Set cached MRWidget SHA after rebase

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

@@ -72,7 +72,7 @@ export default {
               Flash('Something went wrong. Please try again.');
             }
 
-            eventHub.$emit('MRWidgetUpdateRequested');
+            eventHub.$emit('MRWidgetRebaseSuccess');
             stopPolling();
           }
         })

app/assets/javascripts/vue_merge_request_widget/mr_widget_options.vue

@@ -156,13 +156,13 @@ export default {
       };
       return new MRWidgetService(endpoints);
     },
-    checkStatus(cb) {
+    checkStatus(cb, isRebased) {
       return this.service
         .checkStatus()
         .then(res => res.data)
         .then(data => {
           this.handleNotification(data);
-          this.mr.setData(data);
+          this.mr.setData(data, isRebased);
           this.setFaviconHelper();
 
           if (cb) {
@@ -264,6 +264,10 @@ export default {
         this.checkStatus(cb);
       });
 
+      eventHub.$on('MRWidgetRebaseSuccess', cb => {
+        this.checkStatus(cb, true);
+      });
+
       // `params` should be an Array contains a Boolean, like `[true]`
       // Passing parameter as Boolean didn't work.
       eventHub.$on('SetBranchRemoveFlag', params => {

app/assets/javascripts/vue_merge_request_widget/stores/get_state_key.js

@@ -19,7 +19,7 @@ export default function deviseState(data) {
     return stateKey.unresolvedDiscussions;
   } else if (this.isPipelineBlocked) {
     return stateKey.pipelineBlocked;
-  } else if (this.hasSHAChanged) {
+  } else if (this.isSHAMismatch) {
     return stateKey.shaMismatch;
   } else if (this.mergeWhenPipelineSucceeds) {
     return this.mergeError ? stateKey.autoMergeFailed : stateKey.mergeWhenPipelineSucceeds;

app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js

@@ -11,7 +11,11 @@ export default class MergeRequestStore {
     this.setData(data);
   }
 
-  setData(data) {
+  setData(data, isRebased) {
+    if (isRebased) {
+      this.sha = data.diff_head_sha;
+    }
+
     const currentUser = data.current_user;
     const pipelineStatus = data.pipeline ? data.pipeline.details.status : null;
 
@@ -84,7 +88,7 @@ export default class MergeRequestStore {
     this.canMerge = !!data.merge_path;
     this.canCreateIssue = currentUser.can_create_issue || false;
     this.canCancelAutomaticMerge = !!data.cancel_merge_when_pipeline_succeeds_path;
-    this.hasSHAChanged = this.sha !== data.diff_head_sha;
+    this.isSHAMismatch = this.sha !== data.diff_head_sha;
     this.canBeMerged = data.can_be_merged || false;
     this.isMergeAllowed = data.mergeable || false;
     this.mergeOngoing = data.merge_ongoing;

changelogs/unreleased/47052-merge-button-does-not-appear-after-rebase-ing.yml

+---
+title: Allow merge after rebase without page refresh on FF repositories
+merge_request: 23572
+author:
+type: fixed

ee/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js

@@ -27,11 +27,11 @@ export default class MergeRequestStore extends CEMergeRequestStore {
     this.licenseManagement = data.license_management;
   }
 
-  setData(data) {
+  setData(data, isRebased) {
     this.initGeo(data);
     this.initApprovals(data);
 
-    super.setData(data);
+    super.setData(data, isRebased);
   }
 
   initGeo(data) {

spec/javascripts/vue_mr_widget/components/mr_widget_rebase_spec.js

@@ -114,7 +114,7 @@ describe('Merge request widget rebase component', () => {
         // Wait for the eventHub to be called
         .then(vm.$nextTick())
         .then(() => {
-          expect(eventHub.$emit).toHaveBeenCalledWith('MRWidgetUpdateRequested');
+          expect(eventHub.$emit).toHaveBeenCalledWith('MRWidgetRebaseSuccess');
         })
         .then(done)
         .catch(done.fail);

spec/javascripts/vue_mr_widget/stores/get_state_key_spec.js

@@ -35,7 +35,7 @@ describe('getStateKey', () => {
 
     expect(bound()).toEqual('mergeWhenPipelineSucceeds');
 
-    context.hasSHAChanged = true;
+    context.isSHAMismatch = true;
 
     expect(bound()).toEqual('shaMismatch');
 

spec/javascripts/vue_mr_widget/stores/mr_widget_store_spec.js

@@ -10,16 +10,23 @@ describe('MergeRequestStore', () => {
   });
 
   describe('setData', () => {
-    it('should set hasSHAChanged when the diff SHA changes', () => {
+    it('should set isSHAMismatch when the diff SHA changes', () => {
       store.setData({ ...mockData, diff_head_sha: 'a-different-string' });
 
-      expect(store.hasSHAChanged).toBe(true);
+      expect(store.isSHAMismatch).toBe(true);
     });
 
-    it('should not set hasSHAChanged when other data changes', () => {
+    it('should not set isSHAMismatch when other data changes', () => {
       store.setData({ ...mockData, work_in_progress: !mockData.work_in_progress });
 
-      expect(store.hasSHAChanged).toBe(false);
+      expect(store.isSHAMismatch).toBe(false);
+    });
+
+    it('should update cached sha after rebasing', () => {
+      store.setData({ ...mockData, diff_head_sha: 'abc123' }, true);
+
+      expect(store.isSHAMismatch).toBe(false);
+      expect(store.sha).toBe('abc123');
     });
 
     describe('isPipelinePassing', () => {