FIX: Endless spinner when anonymous users navigated to 404s

app/assets/javascripts/discourse/models/post-stream.js.es6

@@ -713,7 +713,7 @@ const PostStream = RestModel.extend({
     // If the result was 404 the post is not found
     if (status === 404) {
       topic.set('errorTitle', I18n.t('topic.not_found.title'));
-      topic.set('notFoundHtml', result.responseText);
+      topic.set('notFoundHtml', result.jqXHR.responseText);
       return;
     }
 

app/assets/javascripts/discourse/templates/topic.hbs

@@ -125,7 +125,7 @@
   <div class='container'>
     {{#conditional-loading-spinner condition=noErrorYet}}
       {{#if model.notFoundHtml}}
-        {{{model.notFoundHtml}}}
+        <div class='not-found'>{{{model.notFoundHtml}}}</div>
       {{else}}
         <div class="topic-error">
           <div>{{model.message}}</div>

test/javascripts/acceptance/topic-anonymous-test.js.es6

@@ -16,6 +16,14 @@ test("Enter without an id", () => {
   });
 });
 
+test("Enter a 404 topic", (assert) => {
+  visit("/t/not-found/404");
+  andThen(() => {
+    assert.ok(!exists("#topic"), "The topic was not rendered");
+    assert.ok(find(".not-found").text() === "not found", "it renders the error message");
+  });
+});
+
 test("Enter without access", (assert) => {
   visit("/t/i-dont-have-access/403");
   andThen(() => {

test/javascripts/helpers/create-pretender.js.es6

@@ -179,6 +179,10 @@ export default function() {
       return response(403, {});
     });
 
+    this.get('/t/404.json', () => {
+      return response(404, "not found");
+    });
+
     this.get('/t/500.json', () => {
       return response(502, {});
     });