[clang-format] Don't move comments if AlignTrailingComments: Kind: Leave

[mairacanal]

Summary

For comments that start after a new line, currently, the comments are
being indented. This happens because the OriginalWhitespaceRange
considers newlines on the range. Therefore, when AlignTrailingComments:
Kind: Leave, deduct the number of newlines before the token to calculate
the number of spaces for trailing comments.

Fixes llvm#59203

[HazardyKnusperkeks]

Can you please add a test with more than one newline?

clang/unittests/Format/FormatTestComments.cpp

3065–3075

Makes it clearer what is happening here.

[mairacanal]

In D139029#3961372, @HazardyKnusperkeks wrote:

Can you please add a test with more than one newline?

Hi @HazardyKnusperkeks! Thanks for the feedback. It looks like Changes[i].NewlinesBefore values 1 even if I put multiple lines before the comment. Do you have any input on what could be causing this? From my point of view, it looks like the extra new lines are being removed before alignTrailingComments and then Changes[i].NewlinesBefore = 1, but I'm not really sure how to solve it.

[HazardyKnusperkeks]

In D139029#3961438, @mairacanal wrote:

In D139029#3961372, @HazardyKnusperkeks wrote:

Can you please add a test with more than one newline?

Hi @HazardyKnusperkeks! Thanks for the feedback. It looks like Changes[i].NewlinesBefore values 1 even if I put multiple lines before the comment. Do you have any input on what could be causing this? From my point of view, it looks like the extra new lines are being removed before alignTrailingComments and then Changes[i].NewlinesBefore = 1, but I'm not really sure how to solve it.

Try setting MaxEmptyLinesToKeep to a higher number.

[HazardyKnusperkeks]

In D139029#3961444, @HazardyKnusperkeks wrote:

In D139029#3961438, @mairacanal wrote:

In D139029#3961372, @HazardyKnusperkeks wrote:

Can you please add a test with more than one newline?

Hi @HazardyKnusperkeks! Thanks for the feedback. It looks like Changes[i].NewlinesBefore values 1 even if I put multiple lines before the comment. Do you have any input on what could be causing this? From my point of view, it looks like the extra new lines are being removed before alignTrailingComments and then Changes[i].NewlinesBefore = 1, but I'm not really sure how to solve it.

Try setting MaxEmptyLinesToKeep to a higher number.

We can also use two additional test cases, with MaxEmptyLinesToKeep and without, always good to see that it works.

[mairacanal]

This comment was removed by mairacanal.

[mairacanal]

• Instead of using Changes[i].NewlinesBefore use Changes[i].Tok->NewlinesBefore: this allows the correct behavior for test cases with multiple blank lines
• Create test cases of multiple blank lines
• Separate \n\n on test cases

[HazardyKnusperkeks]

Thanks, nice work.

Do you need someone to push it for you? In that case we need a name and an email address for the commit.

[mairacanal]

In D139029#3961512, @HazardyKnusperkeks wrote:

Thanks, nice work.

Do you need someone to push it for you? In that case we need a name and an email address for the commit.

Yes, I would need someone to push for me. My name and address are Maíra Canal <[e-mail]>. Thanks for the help!

[yusuke-kadowaki]

@mairacanal
Thank you for the catch!

clang/unittests/Format/FormatTestComments.cpp

3101

This should probably be reset after this testcase to avoid side effects for other test cases.

[mairacanal]

Reset Style.MaxEmptyLinesToKeep after the test case to avoid side effects for other test cases.

[owenpan]

Please mark comments as done if you have addressed them.

clang/unittests/Format/FormatTestComments.cpp

3071

3078

3087

3096

3108

3116

[mairacanal]

Remove \n from the end of the test cases

clang/lib/Format/WhitespaceManager.cpp

if (Changes[i].StartOfBlockComment)
       continue;
     Newlines += Changes[i].NewlinesBefore;
     if (!Changes[i].IsTrailingComment)
       continue;
 
     if (Style.AlignTrailingComments.Kind == FormatStyle::TCAS_Leave) {
       auto OriginalSpaces =
           Changes[i].OriginalWhitespaceRange.getEnd().getRawEncoding() -
-          Changes[i].OriginalWhitespaceRange.getBegin().getRawEncoding();
+          Changes[i].OriginalWhitespaceRange.getBegin().getRawEncoding() -
+          Changes[i].Tok->NewlinesBefore;
       unsigned RestoredLineLength = Changes[i].StartOfTokenColumn +
                                     Changes[i].TokenLength + OriginalSpaces;
       // If leaving comments makes the line exceed the column limit, give up to
       // leave the comments.
       if (RestoredLineLength >= Style.ColumnLimit && Style.ColumnLimit != 0)
         break;
       Changes[i].Spaces = OriginalSpaces;
       continue;

clang/unittests/Format/FormatTestComments.cpp

EXPECT_EQ("int a;   // do not touch\n"
             "int c; // comment\n"
             "int d;// comment\n",
             format("int a;   // do not touch\n"
                    "int b;  // any comments\n"
                    "int c; // comment\n"
                    "int d;// comment\n",
                    Style));
 
+  EXPECT_EQ("// do not touch\n"
+            "int a;  // any comments\n"
+            "\n"
+            "   // comment\n"
+            "// comment\n"
+            "\n"
+            "// comment",
+            format("// do not touch\n"
+                   "int a;  // any comments\n"
+                   "\n"
+                   "   // comment\n"
+                   "// comment\n"
+                   "\n"
+                   "// comment",
+                   Style));
+
+  EXPECT_EQ("// do not touch\n"
+            "int a;  // any comments\n"
+            "\n"
+            "   // comment\n"
+            "// comment\n"
+            "\n"
+            "// comment",
+            format("// do not touch\n"
+                   "int a;  // any comments\n"
+                   "\n"
+                   "\n"
+                   "   // comment\n"
+                   "// comment\n"
+                   "\n"
+                   "\n"
+                   "// comment",
+                   Style));
+
+  // Allow to keep 2 empty lines
+  Style.MaxEmptyLinesToKeep = 2;
+  EXPECT_EQ("// do not touch\n"
+            "int a;  // any comments\n"
+            "\n"
+            "\n"
+            "   // comment\n"
+            "// comment\n"
+            "\n"
+            "// comment",
+            format("// do not touch\n"
+                   "int a;  // any comments\n"
+                   "\n"
+                   "\n"
+                   "   // comment\n"
+                   "// comment\n"
+                   "\n"
+                   "// comment",
+                   Style));
+  Style.MaxEmptyLinesToKeep = 1;
+
   // Just format comments normally when leaving exceeds the column limit
   Style.ColumnLimit = 35;
   EXPECT_EQ("int foo = 12345; // comment\n"
             "int bar =\n"
             "    1234; // This is a very long\n"
             "          // comment which is\n"
             "          // wrapped arround.\n",
             format("int foo = 12345; // comment\n"