Store MergeWorker JID on merge request, and clean up stuck merges

28 files changed, 193 insertions, 54 deletions

diff --git a/.flayignore b/.flayignore
index e2d0a2e50c5..b63ce4c4df0 100644
--- a/.flayignore
+++ b/.flayignore
@@ -3,4 +3,5 @@ lib/gitlab/sanitizers/svg/whitelist.rb
 lib/gitlab/diff/position_tracer.rb
 app/policies/project_policy.rb
 app/models/concerns/relative_positioning.rb
+app/workers/stuck_merge_jobs_worker.rb
 lib/gitlab/redis/*.rb
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_locked.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merging.js
index a12f418e1af..f6d1a4feeb2 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_locked.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merging.js
@@ -1,7 +1,7 @@
 import statusIcon from '../mr_widget_status_icon';
 
 export default {
-  name: 'MRWidgetLocked',
+  name: 'MRWidgetMerging',
   props: {
     mr: { type: Object, required: true },
   },
@@ -13,7 +13,7 @@ export default {
       <status-icon status="loading" />
       <div class="media-body">
         <h4>
-          This merge request is in the process of being merged, during which time it is locked and cannot be closed
+          This merge request is in the process of being merged
         </h4>
         <section class="mr-info-list">
           <p>
diff --git a/app/assets/javascripts/vue_merge_request_widget/dependencies.js b/app/assets/javascripts/vue_merge_request_widget/dependencies.js
index 546a3f625c7..49340c232c8 100644
--- a/app/assets/javascripts/vue_merge_request_widget/dependencies.js
+++ b/app/assets/javascripts/vue_merge_request_widget/dependencies.js
@@ -19,7 +19,7 @@ export { default as WidgetRelatedLinks } from './components/mr_widget_related_li
 export { default as MergedState } from './components/states/mr_widget_merged';
 export { default as FailedToMerge } from './components/states/mr_widget_failed_to_merge';
 export { default as ClosedState } from './components/states/mr_widget_closed';
-export { default as LockedState } from './components/states/mr_widget_locked';
+export { default as MergingState } from './components/states/mr_widget_merging';
 export { default as WipState } from './components/states/mr_widget_wip';
 export { default as ArchivedState } from './components/states/mr_widget_archived';
 export { default as ConflictsState } from './components/states/mr_widget_conflicts';
diff --git a/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js b/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
index 577d77f09a6..0042c48816f 100644
--- a/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
+++ b/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
@@ -8,7 +8,7 @@ import {
   WidgetRelatedLinks,
   MergedState,
   ClosedState,
-  LockedState,
+  MergingState,
   WipState,
   ArchivedState,
   ConflictsState,
@@ -212,7 +212,7 @@ export default {
     'mr-widget-related-links': WidgetRelatedLinks,
     'mr-widget-merged': MergedState,
     'mr-widget-closed': ClosedState,
-    'mr-widget-locked': LockedState,
+    'mr-widget-merging': MergingState,
     'mr-widget-failed-to-merge': FailedToMerge,
     'mr-widget-wip': WipState,
     'mr-widget-archived': ArchivedState,
diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
index fddafb0ddfa..fbea764b739 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js
@@ -73,6 +73,7 @@ export default class MergeRequestStore {
     this.canCancelAutomaticMerge = !!data.cancel_merge_when_pipeline_succeeds_path;
     this.hasSHAChanged = this.sha !== data.diff_head_sha;
     this.canBeMerged = data.can_be_merged || false;
+    this.mergeOngoing = data.merge_ongoing;
 
     // Cherry-pick and Revert actions related
     this.canCherryPickInCurrentMR = currentUser.can_cherry_pick_on_current_merge_request || false;
@@ -94,6 +95,11 @@ export default class MergeRequestStore {
   }
 
   setState(data) {
+    if (this.mergeOngoing) {
+      this.state = 'merging';
+      return;
+    }
+
     if (this.isOpen) {
       this.state = getStateKey.call(this, data);
     } else {
@@ -104,9 +110,6 @@ export default class MergeRequestStore {
         case 'closed':
           this.state = 'closed';
           break;
-        case 'locked':
-          this.state = 'locked';
-          break;
         default:
           this.state = null;
       }
diff --git a/app/assets/javascripts/vue_merge_request_widget/stores/state_maps.js b/app/assets/javascripts/vue_merge_request_widget/stores/state_maps.js
index 605dd3a1ff4..9074a064a6d 100644
--- a/app/assets/javascripts/vue_merge_request_widget/stores/state_maps.js
+++ b/app/assets/javascripts/vue_merge_request_widget/stores/state_maps.js
@@ -1,7 +1,7 @@
 const stateToComponentMap = {
   merged: 'mr-widget-merged',
   closed: 'mr-widget-closed',
-  locked: 'mr-widget-locked',
+  merging: 'mr-widget-merging',
   conflicts: 'mr-widget-conflicts',
   missingBranch: 'mr-widget-missing-branch',
   workInProgress: 'mr-widget-wip',
@@ -20,7 +20,7 @@ const stateToComponentMap = {
 };
 
