--ignore-parent-exclusion does not work if --parallel is used

[dhinus]

The switch --ignore-parent-exclusion seems to be ignored if --parallel is also present.

---

Expected behavior

The following commands should always inspect the same number of files:

rubocop --ignore-parent-exclusion
rubocop --ignore-parent-exclusion --parallel

Actual behavior

Adding --parallel seems to disable the effect of --ignore-parent-exclusion.

Steps to reproduce the problem

.
├── .rubocop.yml
└── subdir
    ├── .rubocop.yml
    └── test.rb

Content of .rubocop.yml:

AllCops:
  Exclude:
    - "subdir/*"

Content of subdir/.rubocop.yml:

AllCops:
  Exclude:
    - "foobar"

This is the output of running Rubocop with different switches, from inside the subdir directory:

• rubocop: "0 file inspected"
• rubocop --parallel: "0 file inspected"
• rubocop --ignore-parent-exclusion: "1 file inspected"
• rubocop --ignore-parent-exclusion --parallel: "0 files inspected"

NOTE: to be fair, I'm not even sure why I need to use the --ignore-parent-exclusion flag, as I'm not specifying inherit in the config file inside subdir, so I would expect Rubocop to use that file and ignore the config file in the parent directory.

RuboCop version

Include the output of rubocop -V or bundle exec rubocop -V if using Bundler. Here's an example:

$ rubocop -V
0.80.1 (using Parser 2.7.0.2, running on ruby 2.5.1 x86_64-darwin18)

[jonas054]

NOTE: to be fair, I'm not even sure why I need to use the --ignore-parent-exclusion flag, as I'm not specifying inherit in the config file inside subdir, so I would expect Rubocop to use that file and ignore the config file in the parent directory.

That's by design. If RuboCop, when run from a subdirectory, would inspect files that are excluded when running from the project root, that would be kind of a gotcha. I'm not sure about the exact scenarios when this becomes an issue, but the behavior is not an accident.