use relation_path instead of destroy_relation_path

ee/app/services/epic_issues/list_service.rb

@@ -21,9 +21,5 @@ module EpicIssues
     def reference(issue)
       issue.to_reference(full: true)
     end
-
-    def to_hash(issue)
-      super.merge(relation_path: relation_path(issue))
-    end
   end
 end

ee/app/services/issuable_links/list_service.rb

@@ -26,7 +26,8 @@ module IssuableLinks
         title: issue.title,
         state: issue.state,
         reference: reference(issue),
-        path: project_issue_path(issue.project, issue.iid)
+        path: project_issue_path(issue.project, issue.iid),
+        relation_path: relation_path(issue)
       }
     end
   end

ee/app/services/issue_links/list_service.rb

 module IssueLinks
   class ListService < IssuableLinks::ListService
+    include Gitlab::Utils::StrongMemoize
+
     private
 
     def issues
       issuable.related_issues(current_user, preload: { project: :namespace })
     end
 
-    def destroy_relation_path(issue)
-      current_project = issuable.project
-
+    def relation_path(issue)
       # Make sure the user can admin both the current issue AND the
       # referenced issue projects in order to return the removal link.
-      if can_destroy_issue_link_on_current_project?(current_project) && can_destroy_issue_link?(issue.project)
+      if can_admin_issue_link_on_current_project? && can_admin_issue_link?(issue.project)
         project_issue_link_path(current_project, issuable.iid, issue.issue_link_id)
       end
     end
 
-    def can_destroy_issue_link_on_current_project?(current_project)
-      return @can_destroy_on_current_project if defined?(@can_destroy_on_current_project)
-
-      @can_destroy_on_current_project = can_destroy_issue_link?(current_project)
+    def can_admin_issue_link_on_current_project?
+      strong_memoize(:can_admin_on_current_project) do
+        can_admin_issue_link?(current_project)
+      end
     end
 
-    def can_destroy_issue_link?(project)
+    def can_admin_issue_link?(project)
       Ability.allowed?(current_user, :admin_issue_link, project)
     end
 
-    def to_hash(issue)
-      super.merge(destroy_relation_path: destroy_relation_path(issue))
+    def current_project
+      issuable.project
     end
   end
 end

spec/ee/spec/services/issue_links/list_service_spec.rb

@@ -57,21 +57,21 @@ describe IssueLinks::ListService do
                                            state: issue_b.state,
                                            reference: issue_b.to_reference(project),
                                            path: "/#{project.full_path}/issues/#{issue_b.iid}",
-                                           destroy_relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_a.id}"))
+                                           relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_a.id}"))
 
         expect(subject).to include(include(id: issue_c.id,
                                            title: issue_c.title,
                                            state: issue_c.state,
                                            reference: issue_c.to_reference(project),
                                            path: "/#{project.full_path}/issues/#{issue_c.iid}",
-                                           destroy_relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_b.id}"))
+                                           relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_b.id}"))
 
         expect(subject).to include(include(id: issue_d.id,
                                            title: issue_d.title,
                                            state: issue_d.state,
                                            reference: issue_d.to_reference(project),
                                            path: "/#{project.full_path}/issues/#{issue_d.iid}",
-                                           destroy_relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_c.id}"))
+                                           relation_path: "/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link_c.id}"))
       end
     end
 
@@ -164,7 +164,7 @@ describe IssueLinks::ListService do
         it 'returns no destroy relation path' do
           target_project.add_developer(user)
 
-          expect(subject.first[:destroy_relation_path]).to be_nil
+          expect(subject.first[:relation_path]).to be_nil
         end
       end
 
@@ -176,7 +176,7 @@ describe IssueLinks::ListService do
         it 'returns no destroy relation path' do
           target_project.add_guest(user)
 
-          expect(subject.first[:destroy_relation_path]).to be_nil
+          expect(subject.first[:relation_path]).to be_nil
         end
       end
 
@@ -184,7 +184,7 @@ describe IssueLinks::ListService do
         let(:referenced_issue) { create :issue, project: project }
 
         it 'returns related issue destroy relation path' do
-          expect(subject.first[:destroy_relation_path])
+          expect(subject.first[:relation_path])
             .to eq("/#{project.full_path}/issues/#{issue.iid}/links/#{issue_link.id}")
         end
       end