Exclude options are confusing

[tsondergaard]

Exclude options are confusing

[latk]

Yes, these options are confusing. But changing how they behave would confuse even more people :/

The --gcov-exclude-directories option has guide-level documentation here: https://gcovr.com/en/6.0/guide/filters.html#speeding-up-coverage-data-search

You have correctly understood that this option affects what gcda files are detected.

However, this option uses the same filtering system as other filter/exclude options. That is, the value is a regex matched against a path. It is not matched just against the directory name.

The regex mcopidl would match a path mcopidl (in the current directory), but not the path mcop/mcopidl: the regex starts matching at the beginning of the path (relative to the current working directory).

If you want to exclude any directory mcopidl, you would have to use the regex (.+/)?mcopidl$. I'm sorry, I know this is awful, but at least it works consistently across filtering options.

If you know the directory's path (relative to your current working directory), you could use the regex mcop/mcopidl$ instead.

Other remarks on your gcovr invocation:

• The -j option has unclear impact on performance. It really depends on the layout of your build directories.
• You can combine the --xml and -o some-path.xml options to --cobertura some-path.xml
• If you have many exclusion patterns, consider using a config file. Note that the regexes in a config file match paths relative to that file, not relative to gcovr's working directory or root.
• Trailing .* is unnecessary in exclusion patterns. The regex is only anchored at the start, but not at the end.
• You might find the file-level --gcov-exclude easier to use than the directory-level --exclude-directories. The latter is useful mostly for steering gcovr away from searching large uninteresting directories within the search paths.

[tsondergaard]

@latk I really appreciate your help and your work on gcovr. Using (.+/)?mcopidl$ did the job. Thanks for the additional helpful suggestions!