Merge pull request #1445 from koic/fix_an_error_when_using_target_rai…

…ls_version

[Fix #1442] Fix an incorrect behavior when using `AllCops: TargetRailsVersion`

changelog/fix_an_error_when_using_target_rails_version.md

@@ -0,0 +1 @@
+* [#1442](https://github.com/rubocop/rubocop-rails/issues/1442): Fix an incorrect behavior when using `AllCops: TargetRailsVersion`. ([@koic][])

lib/rubocop/rails/plugin.rb

@@ -24,8 +24,25 @@ def rules(_context)
 
         ConfigObsoletion.files << project_root.join('config', 'obsoletion.yml')
 
+        # FIXME: This is a dirty hack relying on a private constant to prevent
+        # "Warning: AllCops does not support TargetRailsVersion parameter".
+        # It should be updated to a better design in the future.
+        without_warnings do
+          ConfigValidator.const_set(:COMMON_PARAMS, ConfigValidator::COMMON_PARAMS.dup << 'TargetRailsVersion')
+        end
+
         LintRoller::Rules.new(type: :path, config_format: :rubocop, value: project_root.join('config', 'default.yml'))
       end
+
+      private
+
+      def without_warnings
+        original_verbose = $VERBOSE
+        $VERBOSE = nil
+        yield
+      ensure
+        $VERBOSE = original_verbose
+      end
     end
   end
 end