 const statesToShowHelpWidget = [
-  'locked',
+  'merging',
   'conflicts',
   'workInProgress',
   'readyToMerge',
diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index d361e661d0e..4de814d0ca8 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -67,11 +67,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
         @noteable = @merge_request
         @commits_count = @merge_request.commits_count
 
-        if @merge_request.locked_long_ago?
-          @merge_request.unlock_mr
-          @merge_request.close
-        end
-
         labels
 
         set_pipeline_variables
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 8ca850b6d96..e0c779b4fbc 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -61,16 +61,6 @@ class MergeRequest < ActiveRecord::Base
       transition locked: :opened
     end
 
-    after_transition any => :locked do |merge_request, transition|
-      merge_request.locked_at = Time.now
-      merge_request.save
-    end
-
-    after_transition locked: (any - :locked) do |merge_request, transition|
-      merge_request.locked_at = nil
-      merge_request.save
-    end
-
     state :opened
     state :closed
     state :merged
@@ -392,6 +382,12 @@ class MergeRequest < ActiveRecord::Base
                'Source project is not a fork of the target project'
   end
 
+  def merge_ongoing?
+    return false unless merge_jid
+
+    Gitlab::SidekiqStatus.num_running([merge_jid]) > 0
+  end
+
   def closed_without_fork?
     closed? && source_project_missing?
   end
@@ -725,12 +721,6 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  def locked_long_ago?
-    return false unless locked?
-
-    locked_at.nil? || locked_at < (Time.now - 1.day)
-  end
-
   def has_ci?
     has_ci_integration = source_project.try(:ci_service)
     uses_gitlab_ci = all_pipelines.any?
diff --git a/app/serializers/merge_request_entity.rb b/app/serializers/merge_request_entity.rb
index 7f17f2bf604..07650ce6f20 100644
--- a/app/serializers/merge_request_entity.rb
+++ b/app/serializers/merge_request_entity.rb
@@ -2,7 +2,6 @@ class MergeRequestEntity < IssuableEntity
   include RequestAwareEntity
 
   expose :in_progress_merge_commit_sha
-  expose :locked_at
   expose :merge_commit_sha
   expose :merge_error
   expose :merge_params
@@ -32,6 +31,7 @@ class MergeRequestEntity < IssuableEntity
   expose :head_pipeline, with: PipelineDetailsEntity, as: :pipeline
 
   # Booleans
+  expose :merge_ongoing?, as: :merge_ongoing
   expose :work_in_progress?, as: :work_in_progress
   expose :source_branch_exists?, as: :source_branch_exists
   expose :mergeable_discussions_state?, as: :mergeable_discussions_state
diff --git a/app/workers/merge_worker.rb b/app/workers/merge_worker.rb
index 48e2da338f6..c3b58df92c1 100644
--- a/app/workers/merge_worker.rb
+++ b/app/workers/merge_worker.rb
@@ -7,6 +7,8 @@ class MergeWorker
     current_user = User.find(current_user_id)
     merge_request = MergeRequest.find(merge_request_id)
 
