[clang-format] Remove special handling of comments after brace/paren #71672

HazardyKnusperkeks · 2023-11-08T12:35:57Z

The code did not match the documentation about Cpp11BracedListStyle. Changed handling of comments after opening braces, which are supposedly function call like to behave exactly like their parenthesis counter part.

llvmbot · 2023-11-08T12:36:16Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-format

Author: Björn Schäpers (HazardyKnusperkeks)

Changes

Fixes http://llvm.org/PR55487

The code did not match the documentation about Cpp11BracedListStyle. Changed handling of comments after opening braces, which are supposedly function call like to behave exactly like their parenthesis counter part.

Full diff: https://github.com/llvm/llvm-project/pull/71672.diff

4 Files Affected:

(modified) clang/lib/Format/ContinuationIndenter.cpp (+3-1)
(modified) clang/lib/Format/TokenAnnotator.cpp (+3-5)
(modified) clang/unittests/Format/FormatTest.cpp (+11-13)
(modified) clang/unittests/Format/FormatTestComments.cpp (+23-6)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 3a829cdedb77fc7..1d76dbe39b00eae 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -802,7 +802,9 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
       Previous.isNot(TT_ObjCMethodExpr) && Previous.isNot(TT_RequiresClause) &&
       !(Current.MacroParent && Previous.MacroParent) &&
       (Current.isNot(TT_LineComment) ||
-       Previous.isOneOf(BK_BracedInit, TT_VerilogMultiLineListLParen))) {
+       (Previous.is(BK_BracedInit) &&
+        (!Previous.Previous || Previous.Previous->isNot(tok::identifier))) ||
+       Previous.is(TT_VerilogMultiLineListLParen))) {
     CurrentState.Indent = State.Column + Spaces;
     CurrentState.IsAligned = true;
   }
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 729e7e370bf62ea..9691d879735d3aa 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -3510,12 +3510,10 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) const {
   while (Current) {
     const FormatToken *Prev = Current->Previous;
     if (Current->is(TT_LineComment)) {
-      if (Prev->is(BK_BracedInit) && Prev->opensScope()) {
+      /*if (Prev->is(BK_BracedInit) && Prev->opensScope()) {
         Current->SpacesRequiredBefore =
-            (Style.Cpp11BracedListStyle && !Style.SpacesInParensOptions.Other)
-                ? 0
-                : 1;
-      } else if (Prev->is(TT_VerilogMultiLineListLParen)) {
+            Style.SpacesInParensOptions.Other ? 1 : 0;
+      } else */if (Prev->is(TT_VerilogMultiLineListLParen)) {
         Current->SpacesRequiredBefore = 0;
       } else {
         Current->SpacesRequiredBefore = Style.SpacesBeforeTrailingComments;
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 80903e7630c8073..e47c27c6b728c80 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -13500,20 +13500,18 @@ TEST_F(FormatTest, LayoutCxx11BraceInitializers) {
                "                                CDDDP83848_RBR_REGISTER};",
                NoBinPacking);
 
-  // FIXME: The alignment of these trailing comments might be bad. Then again,
-  // this might be utterly useless in real code.
   verifyFormat("Constructor::Constructor()\n"
-               "    : some_value{         //\n"
-               "                 aaaaaaa, //\n"
-               "                 bbbbbbb} {}");
+               "    : some_value{  //\n"
+               "          aaaaaaa, //\n"
+               "          bbbbbbb} {}");
 
