--disable-pending-cops causes rubocop false positives #782

Overcommit 0.59.0 added --disable-pending-cops to the default rubocop flags. This causes rubocop to now report violations in some cases, where before this change it would not.

In my project, I have explicitly configured rubocop via .rubocop.yml to enable all pending cops, like this:

AllCops:
  NewCops: enable

When overcommit 0.59.0 executes rubocop, it specifies --disable-pending-cops, which contradicts and overrides my NewCops: enable setting. This causes a violation to be reported like this:

Warnings on modified lines:
/home/circleci/project/test/system/article_integration_test.rb:4:54: W: [Correctable] Lint/RedundantCopDisableDirective: Unnecessary disabling of `Minitest/MultipleAssertions`.

This is because Minitest/MultipleAssertions is a "pending" cop that I have explicitly opted into using NewCops: enable. The code in question has this comment:

# rubocop:disable Minitest/MultipleAssertions

When overcommit runs rubocop --disable-pending-cops, rubocop now treats the Minitest/MultipleAssertions cop is if it doesn't exist, thus this error:

Unnecessary disabling of `Minitest/MultipleAssertions`

My workaround is to customize my .overcommit.yml to redefine the rubocop flags, like this (i.e. omitting --disable-pending-cops):

RuboCop:
  enabled: true
  flags: ["--format=emacs", "--force-exclusion", "--display-cop-names"]

In my opinion, overcommit should not be passing flags to rubocop that change its behavior. It should limit itself to passing flags that are purely related to command line output, like --format=emacs. If someone wants pending cops to be skipped, they should say so in .rubocop.yml like this:

AllCops:
  NewCops: disable

Why is overcommit overriding this setting?