+    merge_request.update_column(:merge_jid, jid)
+
     MergeRequests::MergeService.new(merge_request.target_project, current_user, params)
       .execute(merge_request)
   end
diff --git a/app/workers/stuck_merge_jobs_worker.rb b/app/workers/stuck_merge_jobs_worker.rb
new file mode 100644
index 00000000000..7843179d77c
--- /dev/null
+++ b/app/workers/stuck_merge_jobs_worker.rb
@@ -0,0 +1,34 @@
+class StuckMergeJobsWorker
+  include Sidekiq::Worker
+  include CronjobQueue
+
+  def perform
+    stuck_merge_requests.find_in_batches(batch_size: 100) do |group|
+      jids = group.map(&:merge_jid)
+
+      # Find the jobs that aren't currently running or that exceeded the threshold.
+      completed_jids = Gitlab::SidekiqStatus.completed_jids(jids)
+
+      if completed_jids.any?
+        completed_ids = group.select { |merge_request| completed_jids.include?(merge_request.merge_jid) }.map(&:id)
+
+        apply_current_state!(completed_jids, completed_ids)
+      end
+    end
+  end
+
+  private
+
+  def apply_current_state!(completed_jids, completed_ids)
+    merge_requests = MergeRequest.where(id: completed_ids)
+
+    merge_requests.where.not(merge_commit_sha: nil).update_all(state: :merged)
+    merge_requests.where(merge_commit_sha: nil).update_all(state: :opened)
+
+    Rails.logger.info("Updated state of locked merge jobs. JIDs: #{completed_jids.join(', ')}")
+  end
+
+  def stuck_merge_requests
+    MergeRequest.select('id, merge_jid').with_state(:locked).where.not(merge_jid: nil).reorder(nil)
+  end
+end
diff --git a/changelogs/unreleased/31207-clean-locked-merge-requests.yml b/changelogs/unreleased/31207-clean-locked-merge-requests.yml
new file mode 100644
index 00000000000..1f52987baef
--- /dev/null
+++ b/changelogs/unreleased/31207-clean-locked-merge-requests.yml
@@ -0,0 +1,4 @@
+---
+title: Unlock stuck merge request and set the proper state
+merge_request: 13207
+author:
diff --git a/config/initializers/1_settings.rb b/config/initializers/1_settings.rb
index 7a43bf939ea..396bc57bd64 100644
--- a/config/initializers/1_settings.rb
+++ b/config/initializers/1_settings.rb
@@ -395,6 +395,10 @@ Settings.cron_jobs['remove_old_web_hook_logs_worker'] ||= Settingslogic.new({})
 Settings.cron_jobs['remove_old_web_hook_logs_worker']['cron'] ||= '40 0 * * *'
 Settings.cron_jobs['remove_old_web_hook_logs_worker']['job_class'] = 'RemoveOldWebHookLogsWorker'
 
+Settings.cron_jobs['stuck_merge_jobs_worker'] ||= Settingslogic.new({})
+Settings.cron_jobs['stuck_merge_jobs_worker']['cron'] ||= '0 */2 * * *'
+Settings.cron_jobs['stuck_merge_jobs_worker']['job_class'] = 'StuckMergeJobsWorker'
+
 #
 # GitLab Shell
 #
diff --git a/db/migrate/20170731183033_add_merge_jid_to_merge_requests.rb b/db/migrate/20170731183033_add_merge_jid_to_merge_requests.rb
new file mode 100644
index 00000000000..a7d8f2f3604
--- /dev/null
+++ b/db/migrate/20170731183033_add_merge_jid_to_merge_requests.rb
@@ -0,0 +1,7 @@
+class AddMergeJidToMergeRequests < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    add_column :merge_requests, :merge_jid, :string
+  end
+end
diff --git a/db/migrate/20170801000000_remove_locked_at_column_from_merge_requests.rb b/db/migrate/20170801000000_remove_locked_at_column_from_merge_requests.rb
new file mode 100644
index 00000000000..ea3d1fb3e02
--- /dev/null
+++ b/db/migrate/20170801000000_remove_locked_at_column_from_merge_requests.rb
@@ -0,0 +1,11 @@
+class RemoveLockedAtColumnFromMergeRequests < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def up
+    remove_column :merge_requests, :locked_at
+  end
+
+  def down
+    add_column :merge_requests, :locked_at, :datetime_with_timezone
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index f2f35acef95..4816e1aefab 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -840,7 +840,6 @@ ActiveRecord::Schema.define(version: 20170803130232) do
     t.integer "target_project_id", null: false
     t.integer "iid"
     t.text "description"
-    t.datetime "locked_at"
     t.integer "updated_by_id"
     t.text "merge_error"
     t.text "merge_params"
@@ -858,6 +857,7 @@ ActiveRecord::Schema.define(version: 20170803130232) do
     t.integer "last_edited_by_id"
     t.integer "head_pipeline_id"
     t.boolean "ref_fetched"
+    t.string "merge_jid"
   end
 
