Remove feature flag milestone_reference_pattern

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/336268

New reference search mechanism shows better results than the previous
version. The feature flag can be removed.

Changelog: changed

app/models/milestone.rb

@@ -61,18 +61,10 @@ class Milestone < ApplicationRecord
   end
 
   def self.reference_pattern
-    if Feature.enabled?(:milestone_reference_pattern, default_enabled: :yaml)
-      new_reference_pattern
-    else
-      old_reference_pattern
-    end
-  end
-
-  def self.new_reference_pattern
     # NOTE: The iid pattern only matches when all characters on the expression
     # are digits, so it will match %2 but not %2.1 because that's probably a
     # milestone name and we want it to be matched as such.
-    @new_reference_pattern ||= %r{
+    @reference_pattern ||= %r{
       (#{Project.reference_pattern})?
       #{Regexp.escape(reference_prefix)}
       (?:
@@ -87,26 +79,6 @@ class Milestone < ApplicationRecord
     }x
   end
 
-  # Deprecated: https://gitlab.com/gitlab-org/gitlab/-/issues/336268
-  def self.old_reference_pattern
-    # NOTE: The iid pattern only matches when all characters on the expression
-    # are digits, so it will match %2 but not %2.1 because that's probably a
-    # milestone name and we want it to be matched as such.
-    @old_reference_pattern ||= %r{
-      (#{Project.reference_pattern})?
-      #{Regexp.escape(reference_prefix)}
-      (?:
-        (?<milestone_iid>
-          \d+(?!\S\w)\b # Integer-based milestone iid, or
-        ) |
-        (?<milestone_name>
-          [^"\s]+\b |  # String-based single-word milestone title, or
-          "[^"]+"      # String-based multi-word milestone surrounded in quotes
-        )
-      )
-    }x
-  end
-
   def self.link_reference_pattern
     @link_reference_pattern ||= super("milestones", /(?<milestone>\d+)/)
   end

config/feature_flags/development/milestone_reference_pattern.yml

----
-name: milestone_reference_pattern
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65847
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/336268
-milestone: '14.1'
-type: development
-group: group::source code
-default_enabled: false

lib/banzai/filter/references/reference_cache.rb

@@ -28,11 +28,18 @@ module Banzai
           @references_per_parent[parent_type] ||= begin
             refs = Hash.new { |hash, key| hash[key] = Set.new }
 
-            if Feature.enabled?(:milestone_reference_pattern, default_enabled: :yaml)
-              doc_search(refs)
-            else
-              node_search(nodes, refs)
+            prepare_doc_for_scan(filter.doc).to_enum(:scan, regex).each do
+              parent_path = if parent_type == :project
+                              full_project_path($~[:namespace], $~[:project])
+                            else
+                              full_group_path($~[:group])
+                            end
+
+              ident = filter.identifier($~)
+              refs[parent_path] << ident if ident
             end
+
+            refs
           end
         end
 
@@ -163,39 +170,6 @@ module Banzai
 
         delegate :project, :group, :parent, :parent_type, to: :filter
 
-        # Deprecated: https://gitlab.com/gitlab-org/gitlab/-/issues/336268
-        def node_search(nodes, refs)
-          nodes.each do |node|
-            prepare_node_for_scan(node).scan(regex) do
-              parent_path = if parent_type == :project
-                              full_project_path($~[:namespace], $~[:project])
-                            else
-                              full_group_path($~[:group])
-                            end
-
-              ident = filter.identifier($~)
-              refs[parent_path] << ident if ident
-            end
-          end
-
-          refs
-        end
-
-        def doc_search(refs)
-          prepare_doc_for_scan(filter.doc).to_enum(:scan, regex).each do
-            parent_path = if parent_type == :project
-                            full_project_path($~[:namespace], $~[:project])
-                          else
-                            full_group_path($~[:group])
-                          end
-
-            ident = filter.identifier($~)
-            refs[parent_path] << ident if ident
-          end
-
-          refs
-        end
-
         def regex
           strong_memoize(:regex) do
             [
@@ -215,13 +189,6 @@ module Banzai
           filter.requires_unescaping? ? unescape_html_entities(html) : html
         end
 
-        # Deprecated: https://gitlab.com/gitlab-org/gitlab/-/issues/336268
-        def prepare_node_for_scan(node)
-          html = node.to_html
-
-          filter.requires_unescaping? ? unescape_html_entities(html) : html
-        end
-
         def unescape_html_entities(text)
           CGI.unescapeHTML(text.to_s)
         end

spec/models/milestone_spec.rb

@@ -538,15 +538,6 @@ RSpec.describe Milestone do
 
     it { is_expected.to match('gitlab-org/gitlab-ce%123') }
     it { is_expected.to match('gitlab-org/gitlab-ce%"my-milestone"') }
-
-    context 'when milestone_reference_pattern feature flag is false' do
-      before do
-        stub_feature_flags(milestone_reference_pattern: false)
-      end
-
-      it { is_expected.to match('gitlab-org/gitlab-ce%123') }
-      it { is_expected.to match('gitlab-org/gitlab-ce%"my-milestone"') }
-    end
   end
 
   describe '.link_reference_pattern' do