Merge branch '56970-fix-mr-stuck-loading-on-error' into 'master'

Resolve "Merge request page loses state"

See merge request gitlab-org/gitlab-ce!25988

app/assets/javascripts/lib/utils/simple_poll.js

-export default (fn, interval = 2000, timeout = 60000) => {
+export default (fn, { interval = 2000, timeout = 60000 } = {}) => {
   const startTime = Date.now();
   return new Promise((resolve, reject) => {
     const stop = arg => (arg instanceof Error ? reject(arg) : resolve(arg));
     const next = () => {
-      if (Date.now() - startTime < timeout) {
+      if (timeout === 0 || Date.now() - startTime < timeout) {
         setTimeout(fn.bind(null, next, stop), interval);
       } else {
         reject(new Error('SIMPLE_POLL_TIMEOUT'));

app/assets/javascripts/vue_merge_request_widget/components/states/ready_to_merge.vue

@@ -165,9 +165,12 @@ export default {
         });
     },
     initiateMergePolling() {
-      simplePoll((continuePolling, stopPolling) => {
-        this.handleMergePolling(continuePolling, stopPolling);
-      });
+      simplePoll(
+        (continuePolling, stopPolling) => {
+          this.handleMergePolling(continuePolling, stopPolling);
+        },
+        { timeout: 0 },
+      );
     },
     handleMergePolling(continuePolling, stopPolling) {
       this.service
@@ -198,6 +201,7 @@ export default {
         })
         .catch(() => {
           new Flash(__('Something went wrong while merging this merge request. Please try again.')); // eslint-disable-line
+          stopPolling();
         });
     },
     initiateRemoveSourceBranchPolling() {

changelogs/unreleased/56970-fix-mr-stuck-loading-on-error.yml

+---
+title: Disable timeout on merge request merging poll
+merge_request: 25988
+author:
+type: fixed

spec/javascripts/vue_mr_widget/components/states/mr_widget_ready_to_merge_spec.js

@@ -377,11 +377,29 @@ describe('ReadyToMerge', () => {
     });
     describe('initiateMergePolling', () => {
+      beforeEach(() => {
+        jasmine.clock().install();
+      });
+
+      afterEach(() => {
+        jasmine.clock().uninstall();
+      });
+
       it('should call simplePoll', () => {
         const simplePoll = spyOnDependency(ReadyToMerge, 'simplePoll');
         vm.initiateMergePolling();
-        expect(simplePoll).toHaveBeenCalled();
+        expect(simplePoll).toHaveBeenCalledWith(jasmine.any(Function), { timeout: 0 });
+      });
+
+      it('should call handleMergePolling', () => {
+        spyOn(vm, 'handleMergePolling');
+
+        vm.initiateMergePolling();
+
+        jasmine.clock().tick(2000);
+
+        expect(vm.handleMergePolling).toHaveBeenCalled();
       });
     });