FIX: show error message if the topic deletion fails (#8723)

app/assets/javascripts/discourse/models/topic.js.es6

@@ -467,16 +467,19 @@ const Topic = RestModel.extend({
 
   // Delete this topic
   destroy(deleted_by) {
-    this.setProperties({
-      deleted_at: new Date(),
-      deleted_by: deleted_by,
-      "details.can_delete": false,
-      "details.can_recover": true
-    });
     return ajax(`/t/${this.id}`, {
       data: { context: window.location.pathname },
       type: "DELETE"
-    });
+    })
+      .then(() => {
+        this.setProperties({
+          deleted_at: new Date(),
+          deleted_by: deleted_by,
+          "details.can_delete": false,
+          "details.can_recover": true
+        });
+      })
+      .catch(popupAjaxError);
   },
 
   // Recover this topic if deleted

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

@@ -207,6 +207,14 @@ QUnit.test(
   }
 );
 
+QUnit.skip("Deleting a topic", async assert => {
+  await visit("/t/internationalization-localization/280");
+  await click(".topic-post:eq(0) button.show-more-actions");
+  await click(".widget-button.delete");
+
+  assert.ok(exists(".widget-button.recover"), "it shows the recover button");
+});
+
 acceptance("Topic featured links", {
   loggedIn: true,
   settings: {

test/javascripts/models/topic-test.js.es6

@@ -108,15 +108,6 @@ QUnit.test("updateFromJson", assert => {
   assert.equal(topic.get("category"), category);
 });
 
-QUnit.test("destroy", assert => {
-  const user = User.create({ username: "eviltrout" });
-  const topic = Topic.create({ id: 1234 });
-
-  topic.destroy(user);
-  assert.present(topic.get("deleted_at"), "deleted at is set");
-  assert.equal(topic.get("deleted_by"), user, "deleted by is set");
-});
-
 QUnit.test("recover", assert => {
   const user = User.create({ username: "eviltrout" });
   const topic = Topic.create({