Remove EE-specific code from Mentionable

app/models/concerns/mentionable.rb

@@ -10,6 +10,8 @@
 module Mentionable
   extend ActiveSupport::Concern
 
+  prepend EE::Mentionable
+
   class_methods do
     # Indicate which attributes of the Mentionable to search for GFM references.
     def attr_mentionable(attr, options = {})
@@ -86,12 +88,11 @@ module Mentionable
     return [] unless matches_cross_reference_regex?
 
     refs = all_references(current_user)
-    refs = (refs.issues + refs.merge_requests + refs.commits + refs.epics)
 
     # We're using this method instead of Array diffing because that requires
     # both of the object's `hash` values to be the same, which may not be the
     # case for otherwise identical Commit objects.
-    refs.reject { |ref| ref == local_reference }
+    extracted_mentionables(refs).reject { |ref| ref == local_reference }
   end
 
   # Uses regex to quickly determine if mentionables might be referenced
@@ -134,6 +135,10 @@ module Mentionable
 
   private
 
+  def extracted_mentionables(refs)
+    refs.issues + refs.merge_requests + refs.commits
+  end
+
   # Returns a Hash of changed mentionable fields
   #
   # Preference is given to the `changes` Hash, but falls back to

app/models/concerns/mentionable/reference_regexes.rb

@@ -2,17 +2,24 @@
 
 module Mentionable
   module ReferenceRegexes
+    prepend EE::Mentionable::ReferenceRegexes
+
     def self.reference_pattern(link_patterns, issue_pattern)
       Regexp.union(link_patterns,
                    issue_pattern,
-                   Epic.reference_pattern,
-                   Commit.reference_pattern,
-                   MergeRequest.reference_pattern)
+                   *other_patterns)
+    end
+
+    def self.other_patterns
+      [
+        Commit.reference_pattern,
+        MergeRequest.reference_pattern
+      ]
     end
 
     DEFAULT_PATTERN = begin
       issue_pattern = Issue.reference_pattern
-      link_patterns = Regexp.union([Issue, Commit, MergeRequest, Epic].map(&:link_reference_pattern))
+      link_patterns = Regexp.union([Issue, Commit, MergeRequest, Epic].map(&:link_reference_pattern).compact)
       reference_pattern(link_patterns, issue_pattern)
     end
 

app/models/epic.rb

@@ -5,6 +5,10 @@
 class Epic < ActiveRecord::Base
   prepend EE::Epic
 
+  def self.link_reference_pattern
+    nil
+  end
+
   def self.reference_prefix
     '&'
   end

ee/app/models/concerns/ee/mentionable.rb

+# frozen_string_literal: true
+
+module EE
+  module Mentionable
+    extend ::Gitlab::Utils::Override
+
+    private
+
+    override :extracted_mentionables
+    def extracted_mentionables(refs)
+      super + refs.epics
+    end
+  end
+end

ee/app/models/concerns/ee/mentionable/reference_regexes.rb

+# frozen_string_literal: true
+
+module EE
+  module Mentionable
+    module ReferenceRegexes
+      extend ActiveSupport::Concern
+
+      class_methods do
+        extend ::Gitlab::Utils::Override
+
+        override :other_patterns
+        def other_patterns
+          [
+            ::Epic.reference_pattern,
+            *super
+          ]
+        end
+      end
+    end
+  end
+end