   add_index "merge_requests", ["assignee_id"], name: "index_merge_requests_on_assignee_id", using: :btree
diff --git a/doc/user/project/integrations/webhooks.md b/doc/user/project/integrations/webhooks.md
index c03a2df9a72..47eb0b34f66 100644
--- a/doc/user/project/integrations/webhooks.md
+++ b/doc/user/project/integrations/webhooks.md
@@ -438,7 +438,6 @@ X-Gitlab-Event: Note Hook
     "iid": 1,
     "description": "Et voluptas corrupti assumenda temporibus. Architecto cum animi eveniet amet asperiores. Vitae numquam voluptate est natus sit et ad id.",
     "position": 0,
-    "locked_at": null,
     "source":{
       "name":"Gitlab Test",
       "description":"Aut reprehenderit ut est.",
diff --git a/spec/features/merge_requests/widget_spec.rb b/spec/features/merge_requests/widget_spec.rb
index 69e31c7481f..fd991293ee9 100644
--- a/spec/features/merge_requests/widget_spec.rb
+++ b/spec/features/merge_requests/widget_spec.rb
@@ -219,4 +219,17 @@ describe 'Merge request', :js do
       expect(page).to have_field('remove-source-branch-input', disabled: true)
     end
   end
+
+  context 'ongoing merge process' do
+    it 'shows Merging state' do
+      allow_any_instance_of(MergeRequest).to receive(:merge_ongoing?).and_return(true)
+
+      visit project_merge_request_path(project, merge_request)
+
+      wait_for_requests
+
+      expect(page).not_to have_button('Merge')
+      expect(page).to have_content('This merge request is in the process of being merged')
+    end
+  end
 end
diff --git a/spec/fixtures/api/schemas/entities/merge_request.json b/spec/fixtures/api/schemas/entities/merge_request.json
index 7ffa82fc4bd..2f12b671dec 100644
--- a/spec/fixtures/api/schemas/entities/merge_request.json
+++ b/spec/fixtures/api/schemas/entities/merge_request.json
@@ -19,7 +19,6 @@
     "human_time_estimate": { "type": ["integer", "null"] },
     "human_total_time_spent": { "type": ["integer", "null"] },
     "in_progress_merge_commit_sha": { "type": ["string", "null"] },
-    "locked_at": { "type": ["string", "null"] },
     "merge_error": { "type": ["string", "null"] },
     "merge_commit_sha": { "type": ["string", "null"] },
     "merge_params": { "type": ["object", "null"] },
@@ -94,7 +93,8 @@
     "commit_change_content_path": { "type": "string" },
     "remove_wip_path": { "type": "string" },
     "commits_count": { "type": "integer" },
-    "remove_source_branch": { "type": ["boolean", "null"] }
+    "remove_source_branch": { "type": ["boolean", "null"] },
+    "merge_ongoing": { "type": "boolean" }
   },
   "additionalProperties": false
 }
diff --git a/spec/javascripts/vue_mr_widget/components/states/mr_widget_locked_spec.js b/spec/javascripts/vue_mr_widget/components/states/mr_widget_locked_spec.js
index fb2ef606604..237035648cf 100644
--- a/spec/javascripts/vue_mr_widget/components/states/mr_widget_locked_spec.js
+++ b/spec/javascripts/vue_mr_widget/components/states/mr_widget_locked_spec.js
@@ -1,10 +1,10 @@
 import Vue from 'vue';
-import lockedComponent from '~/vue_merge_request_widget/components/states/mr_widget_locked';
+import mergingComponent from '~/vue_merge_request_widget/components/states/mr_widget_merging';
 
-describe('MRWidgetLocked', () => {
+describe('MRWidgetMerging', () => {
   describe('props', () => {
     it('should have props', () => {
-      const { mr } = lockedComponent.props;
+      const { mr } = mergingComponent.props;
 
       expect(mr.type instanceof Object).toBeTruthy();
       expect(mr.required).toBeTruthy();
@@ -13,7 +13,7 @@ describe('MRWidgetLocked', () => {
 
   describe('template', () => {
     it('should have correct elements', () => {
-      const Component = Vue.extend(lockedComponent);
+      const Component = Vue.extend(mergingComponent);
       const mr = {
         targetBranchPath: '/branch-path',
         targetBranch: 'branch',
@@ -24,7 +24,7 @@ describe('MRWidgetLocked', () => {
       }).$el;
 
