From 7a474af66601280b22668c9fcfea2b3266c317a0 Mon Sep 17 00:00:00 2001
From: Daniel Jasper <djasper@google.com>
Date: Fri, 21 Mar 2014 12:38:57 +0000
Subject: [PATCH] clang-format: Let a trailing comma in braced lists enforce
 linebreaks.

Before:
  vector<int> x{1, 2, 3, 4, };

After:
  vector<int> x{
      1, 2, 3, 4,
  };

This fixes llvm.org/PR18519.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204458 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Format/TokenAnnotator.cpp   |  8 ++++++++
 unittests/Format/FormatTest.cpp | 14 ++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index c3cc000044..efb983e736 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -1478,6 +1478,7 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
 
 bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
                                      const FormatToken &Right) {
+  const FormatToken &Left = *Right.Previous;
   if (Right.is(tok::comment)) {
     return Right.Previous->BlockKind != BK_BracedInit &&
            Right.Previous->Type != TT_CtorInitializerColon &&
@@ -1514,6 +1515,13 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
              Style.Language == FormatStyle::LK_Proto) {
     // Don't enums onto single lines in protocol buffers.
     return true;
+  } else if ((Left.is(tok::l_brace) && Left.MatchingParen &&
+              Left.MatchingParen->Previous &&
+              Left.MatchingParen->Previous->is(tok::comma)) ||
+             (Right.is(tok::r_brace) && Left.is(tok::comma))) {
+    // If the last token before a '}' is a comma, the intention is to insert a
+    // line break after it in order to make shuffling around entries easier.
+    return true;
   }
   return false;
 }
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index bd926f63a6..e1b72d9a99 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -4901,6 +4901,9 @@ TEST_F(FormatTest, LayoutBraceInitializersInReturnStatement) {
 
 TEST_F(FormatTest, LayoutCxx11ConstructorBraceInitializers) {
   verifyFormat("vector<int> x{1, 2, 3, 4};");
+  verifyFormat("vector<int> x{\n"
+               "    1, 2, 3, 4,\n"
+               "};");
   verifyFormat("vector<T> x{{}, {}, {}, {}};");
   verifyFormat("f({1, 2});");
   verifyFormat("auto v = Foo{-1};");
@@ -5036,8 +5039,9 @@ TEST_F(FormatTest, FormatsBracedListsInColumnLayout) {
                getLLVMStyleWithColumns(43));
 
   // Trailing commas.
-  verifyFormat("vector<int> x = {1, 1, 1, 1,\n"
-               "                 1, 1, 1, 1, };",
+  verifyFormat("vector<int> x = {\n"
+               "    1, 1, 1, 1, 1, 1, 1, 1,\n"
+               "};",
                getLLVMStyleWithColumns(39));
   verifyFormat("vector<int> x = {1, 1, 1, 1,\n"
                "                 1, 1, 1, 1, //\n"
@@ -6028,10 +6032,12 @@ TEST_F(FormatTest, ObjCDictLiterals) {
   verifyFormat("@{}");
   verifyFormat("@{@\"one\" : @1}");
   verifyFormat("return @{@\"one\" : @1;");
-  verifyFormat("@{@\"one\" : @1, }");
+  verifyFormat("@{@\"one\" : @1}");
 
   verifyFormat("@{@\"one\" : @{@2 : @1}}");
-  verifyFormat("@{@\"one\" : @{@2 : @1}, }");
+  verifyFormat("@{\n"
+               "  @\"one\" : @{@2 : @1},\n"
+               "}");
 
   verifyFormat("@{1 > 2 ? @\"one\" : @\"two\" : 1 > 2 ? @1 : @2}");
   verifyFormat("[self setDict:@{}");
-- 
2.40.0