1 files changed, 35 insertions, 8 deletions
diff --git a/app/services/issuable_links/create_service.rb b/app/services/issuable_links/create_service.rb
index 81685f81afa..802260c8fae 100644
--- a/app/services/issuable_links/create_service.rb
+++ b/app/services/issuable_links/create_service.rb
@@ -17,7 +17,7 @@ module IssuableLinks
       # otherwise create issue links for the issues which
       # are still not assigned and return success message.
       if render_conflict_error?
-        return error(issuables_assigned_message, 409)
+        return error(issuables_already_assigned_message, 409)
       end
 
       if render_not_found_error?
@@ -36,6 +36,20 @@ module IssuableLinks
       success
     end
 
+    # rubocop: disable CodeReuse/ActiveRecord
+    def relate_issuables(referenced_issuable)
+      link = link_class.find_or_initialize_by(source: issuable, target: referenced_issuable)
+
+      set_link_type(link)
+
+      if link.changed? && link.save
+        create_notes(referenced_issuable)
+      end
+
+      link
+    end
+    # rubocop: enable CodeReuse/ActiveRecord
+
     private
 
     def render_conflict_error?
@@ -96,6 +110,23 @@ module IssuableLinks
       {}
     end
 
+    def issuables_already_assigned_message
+      _('%{issuable}(s) already assigned' % { issuable: target_issuable_type.capitalize })
+    end
+
+    def issuables_not_found_message
+      _('No matching %{issuable} found. Make sure that you are adding a valid %{issuable} URL.' % { issuable: target_issuable_type })
+    end
+
+    def target_issuable_type
+      :issue
+    end
+
+    def create_notes(referenced_issuable)
+      SystemNoteService.relate_issuable(issuable, referenced_issuable, current_user)
+      SystemNoteService.relate_issuable(referenced_issuable, issuable, current_user)
+    end
+
     def linkable_issuables(objects)
       raise NotImplementedError
     end
@@ -104,16 +135,12 @@ module IssuableLinks
       raise NotImplementedError
     end
 
-    def relate_issuables(referenced_object)
+    def link_class
       raise NotImplementedError
     end
 
-    def issuables_assigned_message
-      _("Issue(s) already assigned")
-    end
-
-    def issuables_not_found_message
-      _("No matching issue found. Make sure that you are adding a valid issue URL.")
+    def set_link_type(_link)
+      # no-op
     end
   end
 end