[clang-format] Fix option BreakBinaryOperations for operator >> (llvm#122282)

Fixes llvm#106228.

Author: andergnet

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);

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) {