[clang-format] Add PenaltyBreakBeforeMemberAccess

Add a configuration option to set the penalty for breaking
before a member access operator.

Author: gedare

clang/include/clang/Format/Format.h

@@ -3639,6 +3639,10 @@ struct FormatStyle {
   /// \version 3.7
   unsigned PenaltyBreakBeforeFirstCallParameter;
 
+  /// The penalty for breaking before a member access operator (``.``, ``->``).
+  /// \version 20
+  unsigned PenaltyBreakBeforeMemberAccess;
+
   /// The penalty for each line break introduced inside a comment.
   /// \version 3.7
   unsigned PenaltyBreakComment;
@@ -5311,6 +5315,7 @@ struct FormatStyle {
            PenaltyBreakAssignment == R.PenaltyBreakAssignment &&
            PenaltyBreakBeforeFirstCallParameter ==
                R.PenaltyBreakBeforeFirstCallParameter &&
+           PenaltyBreakBeforeMemberAccess == R.PenaltyBreakBeforeMemberAccess &&
            PenaltyBreakComment == R.PenaltyBreakComment &&
            PenaltyBreakFirstLessLess == R.PenaltyBreakFirstLessLess &&
            PenaltyBreakOpenParenthesis == R.PenaltyBreakOpenParenthesis &&

clang/lib/Format/Format.cpp

@@ -1091,6 +1091,8 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("PenaltyBreakAssignment", Style.PenaltyBreakAssignment);
     IO.mapOptional("PenaltyBreakBeforeFirstCallParameter",
                    Style.PenaltyBreakBeforeFirstCallParameter);
+    IO.mapOptional("PenaltyBreakBeforeMemberAccess",
+                   Style.PenaltyBreakBeforeMemberAccess);
     IO.mapOptional("PenaltyBreakComment", Style.PenaltyBreakComment);
     IO.mapOptional("PenaltyBreakFirstLessLess",
                    Style.PenaltyBreakFirstLessLess);
@@ -1659,6 +1661,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
 
   LLVMStyle.PenaltyBreakAssignment = prec::Assignment;
   LLVMStyle.PenaltyBreakBeforeFirstCallParameter = 19;
+  LLVMStyle.PenaltyBreakBeforeMemberAccess = 150;
   LLVMStyle.PenaltyBreakComment = 300;
   LLVMStyle.PenaltyBreakFirstLessLess = 120;
   LLVMStyle.PenaltyBreakOpenParenthesis = 0;

clang/lib/Format/TokenAnnotator.cpp

@@ -4314,7 +4314,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
     //   aaaaaaa
     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
-               ? 150
+               ? Style.PenaltyBreakBeforeMemberAccess
                : 35;
   }
 

clang/unittests/Format/ConfigParseTest.cpp

@@ -266,6 +266,8 @@ TEST(ConfigParseTest, ParsesConfiguration) {
   CHECK_PARSE("PenaltyBreakAssignment: 1234", PenaltyBreakAssignment, 1234u);
   CHECK_PARSE("PenaltyBreakBeforeFirstCallParameter: 1234",
               PenaltyBreakBeforeFirstCallParameter, 1234u);
+  CHECK_PARSE("PenaltyBreakBeforeMemberAccess: 1234",
+              PenaltyBreakBeforeMemberAccess, 1234u);
   CHECK_PARSE("PenaltyBreakTemplateDeclaration: 1234",
               PenaltyBreakTemplateDeclaration, 1234u);
   CHECK_PARSE("PenaltyBreakOpenParenthesis: 1234", PenaltyBreakOpenParenthesis,

clang/unittests/Format/FormatTest.cpp

@@ -22365,6 +22365,19 @@ TEST_F(FormatTest, BreakPenaltyAfterForLoopLParen) {
                Style);
 }
 
+TEST_F(FormatTest, BreakPenaltyBeforeMemberAccess) {
+  FormatStyle Style = getLLVMStyle();
+  Style.ColumnLimit = 8;
+  Style.PenaltyExcessCharacter = 15;
+  verifyFormat("foo->bar\n"
+               "    .b(a);",
+               Style);
+  Style.PenaltyBreakBeforeMemberAccess = 200;
+  verifyFormat("foo->bar.b(\n"
+               "    a);",
+               Style);
+}
+
 TEST_F(FormatTest, BreakPenaltyScopeResolution) {
   FormatStyle Style = getLLVMStyle();
   Style.ColumnLimit = 20;