[clang] Add configuration option PenaltyBreakBeforeMemberAccess (PR #118409)

[Gedare Bloom via cfe-commits]

https://github.com/gedare created https://github.com/llvm/llvm-project/pull/118409

The penalty for breaking before a member access is hard-coded to 150. Add a configuration option to allow setting it.

>From dfa4d88b072e99c1c425b85003090a46ca4ec252 Mon Sep 17 00:00:00 2001
From: Gedare Bloom <gedare at rtems.org>
Date: Mon, 2 Dec 2024 15:16:39 -0700
Subject: [PATCH 1/3] [clang-format] Add PenaltyBreakBeforeMemberAccess

Add a configuration option to set the penalty for breaking
before a member access operator.
---
 clang/include/clang/Format/Format.h        |  5 +++++
 clang/lib/Format/Format.cpp                |  3 +++
 clang/lib/Format/TokenAnnotator.cpp        |  2 +-
 clang/unittests/Format/ConfigParseTest.cpp |  2 ++
 clang/unittests/Format/FormatTest.cpp      | 13 +++++++++++++
 5 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 6383934afa2c40..e1d28ffb20259a 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -3620,6 +3620,10 @@ 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;
@@ -5247,6 +5251,7 @@ struct FormatStyle {
            PenaltyBreakAssignment == R.PenaltyBreakAssignment &&
            PenaltyBreakBeforeFirstCallParameter ==
                R.PenaltyBreakBeforeFirstCallParameter &&
+           PenaltyBreakBeforeMemberAccess == R.PenaltyBreakBeforeMemberAccess &&
            PenaltyBreakComment == R.PenaltyBreakComment &&
            PenaltyBreakFirstLessLess == R.PenaltyBreakFirstLessLess &&
            PenaltyBreakOpenParenthesis == R.PenaltyBreakOpenParenthesis &&
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index ee52972ce66f4a..77930a03228f87 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1076,6 +1076,8 @@ 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);
@@ -1638,6 +1640,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
 
   LLVMStyle.PenaltyBreakAssignment = prec::Assignment;
   LLVMStyle.PenaltyBreakBeforeFirstCallParameter = 19;
+  LLVMStyle.PenaltyBreakBeforeMemberAccess = 150;
   LLVMStyle.PenaltyBreakComment = 300;
   LLVMStyle.PenaltyBreakFirstLessLess = 120;
   LLVMStyle.PenaltyBreakOpenParenthesis = 0;
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index bc5239209f3aab..135c71dbc11ccb 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -4280,7 +4280,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
     //   aaaaaaa
     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
-               ? 150
+               ? Style.PenaltyBreakBeforeMemberAccess
                : 35;
   }
 
diff --git a/clang/unittests/Format/ConfigParseTest.cpp b/clang/unittests/Format/ConfigParseTest.cpp
index 7fc7492271668b..121cc6f8b11e8a 100644
--- a/clang/unittests/Format/ConfigParseTest.cpp
+++ b/clang/unittests/Format/ConfigParseTest.cpp
@@ -261,6 +261,8 @@ 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,
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 250e51b5421664..aa10a0c213a03a 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -22215,6 +22215,19 @@ 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;

>From c2a6586e7512433751fb01680ad2d6a93f5846a5 Mon Sep 17 00:00:00 2001
From: Gedare Bloom <gedare at rtems.org>
Date: Mon, 2 Dec 2024 15:37:09 -0700
Subject: [PATCH 2/3] Update release notes

---
 clang/docs/ReleaseNotes.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0bb2eb820cd726..b6e5dbc97ae602 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -978,6 +978,7 @@ clang-format
   ``Never``, and ``true`` to ``Always``.
 - Adds ``RemoveEmptyLinesInUnwrappedLines`` option.
 - Adds ``KeepFormFeed`` option and set it to ``true`` for ``GNU`` style.
+- Adds ``PenaltyBreakBeforeMemberAccess`` option.
 
 libclang
 --------

>From 4d355658357eeaacd49cdecd0418afd9b00ae6b0 Mon Sep 17 00:00:00 2001
From: Gedare Bloom <gedare at rtems.org>
Date: Mon, 2 Dec 2024 16:06:09 -0700
Subject: [PATCH 3/3] dump format style

---
 clang/docs/ClangFormatStyleOptions.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
index 4be448171699ca..3d38b5a9e3c639 100644
--- a/clang/docs/ClangFormatStyleOptions.rst
+++ b/clang/docs/ClangFormatStyleOptions.rst
@@ -5176,6 +5176,11 @@ the configuration (without a prefix: ``Auto``).
 **PenaltyBreakBeforeFirstCallParameter** (``Unsigned``) :versionbadge:`clang-format 3.7` :ref:`¶ <PenaltyBreakBeforeFirstCallParameter>`
   The penalty for breaking a function call after ``call(``.
 
+.. _PenaltyBreakBeforeMemberAccess:
+
+**PenaltyBreakBeforeMemberAccess** (``Unsigned``) :versionbadge:`clang-format 20` :ref:`¶ <PenaltyBreakBeforeMemberAccess>`
+  The penalty for breaking before a member access operator (``.``, ``->``).
+
 .. _PenaltyBreakComment:
 
 **PenaltyBreakComment** (``Unsigned``) :versionbadge:`clang-format 3.7` :ref:`¶ <PenaltyBreakComment>`