   // In braced lists, the first comment is always assumed to belong to the
   // first element. Thus, it can be moved to the next or previous line as
   // appropriate.
-  verifyFormat("function({// First element:\n"
-               "          1,\n"
-               "          // Second element:\n"
-               "          2});",
+  verifyFormat("function({ // First element:\n"
+               "           1,\n"
+               "           // Second element:\n"
+               "           2});",
                "function({\n"
                "    // First element:\n"
                "    1,\n"
@@ -13582,9 +13580,9 @@ TEST_F(FormatTest, LayoutCxx11BraceInitializers) {
   verifyFormat(
       "someFunction(OtherParam,\n"
       "             BracedList{ // comment 1 (Forcing interesting break)\n"
-      "                         param1, param2,\n"
-      "                         // comment 2\n"
-      "                         param3, param4 });",
+      "                 param1, param2,\n"
+      "                 // comment 2\n"
+      "                 param3, param4 });",
       ExtraSpaces);
   verifyFormat(
       "std::this_thread::sleep_for(\n"
@@ -13635,7 +13633,7 @@ TEST_F(FormatTest, LayoutCxx11BraceInitializers) {
   verifyFormat("vector< int > x{ 1, 2, 3, 4 };", SpaceBetweenBraces);
   verifyFormat("f( {}, { {}, {} }, MyMap[ { k, v } ] );", SpaceBetweenBraces);
   verifyFormat("vector< int > x{ // comment 1\n"
-               "                 1, 2, 3, 4 };",
+               "    1, 2, 3, 4 };",
                SpaceBetweenBraces);
   SpaceBetweenBraces.ColumnLimit = 20;
   verifyFormat("vector< int > x{\n"
diff --git a/clang/unittests/Format/FormatTestComments.cpp b/clang/unittests/Format/FormatTestComments.cpp
index 967ffa32db79c75..d971744a108b531 100644
--- a/clang/unittests/Format/FormatTestComments.cpp
+++ b/clang/unittests/Format/FormatTestComments.cpp
@@ -1376,12 +1376,12 @@ TEST_F(FormatTestComments, CommentsInStaticInitializers) {
   verifyFormat("S s = {{a, b, c},  // Group #1\n"
                "       {d, e, f},  // Group #2\n"
                "       {g, h, i}}; // Group #3");
-  verifyFormat("S s = {{// Group #1\n"
-               "        a, b, c},\n"
-               "       {// Group #2\n"
-               "        d, e, f},\n"
-               "       {// Group #3\n"
-               "        g, h, i}};");
+  verifyFormat("S s = {{ // Group #1\n"
+               "         a, b, c},\n"
+               "       { // Group #2\n"
+               "         d, e, f},\n"
+               "       { // Group #3\n"
+               "         g, h, i}};");
 
   EXPECT_EQ("S s = {\n"
             "    // Some comment\n"
@@ -4576,6 +4576,23 @@ TEST_F(FormatTestComments, SplitCommentIntroducers) {
                    getLLVMStyleWithColumns(10)));
 }
 
+TEST_F(FormatTestComments, LineCommentsOnStartOfFunctionCall) {
+  verifyFormat("T foo( // Comment\n"
+               "    arg);");
+
+  verifyFormat("T bar{ // Comment\n"
+               "    arg};");
+
+  verifyFormat("T baz({ // Comment\n"
+               "        arg});");
+
+  verifyFormat("func( // Comment\n"
+               "    arg);");
+
+  verifyFormat("func({ // Comment\n"
+               "       arg});");
+}
+
 } // end namespace
 } // namespace test
 } // end namespace format

github-actions · 2023-11-08T12:38:09Z

✅ With the latest revision this PR passed the C/C++ code formatter.

HazardyKnusperkeks · 2023-11-10T11:24:17Z

Updated implementation and tests for Cpp1BracedListSyle set to false.

clang/lib/Format/ContinuationIndenter.cpp

clang/unittests/Format/FormatTestComments.cpp

clang/lib/Format/ContinuationIndenter.cpp

HazardyKnusperkeks · 2025-09-29T20:54:18Z

Currently containing the content of #161021, I will update once that's merged. But that should not hinder the review.

owenca

Now I just realized that we should add an option for the new behavior (except questionable test cases). It seems that 5a61139 only affects the formatting for Cpp11BracedListStyle: true, so we probably can change that option to an enum:

Style1 (same as true before)

SomeFunction({// Comment 1
              "first entry",
              // Comment 2
              "second entry"});

Style2 (space between { and the leading comment)

SomeFunction({ // Comment 1
               "first entry",
               // Comment 2
               "second entry"});

or

SomeFunction({ // Comment 1
    "first entry",
    // Comment 2
    "second entry"});

Style3 (same as false before)

SomeFunction({ // Comment 1
               "first entry",
               // Comment 2
               "second entry" });

@mydeveloperday WDYT?

clang/lib/Format/ContinuationIndenter.cpp

sstwcw · 2025-10-06T21:23:43Z

clang/unittests/Format/FormatTestComments.cpp

-               "       {// Group #3\n"
-               "        g, h, i}};");
+  verifyFormat("S s = {{ // Group #1\n"
+               "         a, b, c},\n"


I don't see why this line should have the extra space added. The patch removes special handling of the comment on the previous line. If the previous line is not a comment, this line will not have the extra space.

