Allow extensions to disable cop obsoletions

[dvandersluis]

Noticed this change made to rubocop-rails. There needs to be a way for an extension to disable an obsoletion (ie. rubocop-rails should not have Rails/* raise an error)

extracted:
  Rails/*: ~

Follows #9143.

---

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• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
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• Commit message starts with [Fix #issue-number] (if the related issue exists).
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• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
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[dvandersluis]

/cc @koic

[koic]

Thank you for catching up!

I tried applying the following to RuboCop Rails.

% git diff
diff --git a/Gemfile b/Gemfile
index 103582220..7daa29aee 100644
--- a/Gemfile
+++ b/Gemfile
diff --git a/Gemfile b/Gemfile
index 103582220..7daa29aee 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ gemspec
 gem 'bump', require: false
 gem 'rake'
 gem 'rspec'
-gem 'rubocop', github: 'rubocop-hq/rubocop'
+gem 'rubocop', github: 'dvandersluis/rubocop', branch: 'obsoletion-disable'
 gem 'rubocop-performance', '~> 1.9.0'
 gem 'rubocop-rspec', '~> 1.29.0'
 gem 'simplecov'
diff --git a/config/default.yml b/config/default.yml
index 7d2fe4fd5..17e7a9374 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -1,5 +1,8 @@
 # Common configuration.

+extracted:
+  Rails/*: ~
+
 inherit_mode:
   merge:
     - Exclude
diff --git a/spec/project_spec.rb b/spec/project_spec.rb
index e53a18da6..f0e2b10bd 100644
--- a/spec/project_spec.rb
+++ b/spec/project_spec.rb
@@ -4,10 +4,6 @@ RSpec.describe 'RuboCop Rails Project', type: :feature do
   describe 'default configuration file' do
     subject(:config) { RuboCop::ConfigLoader.load_file('config/default.yml') }

-    before do
-      allow_any_instance_of(RuboCop::Config).to receive(:loaded_features).and_return('rubocop-rails') # rubocop:disable RSpec/AnyInstance
-    end

But the following test failed.

% bundle exec rspec spec/project_spec.rb
(snip)

Failures:

  1) RuboCop Rails Project default configuration file sorts configuration keys alphabetically
     Failure/Error: subject(:config) { RuboCop::ConfigLoader.load_file('config/default.yml') }

     RuboCop::ValidationError:
       `Rails` cops have been extracted to the `rubocop-rails` gem.
       (obsolete configuration found in config/default.yml, please update it)
     # ./spec/project_spec.rb:5:in `block (3 levels) in <top (required)>'
     # ./spec/project_spec.rb:13:in `block (3 levels) in <top (required)>'
     # ./spec/project_spec.rb:43:in `block (3 levels) in <top (required)>'
(snip)

Am I using it incorrectly?

[dvandersluis]

Yeah sorry @koic, I should have explained better. In #9143 I added a way for extensions to define their own obsoletion file. You need to create a yaml file somewhere and then call RuboCop::ConfigObsoletion.files << path_to_file. That should solve it but let me know if something's not working.

[koic]

Ah, I get it!  Perfect! I will be introducing that to RuboCop Performance and RuboCop Rails after this PR change will be released (Because they need to adjust the supported version of the core). Thank you for the kindness explanation!