Pass tasklist lock version

receive data on when there is a conflict

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

@@ -326,6 +326,7 @@ export default {
         :task-status="state.taskStatus"
         :issuable-type="issuableType"
         :update-url="updateEndpoint"
+        :lock-version="state.lock_version"
       />
       <edited-component
         v-if="hasUpdated"

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

@@ -35,6 +35,10 @@ export default {
       required: false,
       default: null,
     },
+    lockVersion: {
+      type: Number,
+      required: false,
+    },
   },
   data() {
     return {
@@ -67,8 +71,10 @@ export default {
         new TaskList({
           dataType: this.issuableType,
           fieldName: 'description',
+          lockVersion: this.lockVersion,
           selector: '.detail-page-description',
           onSuccess: this.taskListUpdateSuccess.bind(this),
+          onError: this.taskListUpdateError.bind(this),
         });
       }
     },
@@ -82,6 +88,10 @@ export default {
       }
     },
+    taskListUpdateError(data) {
+      // stub for error handling
+    },
+
     updateTaskStatusText() {
       const taskRegexMatches = this.taskStatus.match(/(\d+) of ((?!0)\d+)/);
       const $issuableHeader = $('.issuable-meta');

app/assets/javascripts/task_list.js

@@ -8,8 +8,9 @@ export default class TaskList {
     this.selector = options.selector;
     this.dataType = options.dataType;
     this.fieldName = options.fieldName;
+    this.lockVersion = options.lockVersion;
     this.onSuccess = options.onSuccess || (() => {});
-    this.onError = function showFlash(e) {
+    this.onError = options.onError || function showFlash(e) {
       let errorMessages = '';
       if (e.response.data && typeof e.response.data === 'object') {
@@ -43,6 +44,7 @@ export default class TaskList {
     const patchData = {};
     patchData[this.dataType] = {
       [this.fieldName]: $target.val(),
+      ['lock_version']: this.lockVersion,
     };
     return axios

app/controllers/concerns/issuable_actions.rb

@@ -162,10 +162,13 @@ module IssuableActions
       end
       format.json do
+        # We want to pass back the latest valid data, so reload the model
+        @issuable.reload
         render json: {
           errors: [
             "Someone edited this #{issuable.human_class_name} at the same time you did. Please refresh your browser and make sure your changes will not unintentionally remove theirs."
-          ]
+          ],
+          data: serializer.represent(@issuable)
         }, status: :conflict
       end
     end