Merge branch 'mr-close-btn' into 'master'

Correctly shows close button on merge requests

Closes #19403 

See merge request !5036

app/helpers/merge_requests_helper.rb

@@ -96,4 +96,8 @@ module MergeRequestsHelper
       ["#{source_path}:#{source_branch}", "#{target_path}:#{target_branch}"]
     end
   end
+
+  def merge_request_button_visibility(merge_request, closed)
+    return 'hidden' if merge_request.closed? == closed || (merge_request.merged? == closed && !merge_request.closed?)
+  end
 end

app/views/projects/merge_requests/show/_mr_title.html.haml

@@ -19,13 +19,13 @@
           Options
         .dropdown-menu.dropdown-menu-align-right.hidden-lg
           %ul
-            %li{ class: issue_button_visibility(@merge_request, true) }
+            %li{ class: merge_request_button_visibility(@merge_request, true) }
               = link_to 'Close', merge_request_path(@merge_request, merge_request: { state_event: :close }), method: :put, title: 'Close merge request'
-            %li{ class: issue_button_visibility(@merge_request, false) }
+            %li{ class: merge_request_button_visibility(@merge_request, false) }
               = link_to 'Reopen', merge_request_path(@merge_request, merge_request: {state_event: :reopen }), method: :put, class: 'reopen-mr-link', title: 'Reopen merge request'
             %li
               = link_to 'Edit', edit_namespace_project_merge_request_path(@project.namespace, @project, @merge_request), class: 'issuable-edit'
-        = link_to 'Close', merge_request_path(@merge_request, merge_request: { state_event: :close }), method: :put, class: "hidden-xs hidden-sm btn btn-grouped btn-close #{issue_button_visibility(@merge_request, true)}", title: 'Close merge request'
-        = link_to 'Reopen', merge_request_path(@merge_request, merge_request: {state_event: :reopen }), method: :put, class: "hidden-xs hidden-sm btn btn-grouped btn-reopen reopen-mr-link #{issue_button_visibility(@merge_request, false)}", title: 'Reopen merge request'
+        = link_to 'Close', merge_request_path(@merge_request, merge_request: { state_event: :close }), method: :put, class: "hidden-xs hidden-sm btn btn-grouped btn-close #{merge_request_button_visibility(@merge_request, true)}", title: 'Close merge request'
+        = link_to 'Reopen', merge_request_path(@merge_request, merge_request: {state_event: :reopen }), method: :put, class: "hidden-xs hidden-sm btn btn-grouped btn-reopen reopen-mr-link #{merge_request_button_visibility(@merge_request, false)}", title: 'Reopen merge request'
         = link_to edit_namespace_project_merge_request_path(@project.namespace, @project, @merge_request), class: "hidden-xs hidden-sm btn btn-grouped issuable-edit" do
           Edit