Enable logging when recursive webhook detected

Remove the `webhook_recursion_detection` feature flag to enable logging
when recursive webhooks are detected.

https://gitlab.com/gitlab-org/gitlab/-/issues/349845
https://gitlab.com/gitlab-org/gitlab/-/issues/329743

Changelog: added

config/feature_flags/development/webhook_recursion_detection.yml

----
-name: webhook_recursion_detection
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/75821
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/349845
-milestone: '14.7'
-type: development
-group: group::integrations
-default_enabled: false

lib/gitlab/web_hooks/recursion_detection.rb

@@ -37,8 +37,6 @@ module Gitlab
         # Adds the webhook ID to a cache (see `#cache_key_for_hook` for
         # details of the cache).
         def register!(hook)
-          return if disabled?(hook)
-
           cache_key = cache_key_for_hook(hook)
 
           ::Gitlab::Redis::SharedState.with do |redis|
@@ -53,8 +51,6 @@ module Gitlab
         # number of IDs in the cache exceeds the limit (see
         # `#cache_key_for_hook` for details of the cache).
         def block?(hook)
-          return false if disabled?(hook)
-
           # If a request UUID has not been set then we know the request was not
           # made by a webhook, and no recursion is possible.
           return false unless UUID.instance.request_uuid
@@ -80,10 +76,6 @@ module Gitlab
 
         private
 
-        def disabled?(hook)
-          Feature.disabled?(:webhook_recursion_detection, hook.parent)
-        end
-
         # Returns a cache key scoped to a UUID.
         #
         # The particular UUID will be either:

spec/lib/gitlab/web_hooks/recursion_detection_spec.rb

@@ -128,16 +128,6 @@ RSpec.describe Gitlab::WebHooks::RecursionDetection, :clean_gitlab_redis_shared_
         end
       end
     end
-
-    it 'does not store anything if the feature flag is disabled' do
-      stub_feature_flags(webhook_recursion_detection: false)
-
-      described_class.register!(web_hook)
-
-      ::Gitlab::Redis::SharedState.with do |redis|
-        expect(redis.exists(cache_key(web_hook))).to eq(false)
-      end
-    end
   end
 
   describe 'block?' do
@@ -167,12 +157,6 @@ RSpec.describe Gitlab::WebHooks::RecursionDetection, :clean_gitlab_redis_shared_
         is_expected.to eq(true)
       end
 
-      it 'returns false if the feature flag is disabled' do
-        stub_feature_flags(webhook_recursion_detection: false)
-
-        is_expected.to eq(false)
-      end
-
       context 'when the request UUID changes again' do
         before do
           uuid_class.instance.request_uuid = SecureRandom.uuid
@@ -199,12 +183,6 @@ RSpec.describe Gitlab::WebHooks::RecursionDetection, :clean_gitlab_redis_shared_
         is_expected.to eq(true)
       end
 
-      it 'returns false if the feature flag is disabled' do
-        stub_feature_flags(webhook_recursion_detection: false)
-
-        is_expected.to eq(false)
-      end
-
       context 'when the request UUID changes again' do
         before do
           uuid_class.instance.request_uuid = SecureRandom.uuid

spec/requests/recursive_webhook_detection_spec.rb

@@ -45,20 +45,6 @@ RSpec.describe 'Recursive webhook detection', :sidekiq_inline, :clean_gitlab_red
         .once
     end
 
-    shared_examples 'when the feature flag is disabled' do
-      it 'executes and logs no errors' do
-        stub_feature_flags(webhook_recursion_detection: false)
-        stub_requests
-
-        expect(Gitlab::AuthLogger).not_to receive(:error)
-
-        trigger_web_hooks
-
-        expect(WebMock).to have_requested(:post, stubbed_hostname(project_hook.url)).once
-        expect(WebMock).to have_requested(:post, stubbed_hostname(system_hook.url)).once
-      end
-    end
-
     context 'when one of the webhooks is recursive' do
       before do
         # Recreate the necessary state for the previous request to be
@@ -87,8 +73,6 @@ RSpec.describe 'Recursive webhook detection', :sidekiq_inline, :clean_gitlab_red
         expect(WebMock).to have_requested(:post, stubbed_hostname(project_hook.url)).once
         expect(WebMock).to have_requested(:post, stubbed_hostname(system_hook.url)).once
       end
-
-      include_examples 'when the feature flag is disabled'
     end
 
     context 'when the count limit has been reached' do
@@ -134,8 +118,6 @@ RSpec.describe 'Recursive webhook detection', :sidekiq_inline, :clean_gitlab_red
         expect(WebMock).to have_requested(:post, stubbed_hostname(system_hook.url)).once
       end
     end
-
-    include_examples 'when the feature flag is disabled'
   end
 
   context 'when the recursive webhook detection header is absent' do