Respect DisabledByDefault for custom cops

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ### Bug fixes
 
+* [#7013](https://github.com/rubocop-hq/rubocop/pull/7013): Respect DisabledByDefault for custom cops. ([@XrXr][])
 * [#7043](https://github.com/rubocop-hq/rubocop/issues/7043): Prevent RDoc error when installing RuboCop 0.69.0 on Ubuntu. ([@koic][])
 
 ## 0.69.0 (2019-05-13)

lib/rubocop/config.rb

@@ -720,7 +720,7 @@ def enable_cop?(qualified_cop_name, cop_options)
         end
       end
 
-      cop_options.fetch('Enabled', true)
+      cop_options.fetch('Enabled') { !for_all_cops['DisabledByDefault'] }
     end
 
     def smart_loaded_path

spec/rubocop/config_spec.rb

@@ -730,6 +730,40 @@ def cop_enabled(cop_class)
         expect(cop_enabled(cop_class)).to be true
       end
     end
+
+    context 'when configuration has no mention of a cop' do
+      let(:hash) do
+        {}
+      end
+
+      it 'enables the cop that is not mentioned' do
+        expect(cop_enabled('VeryCustomDepartment/CustomCop')).to be true
+      end
+
+      context 'when all cops are disabled by default' do
+        let(:hash) do
+          {
+            'AllCops' => { 'DisabledByDefault' => true }
+          }
+        end
+
+        it 'disables the cop that is not mentioned' do
+          expect(cop_enabled('VeryCustomDepartment/CustomCop')).to be false
+        end
+      end
+
+      context 'when all cops are explicitly enabled by default' do
+        let(:hash) do
+          {
+            'AllCops' => { 'EnabledByDefault' => true }
+          }
+        end
+
+        it 'enables the cop that is not mentioned' do
+          expect(cop_enabled('VeryCustomDepartment/CustomCop')).to be true
+        end
+      end
+    end
   end
 
   describe '#target_rails_version' do