Fix failure when issue author is nil

app/views/projects/issues/show.html.haml

@@ -32,7 +32,8 @@
         %ul
           - if can_update_issue
             %li= link_to 'Edit', edit_project_issue_path(@project, @issue)
-          - unless current_user == @issue.author
+            / TODO: simplify condition back #36860
+          - if @issue.author && current_user != @issue.author
             %li= link_to 'Report abuse', new_abuse_report_path(user_id: @issue.author.id, ref_url: issue_url(@issue))
           - if can_update_issue
             %li= link_to 'Close issue', issue_path(@issue, issue: { state_event: :close }, format: 'json'), class: "btn-close #{issue_button_visibility(@issue, true)}", title: 'Close issue'

app/views/shared/issuable/_close_reopen_button.html.haml

@@ -9,6 +9,7 @@
             class: "hidden-xs hidden-sm btn btn-grouped btn-reopen #{issuable_button_visibility(issuable, false)}", title: "Reopen #{display_issuable_type}"
 - elsif can_update && !is_current_user
   = render 'shared/issuable/close_reopen_report_toggle', issuable: issuable
-- else
+- elsif issuable.author
+  / TODO: change back to else #36860
   = link_to 'Report abuse', new_abuse_report_path(user_id: issuable.author.id, ref_url: issuable_url(issuable)),
             class: 'hidden-xs hidden-sm btn btn-grouped btn-close-color', title: 'Report abuse'

app/views/shared/issuable/_close_reopen_report_toggle.html.haml

@@ -37,6 +37,8 @@
 
       %li.divider.droplab-item-ignore
 
+      / TODO: remove condition #36860
+      - if issuable.author
         %li.report-item{ data: { text: 'Report abuse', url: new_abuse_report_path(user_id: issuable.author.id, ref_url: issuable_url(issuable)),
                          button_class: "#{button_class} btn-close-color", toggle_class: "#{toggle_class} btn-close-color", method: '' } }
           %button.btn.btn-transparent

changelogs/unreleased/36860-deleted-user-fix.yml

+---
+title: Fix failure when issue is authored by a deleted user
+merge_request: 13807
+author:
+type: fixed

spec/features/issues/issue_detail_spec.rb

@@ -40,4 +40,18 @@ feature 'Issue Detail', :js do
       end
     end
   end
+
+  context 'when authored by a user who is later deleted' do
+    before do
+      issue.update_attribute(:author_id, nil)
+      sign_in(user)
+      visit project_issue_path(project, issue)
+    end
+
+    it 'shows the issue' do
+      page.within('.issuable-details') do
+        expect(find('h2')).to have_content(issue.title)
+      end
+    end
+  end
 end