Remove ci_custom_yaml_tags feature flag

Remove ci_custom_yaml_tags feature flag

changelogs/unreleased/remove-ci-custom-tags-ff-300155.yml

+---
+title: Add '!reference' YAML tag to help merge CI configurations
+merge_request: 54198
+author:
+type: added

config/feature_flags/development/ci_custom_yaml_tags.yml

----
-name: ci_custom_yaml_tags
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/52104
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/300155
-milestone: '13.9'
-type: development
-group: group::pipeline authoring
-default_enabled: false

doc/ci/yaml/README.md

@@ -4600,13 +4600,6 @@ into templates.
 ### `!reference` tags
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/266173) in GitLab 13.9.
-> - It's [deployed behind a feature flag](../../user/feature_flags.md), disabled by default.
-> - It's disabled on GitLab.com.
-> - It's not recommended for production use.
-> - To use it in GitLab self-managed instances, ask a GitLab administrator to [enable it](#enable-or-disable-reference-tags). **(FREE SELF)**
-
-WARNING:
-This feature might not be available to you. Check the **version history** note above for details.
 
 Use the `!reference` custom YAML tag to select keyword configuration from other job
 sections and reuse it in the current section. Unlike [YAML anchors](#anchors), you can
@@ -4666,25 +4659,6 @@ test-vars-2:
 You can't reuse a section that already includes a `!reference` tag. Only one level
 of nesting is supported.
 
-#### Enable or disable `!reference` tags **(FREE SELF)**
-
-The `!reference` tag is under development and not ready for production use. It is
-deployed behind a feature flag that is **disabled by default**.
-[GitLab administrators with access to the GitLab Rails console](../../administration/feature_flags.md)
-can enable it.
-
-To enable it:
-
-```ruby
-Feature.enable(:ci_custom_yaml_tags)
-```
-
-To disable it:
-
-```ruby
-Feature.disable(:ci_custom_yaml_tags)
-```
-
 ## Skip Pipeline
 
 To push a commit without triggering a pipeline, add `[ci skip]` or `[skip ci]`, using any

lib/gitlab/ci/config.rb

@@ -90,15 +90,7 @@ module Gitlab
       end
 
       def build_config(config)
-        if ::Feature.enabled?(:ci_custom_yaml_tags, @context.project, default_enabled: :yaml)
-          build_config_with_custom_tags(config)
-        else
-          build_config_without_custom_tags(config)
-        end
-      end
-
-      def build_config_with_custom_tags(config)
-        initial_config = Config::Yaml.load!(config, project: @context.project)
+        initial_config = Config::Yaml.load!(config)
         initial_config = Config::External::Processor.new(initial_config, @context).perform
         initial_config = Config::Extendable.new(initial_config).to_hash
         initial_config = Config::Yaml::Tags::Resolver.new(initial_config).to_hash
@@ -107,15 +99,6 @@ module Gitlab
         initial_config
       end
 
-      def build_config_without_custom_tags(config)
-        initial_config = Gitlab::Config::Loader::Yaml.new(config).load!
-        initial_config = Config::External::Processor.new(initial_config, @context).perform
-        initial_config = Config::Extendable.new(initial_config).to_hash
-        initial_config = Config::EdgeStagesInjector.new(initial_config).to_hash
-
-        initial_config
-      end
-
       def build_context(project:, sha:, user:, parent_pipeline:)
         Config::External::Context.new(
           project: project,

lib/gitlab/ci/config/external/file/base.rb

@@ -60,11 +60,7 @@ module Gitlab
 
             def content_hash
               strong_memoize(:content_yaml) do
-                if ::Feature.enabled?(:ci_custom_yaml_tags, context.project, default_enabled: :yaml)
-                  ::Gitlab::Ci::Config::Yaml.load!(content)
-                else
-                  Gitlab::Config::Loader::Yaml.new(content).load!
-                end
+                ::Gitlab::Ci::Config::Yaml.load!(content)
               end
             rescue Gitlab::Config::Loader::FormatError
               nil

lib/gitlab/ci/config/yaml.rb

@@ -7,7 +7,7 @@ module Gitlab
         AVAILABLE_TAGS = [Config::Yaml::Tags::Reference].freeze
 
         class << self
-          def load!(content, project: nil)
+          def load!(content)
             ensure_custom_tags
 
             Gitlab::Config::Loader::Yaml.new(content, additional_permitted_classes: AVAILABLE_TAGS).load!