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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Issues with formatting comments within switch statements"
href="https://bugs.llvm.org/show_bug.cgi?id=48668">48668</a>
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<th>Summary</th>
<td>Issues with formatting comments within switch statements
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>MacOS X
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Formatter
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>timwoj@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>djasper@google.com, klimek@google.com, llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>I ran into what I'm pretty sure is a bug in clang-format with handling comments
within switch statements. I initially discovered this with the Whitesmiths
mode, but it appears to happen in Allman mode as well. I tested it with the
following configuration:
Language: Cpp
Standard: c++17
BreakBeforeBraces: Whitesmiths
IndentCaseLabels: true
IndentCaseBlocks: false
IndentWidth: 4
TabWidth: 4
UseTab: AlignWithSpaces
I tested it with the following input (test case 1):
int main(int argc, char** argv)
{
switch ( value )
{
// Comment
case 0:
break;
}
}
I would expect clang-format to take that comment and align it with the the
block and the case statement, but this is what I get:
int main(int argc, char **argv)
{
switch (value)
{
// Comment
case 0:
break;
}
}
As a second test, I indented the comment to where I’d expect, such as (test
case 2):
int main(int argc, char** argv)
{
switch ( value )
{
// Comment
case 0:
break;
}
}
Running clang-format on this input, I get something completely different:
int main(int argc, char **argv)
{
switch (value)
{
// Comment
case 0:
break;
}
}
I tried to trace through the code around this a bit. Comments are complicated,
but with test case 1 it appears that Line->Level gets set to 3 during
UnwrappedLineParser::parse. This flows down to the formatter later, and it
misinterprets what the indentation should be for that line. I modified the
configuration listed above changing the BreakBeforeBraces option to Allman, but
leaving everything else the same. With that configuration it properly indents
test case 2 but not test case 1. I get the following output with that test:
int main(int argc, char **argv)
{
switch (value)
{
// Comment
case 0:
break;
}
}
That mirrors the output problem that I get from Whitesmiths. This seems to
indicate to me that it’s not something about the Whitesmiths setting itself,
but something deeper than that.</pre>
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