Add conversation starter for disabling rubocop rule inline to danger

- added guidance and context suggestions.

danger/plugins/rubocop.rb

+# frozen_string_literal: true
+
+require_relative '../../tooling/danger/rubocop_inline_disable_suggestion'
+
+module Danger
+  class Rubocop < ::Danger::Plugin
+    # Put the helper code somewhere it can be tested
+    def add_suggestions_for(filename)
+      Tooling::Danger::RubocopInlineDisableSuggestion.new(filename, context: self).suggest
+    end
+  end
+end

danger/rubocop/Dangerfile

+# frozen_string_literal: true
+
+helper.all_changed_files.each do |filename|
+  rubocop.add_suggestions_for(filename)
+end

spec/tooling/danger/rubocop_inline_disable_suggestion_spec.rb

+# frozen_string_literal: true
+
+require 'gitlab/dangerfiles/spec_helper'
+
+require_relative '../../../tooling/danger/rubocop_inline_disable_suggestion'
+require_relative '../../../tooling/danger/project_helper'
+
+RSpec.describe Tooling::Danger::RubocopInlineDisableSuggestion, feature_category: :tooling do
+  include_context "with dangerfile"
+
+  let(:fake_danger) { DangerSpecHelper.fake_danger }
+  let(:fake_project_helper) { instance_double('Tooling::Danger::ProjectHelper') }
+  let(:filename) { 'spec/foo_spec.rb' }
+
+  let(:template) do
+    <<~SUGGESTION_MARKDOWN.chomp
+
+    Consider removing this inline disabling and adhering to the rubocop rule.
+    If that isn't possible, please provide context as a reply for reviewers.
+    See [rubocop best practices](https://docs.gitlab.com/ee/development/rubocop_development_guide.html).
+
+    ----
+
+    [Improve this message](https://gitlab.com/gitlab-org/gitlab/-/blob/master/tooling/danger/rubocop_inline_disable_suggestion.rb)
+    or [have feedback](https://gitlab.com/gitlab-org/gitlab/-/issues/428157)?
+    SUGGESTION_MARKDOWN
+  end
+
+  let(:file_lines) do
+    <<~RUBY.split("\n")
+      def validate_credit_card?(project)
+        !current_user.has_required_credit_card_to_enable_shared_runners?(project)
+        return true if Gitlab.com? # rubocop:disable Some/Cop
+      end
+
+      def show_buy_pipeline_minutes?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+
+      def show_pipeline_minutes_notification_dot?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+        return false if notification_dot_acknowledged?
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+
+      def show_dot?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+        return false if notification_dot_acknowledged?
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+
+      def show_other_dot?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop: disable Gitlab/AvoidGitlabInstanceChecks
+        return false if notification_dot_acknowledged?
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+
+      def show_my_dot?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop:todo Gitlab/AvoidGitlabInstanceChecks
+        return false if notification_dot_acknowledged?
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+
+      def show_my_other_dot?(project, namespace)
+        return false unless ::Gitlab.com? # rubocop: todo Gitlab/AvoidGitlabInstanceChecks
+        return false if notification_dot_acknowledged?
+
+        show_out_of_pipeline_minutes_notification?(project, namespace)
+      end
+    RUBY
+  end
+
+  let(:changed_lines) do
+    <<~DIFF.split("\n")
+      +  return true if Gitlab.com? # rubocop:disable Some/Cop
+      +end
+      +  return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+      +  return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+      +  return false unless ::Gitlab.com? # rubocop:disable Gitlab/AvoidGitlabInstanceChecks
+      +  return false unless ::Gitlab.com? # rubocop: disable Gitlab/AvoidGitlabInstanceChecks
+      +  return false unless ::Gitlab.com? # rubocop:todo Gitlab/AvoidGitlabInstanceChecks
+      +  return false unless ::Gitlab.com? # rubocop: todo Gitlab/AvoidGitlabInstanceChecks
+    DIFF
+  end
+
+  subject(:rubocop) { fake_danger.new(helper: fake_helper) }
+
+  before do
+    allow(rubocop).to receive(:project_helper).and_return(fake_project_helper)
+    allow(rubocop.helper).to receive(:changed_lines).with(filename).and_return(changed_lines)
+    allow(rubocop.project_helper).to receive(:file_lines).and_return(file_lines)
+
+    rubocop.define_singleton_method(:add_suggestions_for) do |filename|
+      Tooling::Danger::RubocopInlineDisableSuggestion.new(filename, context: self).suggest
+    end
+  end
+
+  it 'adds comments at the correct lines', :aggregate_failures do
+    [3, 7, 13, 20, 27, 34, 41].each do |line_number|
+      expect(rubocop).to receive(:markdown).with(template, file: filename, line: line_number)
+    end
+
+    rubocop.add_suggestions_for(filename)
+  end
+end

tooling/danger/rubocop_inline_disable_suggestion.rb

+# frozen_string_literal: true
+
+require_relative 'suggestion'
+
+module Tooling
+  module Danger
+    class RubocopInlineDisableSuggestion < Suggestion
+      MATCH = /^\+.*#\s*rubocop\s*:\s*(?:disable|todo)\s+/
+      REPLACEMENT = nil
+
+      SUGGESTION = <<~MESSAGE_MARKDOWN
+        Consider removing this inline disabling and adhering to the rubocop rule.
+        If that isn't possible, please provide context as a reply for reviewers.
+        See [rubocop best practices](https://docs.gitlab.com/ee/development/rubocop_development_guide.html).
+
+        ----
+
+        [Improve this message](https://gitlab.com/gitlab-org/gitlab/-/blob/master/tooling/danger/rubocop_inline_disable_suggestion.rb)
+        or [have feedback](https://gitlab.com/gitlab-org/gitlab/-/issues/428157)?
+      MESSAGE_MARKDOWN
+    end
+  end
+end