clang-format only formats comments correctly when column width is set explicitly

[llvmbot]

Bugzilla Link	39380
Version	unspecified
OS	Linux
Reporter	LLVM Bugzilla Contributor

Extended Description

After a few hours trying around I finally found the following issue with clang-format-6.0 on Ubuntu using a configuration file derived from dumping WebKit style:

If the configuration file contains the original line

ColumnLimit: 0
then a C++ code comment like
//some text
will not be fixed by adding an extra space after '//'

Changing the configuration file to

ColumnLimit: 120
a C++ code comment like
//some text
is converted to
// some text

This means that identical .clang-format config files lead to different output depending on the input not only for line wrapping (which I would accept), but also to the completely unrelated comments.

BTW: IMHO adding spaces to a comment should be an extra option anyway

[JOE1994]

With clang trunk as of 3/21/2025 (at 052a4b54a75364f13ea5001bba00691da4d8c239),
clang-format does the same job for when ColumnLimit: 0 & when ColumnLimit: 120.
The issue described in the ticket seems to be resolved now (no longer reproducible).