If the comment is for what comes before it like discussed in the bug report, then this line does not have to be aligned to the comment.

Oh by the way, why did this patch take so long?

It handles {} just the same as (), as a function call, and as @owenca pointed out: "If there is no name, a zero-length name is assumed."

It took so long, because things happen and I did not fine any time to actually try to work on this stuff. This is not an issue which happens in my code.

HazardyKnusperkeks · 2025-10-08T21:57:01Z

Not completely done, I'll have to remove the space and revert test changes. Just pushing for comments, especially the name. @owenca any ideas?

HazardyKnusperkeks · 2025-10-09T20:38:03Z

Now everything left is the name, maybe an adapted commit message and a review.

clang/include/clang/Format/Format.h

clang/unittests/Format/ConfigParseTest.cpp

clang/unittests/Format/FormatTestComments.cpp

owenca · 2025-10-13T05:32:40Z

Is #89956 relevant?

Fixes http://llvm.org/PR55487 (llvm#55487) The code did not match the documentation about Cpp11BracedListStyle. Changed handling of comments after opening braces, which are supposedly function call like to behave exactly like their parenthesis counter part.

owenca · 2025-10-18T07:03:36Z

Interestingly enough, the bug reported by the author of #55487 was already fixed somehow without this patch. (See #55487 (comment).) However, the code snippet in #55487 (comment) remains to be addressed.

owenca

There are a couple of places in the documentation that mention Cpp11BracedListStyle being true, which should be updated (probably to AlignFirstComment).

owenca · 2025-10-18T07:52:34Z

clang/unittests/Format/ConfigParseTest.cpp

  CHECK_PARSE("SeparateDefinitionBlocks: Never", SeparateDefinitionBlocks,
              FormatStyle::SDS_Never);
+
+  Style.Cpp11BracedListStyle = FormatStyle::BLS_FunctionCall;


You don't need this line.

HazardyKnusperkeks added the clang-format label Nov 8, 2023

HazardyKnusperkeks self-assigned this Nov 8, 2023

HazardyKnusperkeks force-pushed the space-comment branch from 4548aa1 to aeec6f1 Compare November 10, 2023 11:23

HazardyKnusperkeks requested review from mydeveloperday, owenca and rymiel November 10, 2023 11:23

owenca reviewed Nov 11, 2023

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xgupta mentioned this pull request Nov 27, 2023

[Code Coverage] Add a tool to check test coverage of a patch #71841

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HazardyKnusperkeks force-pushed the space-comment branch from aeec6f1 to 8f6e5bc Compare September 24, 2025 21:11

HazardyKnusperkeks requested a review from owenca September 27, 2025 18:31

owenca reviewed Sep 27, 2025

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HazardyKnusperkeks force-pushed the space-comment branch from 8f6e5bc to d7f7fb6 Compare September 29, 2025 20:52

HazardyKnusperkeks force-pushed the space-comment branch from d7f7fb6 to fccdc52 Compare October 4, 2025 23:01

HazardyKnusperkeks requested review from owenca and sstwcw October 4, 2025 23:01

owenca reviewed Oct 5, 2025

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HazardyKnusperkeks force-pushed the space-comment branch from fccdc52 to e743114 Compare October 8, 2025 21:55

HazardyKnusperkeks force-pushed the space-comment branch from e743114 to 331de65 Compare October 9, 2025 20:37

llvmbot added the clang Clang issues not falling into any other category label Oct 9, 2025

HazardyKnusperkeks requested a review from owenca October 9, 2025 20:38

HazardyKnusperkeks force-pushed the space-comment branch 2 times, most recently from 580f0e6 to f6de80f Compare October 10, 2025 21:56

owenca reviewed Oct 12, 2025

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HazardyKnusperkeks force-pushed the space-comment branch from f6de80f to 44b07c8 Compare October 17, 2025 20:03

owenca approved these changes Oct 18, 2025

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[clang-format] Remove special handling of comments after brace/paren #71672

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