Unexpected glob behavior when including files

[dduugg]

In the brew repo, I would like to our non-vendored .rbi files (Sorbet's "Ruby Interface" files, written in Ruby) to be covered by RuboCop. However, I just noticed that our configuration wasn't behaving as expected.

In particular, I'm seeing that this configuration:

AllCops:
  Include:
    - "**/*.rbi"

is less inclusive than this one:

AllCops:
  Include:
    - "Homebrew/**/*.rbi"

As a demonstration, this PR leads to these violations, although there are no violations on the base branch.

---

Expected behavior

**/*.rbi should be a superset of Homebrew/**/*.rbi

Actual behavior

Homebrew/**/*.rbi includes files that **/*.rbi does not (I'm not actually sure the latter is including any files)

Steps to reproduce the problem

See the config file and PR run linked above. I don't have a more minimal repro available, but could attempt one if needed.

RuboCop version

Include the output of rubocop -V or bundle exec rubocop -V if using Bundler.
If you see extension cop versions (e.g. rubocop-performance, rubocop-rspec, and others)
output by rubocop -V, include them as well. Here's an example:

1.60.2 (using Parser 3.3.0.5, rubocop-ast 1.30.0, running on ruby 3.1.4) [arm64-darwin20]
with:
    rubocop-ast (1.30.0)
    rubocop-capybara (2.20.0)
    rubocop-factory_bot (2.25.1)
    rubocop-md (1.2.2)
    rubocop-performance (1.20.2)
    rubocop-rspec (2.26.1)
    rubocop-sorbet (0.7.7)

[jonas054]

What ultimately causes this behavior is that File.fnmatch('../**/*.irb', 'Homebrew/file.irb', File::FNM_PATHNAME | File::FNM_EXTGLOB) returns false. This is a bit unexpected if you ask me, but that's how it is and we must adapt to the fact. I'll try to provide a solution.

The ../ in the pattern - in case you're wondering - comes from the fact that Library/Homebrew/.rubocop.yml inherits from ../.rubocop.yml and in configuration files that begin with .rubocop, we interpret include/exclude paths as being relative to the file itself, rather than relative to the current directory.

[dduugg]

Thank you‼️