tracked by BreakBeforeClosingParen.
+  if (Style.AlignAfterOpenBracket == FormatStyle::BAS_BlockIndent &&
+      Current.is(tok::r_paren)) {
+    return CurrentState.BreakBeforeClosingParen;
+  }
+
   // Don't allow breaking before a closing brace of a block-indented braced list
   // initializer if there isn't already a break.
   if (Current.is(tok::r_brace) && Current.MatchingParen &&

clang/unittests/Format/FormatTest.cpp

@@ -9614,6 +9614,10 @@ TEST_F(FormatTest, AlignsAfterOpenBracket) {
                "        auto aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
                "    ) {};",
                Style);
+  verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaa(\n"
+               "    &bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n"
+               ");",
+               Style);
 }
 
 TEST_F(FormatTest, ParenthesesAndOperandAlignment) {