Update MultipleDatabase cop to allow some methods

Add for specified methods to be allowed on ActiveRecord::Base in the
Database/MultipleDatabases cop. Also add `no_touching` as the first
method in the allowlist.

.rubocop_todo/database/multiple_databases.yml

@@ -18,10 +18,8 @@ Database/MultipleDatabases:
   - lib/gitlab/database/migrations/observers/query_log.rb
   - lib/gitlab/database/partitioning_migration_helpers/backfill_partitioned_table.rb
   - lib/gitlab/database.rb
-  - lib/gitlab/gitlab_import/importer.rb
   - lib/gitlab/health_checks/db_check.rb
   - lib/gitlab/import_export/group/relation_tree_restorer.rb
-  - lib/gitlab/legacy_github_import/importer.rb
   - lib/gitlab/seeder.rb
   - spec/db/schema_spec.rb
   - spec/initializers/database_config_spec.rb

rubocop/cop/database/multiple_databases.rb

@@ -17,6 +17,10 @@ module RuboCop
           https://docs.gitlab.com/ee/development/database/transaction_guidelines.html
         EOF
 
+        ALLOWED_METHODS = %i[
+          no_touching
+        ].freeze
+
         def_node_matcher :active_record_base_method_is_used?, <<~PATTERN
         (send (const (const nil? :ActiveRecord) :Base) $_)
         PATTERN
@@ -24,8 +28,17 @@ module RuboCop
         def on_send(node)
           return unless active_record_base_method_is_used?(node)
 
+          active_record_base_method = node.children[1]
+          return if method_is_allowed?(active_record_base_method)
+
           add_offense(node, location: :expression, message: AR_BASE_MESSAGE)
         end
+
+        private
+
+        def method_is_allowed?(method_name)
+          ALLOWED_METHODS.include?(method_name.to_sym)
+        end
       end
     end
   end

spec/rubocop/cop/database/multiple_databases_spec.rb

@@ -12,4 +12,14 @@ RSpec.describe RuboCop::Cop::Database::MultipleDatabases do
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not use methods from ActiveRecord::Base, [...]
     SOURCE
   end
+
+  described_class::ALLOWED_METHODS.each do |method_name|
+    it "does not flag use of ActiveRecord::Base.#{method_name}" do
+      expect_no_offenses(<<~SOURCE)
+        ActiveRecord::Base.#{method_name} do
+          Project.save
+        end
+      SOURCE
+    end
+  end
 end