Handle tasklist update failed in app component

app/assets/javascripts/issue_show/components/app.vue

@@ -213,6 +213,14 @@ export default {
       return undefined;
     },
 
+    updateStoreState() {
+      this.service.getData()
+        .then(res => res.data)
+        .then(data => {
+          this.store.updateState(data);
+        });
+    },
+
     openForm() {
       if (!this.showForm) {
         this.showForm = true;
@@ -327,6 +335,7 @@ export default {
         :issuable-type="issuableType"
         :update-url="updateEndpoint"
         :lock-version="state.lock_version"
+        @taskListUpdateFailed="updateStoreState"
       />
       <edited-component
         v-if="hasUpdated"

app/assets/javascripts/issue_show/components/description.vue

@@ -89,8 +89,10 @@ export default {
       }
     },
 
-    taskListUpdateError(data) {
-      createFlash(data.errors[0]);
+    taskListUpdateError({ errors, data }) {
+      createFlash('Someone edited this issue at the same time you did and we updated the issue description.');
+
+      this.$emit('taskListUpdateFailed');
     },
 
     updateTaskStatusText() {