From e2402615a5a76d46a433dfcc1de10b38a1263c9d Mon Sep 17 00:00:00 2001
From: Ander <github32@anderg.fastmail.com>
Date: Sat, 18 Jan 2025 04:45:10 +0100
Subject: [PATCH] [clang-format] Fix option `BreakBinaryOperations` for
 operator `>>` (#122282)

Fixes #106228.
---
 clang/lib/Format/ContinuationIndenter.cpp |  1 +
 clang/unittests/Format/FormatTest.cpp     | 33 +++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 554b55fa75c92..c311deaa17bb0 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -148,6 +148,7 @@ static bool startsNextOperand(const FormatToken &Current) {
 static bool mustBreakBinaryOperation(const FormatToken &Current,
                                      const FormatStyle &Style) {
   return Style.BreakBinaryOperations != FormatStyle::BBO_Never &&
+         Current.CanBreakBefore &&
          (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None
               ? startsNextOperand
               : isAlignableBinaryOperator)(Current);
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index d3c97319abb94..f8d13cd0ce250 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -27976,6 +27976,11 @@ TEST_F(FormatTest, BreakBinaryOperations) {
                "    operand1 + operand2 - (operand3 + operand4);",
                Style);
 
+  // Check operator>> special case.
+  verifyFormat("std::cin >> longOperand_1 >> longOperand_2 >>\n"
+               "    longOperand_3_;",
+               Style);
+
   Style.BreakBinaryOperations = FormatStyle::BBO_OnePerLine;
 
   // Logical operations
@@ -28054,6 +28059,13 @@ TEST_F(FormatTest, BreakBinaryOperations) {
                "         operand6->member;",
                Style);
 
+  // Check operator>> special case.
+  verifyFormat("std::cin >>\n"
+               "    longOperand_1 >>\n"
+               "    longOperand_2 >>\n"
+               "    longOperand_3_;",
+               Style);
+
   Style.BreakBinaryOperations = FormatStyle::BBO_RespectPrecedence;
   verifyFormat("result = op1 + op2 * op3 - op4;", Style);
 
@@ -28079,6 +28091,13 @@ TEST_F(FormatTest, BreakBinaryOperations) {
                "                  byte_buffer[3] << 24;",
                Style);
 
+  // Check operator>> special case.
+  verifyFormat("std::cin >>\n"
+               "    longOperand_1 >>\n"
+               "    longOperand_2 >>\n"
+               "    longOperand_3_;",
+               Style);
+
   Style.BreakBinaryOperations = FormatStyle::BBO_OnePerLine;
   Style.BreakBeforeBinaryOperators = FormatStyle::BOS_NonAssignment;
 
@@ -28153,6 +28172,13 @@ TEST_F(FormatTest, BreakBinaryOperations) {
                "                  << 24;",
                Style);
 
+  // Check operator>> special case.
+  verifyFormat("std::cin\n"
+               "    >> longOperand_1\n"
+               "    >> longOperand_2\n"
+               "    >> longOperand_3_;",
+               Style);
+
   Style.BreakBinaryOperations = FormatStyle::BBO_RespectPrecedence;
   verifyFormat("result = op1 + op2 * op3 - op4;", Style);
 
@@ -28177,6 +28203,13 @@ TEST_F(FormatTest, BreakBinaryOperations) {
                "                  | byte_buffer[2] << 16\n"
                "                  | byte_buffer[3] << 24;",
                Style);
+
+  // Check operator>> special case.
+  verifyFormat("std::cin\n"
+               "    >> longOperand_1\n"
+               "    >> longOperand_2\n"
+               "    >> longOperand_3_;",
+               Style);
 }
 
 TEST_F(FormatTest, RemoveEmptyLinesInUnwrappedLines) {