Feature flag for release generation

lib/gitlab/ci/config/entry/job.rb

@@ -35,6 +35,12 @@ module Gitlab
                 message: 'key may not be used with `rules`'
               },
               if: :has_rules?
+            validates :config,
+              disallowed_keys: {
+                in: %i[release],
+                message: 'release features are not enabled'
+              },
+              unless: -> { Feature.enabled?(:ci_release_generation, default_enabled: false) }
 
             with_options allow_nil: true do
               validates :allow_failure, boolean: true

spec/lib/gitlab/ci/yaml_processor_spec.rb

@@ -1331,9 +1331,9 @@ module Gitlab
             stub_feature_flags(ci_release_generation: false)
           end
 
-          it "returns release info" do
-            expect(processor.stage_builds_attributes('release').first[:options].include?(config[:release]))
-              .to be false
+          it 'raises error' do
+            expect { processor }.to raise_error(
+              'jobs:release config release features are not enabled: release')
           end
         end
       end