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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Trailing comments after endif adds macro continuation"
href="https://bugs.llvm.org/show_bug.cgi?id=46964">46964</a>
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<th>Summary</th>
<td>Trailing comments after endif adds macro continuation
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>10.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Formatter
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>geoffrey.carlton@activision.com
</td>
</tr>
<tr>
<th>CC</th>
<td>djasper@google.com, klimek@google.com, llvm-bugs@lists.llvm.org
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<pre>Created <span class=""><a href="attachment.cgi?id=23809" name="attach_23809" title="Input to be formatted with llvm and ColumnLimit 0">attachment 23809</a> <a href="attachment.cgi?id=23809&action=edit" title="Input to be formatted with llvm and ColumnLimit 0">[details]</a></span>
Input to be formatted with llvm and ColumnLimit 0
When an #endif or #else has a trailing comment, and a comment follows on the
next line, clang-format can add an inappropriate macro continuation '\\' at the
end of the first comment.
Minimum repro is attached. Input file is attached, but is in full:
"#if A()\n#endif // #if A()\n\t\t\t// hello\n"
Output becomes:
"#if A()\n#endif // #if A() \\\n // hello\n"
Reproduces in clang 10.0.0 with -style="{BasedOnStyle: llvm, ColumnLimit: 0}".
Also reproduces in latest code built from github.
The code is related to ContinuationIndenter::addTokenOnNewLine where it is
adding whitespace with ContinuePPDirective set. That causes the comment to be
joined with the macro continuation character.
A partial workaround is before that call to replaceWhitespace:
if (State.Line->First->is(tok::hash) && Current.is(tok::comment) &&
State.Line->First->Next != nullptr) {
if (isIfdefType(State.Line->First->Next)) {
// Don't count this trailing comment part of a PP directive or it will
// unnecessarily escape the end with '\' If we happen to have a another
// comment on the next line.
ContinuePPDirective = false;
// An additional problem is later parts of clang-format can shift
around
// the following comment, causing the output not to be stable.
Current.Finalized = true;
}
}
Where isIfdefType is checking for ifdef/elif/else/endif. That's good enough
for a quick fix but isn't the real solution to the problem.</pre>
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