Fixed potential issue with 2 ci status polling events happening

app/assets/javascripts/merge_request_widget.js.coffee

@@ -10,6 +10,7 @@ class @MergeRequestWidget
     $('#modal_merge_info').modal(show: false)
     @firstCICheck = true
     @readyForCICheck = false
+    @cancel = false
     clearInterval @fetchBuildStatusInterval
 
     @clearEventListeners()
@@ -21,10 +22,16 @@ class @MergeRequestWidget
   clearEventListeners: ->
     $(document).off 'page:change.merge_request'
 
+  cancelPolling: ->
+    @cancel = true
+
   addEventListeners: ->
+    allowedPages = ['show', 'commits', 'builds', 'changes']
     $(document).on 'page:change.merge_request', =>
-      if $('body').data('page') isnt 'projects:merge_requests:show'
+      page = $('body').data('page').split(':').last()
+      if allowedPages.indexOf(page) < 0
         clearInterval @fetchBuildStatusInterval
+        @cancelPolling()
         @clearEventListeners()
 
   mergeInProgress: (deleteSourceBranch = false)->
@@ -67,6 +74,7 @@ class @MergeRequestWidget
     $('.ci-widget-fetching').show()
 
     $.getJSON @opts.ci_status_url, (data) =>
+      return if @cancel
       @readyForCICheck = true
 
       if data.status is ''

app/views/projects/merge_requests/widget/_show.html.haml

@@ -13,7 +13,7 @@
     check_enable: #{@merge_request.unchecked? ? "true" : "false"},
     ci_status_url: "#{ci_status_namespace_project_merge_request_path(@project.namespace, @project, @merge_request)}",
     gitlab_icon: "#{asset_path 'gitlab_logo.png'}",
-    ci_status: "",
+    ci_status: "#{@merge_request.ci_commit ? @merge_request.ci_commit.status : ''}",
     ci_message: {
       normal: "Build {{status}} for \"{{title}}\"",
       preparing: "{{status}} build for \"{{title}}\""
@@ -26,4 +26,10 @@
     builds_path: "#{builds_namespace_project_merge_request_path(@project.namespace, @project, @merge_request)}"
   };
 
+  if (typeof merge_request_widget !== 'undefined') {
+    clearInterval(merge_request_widget.fetchBuildStatusInterval);
+    merge_request_widget.cancelPolling();
+    merge_request_widget.clearEventListeners();
+  }
+
   merge_request_widget = new MergeRequestWidget(opts);