       expect(el.classList.contains('mr-widget-body')).toBeTruthy();
-      expect(el.innerText).toContain('it is locked');
+      expect(el.innerText).toContain('This merge request is in the process of being merged');
       expect(el.innerText).toContain('changes will be merged into');
       expect(el.querySelector('.label-branch a').getAttribute('href')).toEqual(mr.targetBranchPath);
       expect(el.querySelector('.label-branch a').textContent).toContain(mr.targetBranch);
diff --git a/spec/javascripts/vue_mr_widget/mock_data.js b/spec/javascripts/vue_mr_widget/mock_data.js
index ad2f28b24f0..0795d0aaa82 100644
--- a/spec/javascripts/vue_mr_widget/mock_data.js
+++ b/spec/javascripts/vue_mr_widget/mock_data.js
@@ -20,7 +20,6 @@ export default {
   "human_time_estimate": null,
   "human_total_time_spent": null,
   "in_progress_merge_commit_sha": null,
-  "locked_at": null,
   "merge_commit_sha": "53027d060246c8f47e4a9310fb332aa52f221775",
   "merge_error": null,
   "merge_params": {
diff --git a/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js b/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js
index 3a0c50b750f..669ee248bf1 100644
--- a/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js
+++ b/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js
@@ -342,7 +342,7 @@ describe('mrWidgetOptions', () => {
       expect(comps['mr-widget-related-links']).toBeDefined();
       expect(comps['mr-widget-merged']).toBeDefined();
       expect(comps['mr-widget-closed']).toBeDefined();
-      expect(comps['mr-widget-locked']).toBeDefined();
+      expect(comps['mr-widget-merging']).toBeDefined();
       expect(comps['mr-widget-failed-to-merge']).toBeDefined();
       expect(comps['mr-widget-wip']).toBeDefined();
       expect(comps['mr-widget-archived']).toBeDefined();
diff --git a/spec/lib/gitlab/import_export/project.json b/spec/lib/gitlab/import_export/project.json
index 469a014e4d2..4e631e13410 100644
--- a/spec/lib/gitlab/import_export/project.json
+++ b/spec/lib/gitlab/import_export/project.json
@@ -2534,7 +2534,6 @@
       "iid": 9,
       "description": null,
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -2983,7 +2982,6 @@
       "iid": 8,
       "description": null,
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -3267,7 +3265,6 @@
       "iid": 7,
       "description": "Et commodi deserunt aspernatur vero rerum. Ut non dolorum alias in odit est libero. Voluptatibus eos in et vitae repudiandae facilis ex mollitia.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -3551,7 +3548,6 @@
       "iid": 6,
       "description": "Dicta magnam non voluptates nam dignissimos nostrum deserunt. Dolorum et suscipit iure quae doloremque. Necessitatibus saepe aut labore sed.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -4241,7 +4237,6 @@
       "iid": 5,
       "description": "Est eaque quasi qui qui. Similique voluptatem impedit iusto ratione reprehenderit. Itaque est illum ut nulla aut.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -4789,7 +4784,6 @@
       "iid": 4,
       "description": "Nam magnam odit velit rerum. Sapiente dolore sunt saepe debitis. Culpa maiores ut ad dolores dolorem et.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -5288,7 +5282,6 @@
       "iid": 3,
       "description": "Libero nesciunt mollitia quis odit eos vero quasi. Iure voluptatem ut sint pariatur voluptates ut aut. Laborum possimus unde illum ipsum eum.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -5548,7 +5541,6 @@
       "iid": 2,
       "description": "Ut dolor quia aliquid dolore et nisi. Est minus suscipit enim quaerat sapiente consequatur rerum. Eveniet provident consequatur dolor accusantium reiciendis.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
@@ -6238,7 +6230,6 @@
       "iid": 1,
       "description": "Eveniet nihil ratione veniam similique qui aut sapiente tempora. Sed praesentium iusto dignissimos possimus id repudiandae quo nihil. Qui doloremque autem et iure fugit.",
       "position": 0,
-      "locked_at": null,
       "updated_by_id": null,
       "merge_error": null,
       "merge_params": {
diff --git a/spec/lib/gitlab/import_export/safe_model_attributes.yml b/spec/lib/gitlab/import_export/safe_model_attributes.yml
index 11f4c16ff96..4dce48f8079 100644
--- a/spec/lib/gitlab/import_export/safe_model_attributes.yml
+++ b/spec/lib/gitlab/import_export/safe_model_attributes.yml
@@ -145,7 +145,6 @@ MergeRequest:
 - iid
 - description
 - position
-- locked_at
 - updated_by_id
 - merge_error
 - merge_params
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 3402c260f27..a1a3e70a7d2 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -1369,6 +1369,32 @@ describe MergeRequest do
     end
   end
 
+  describe '#merge_ongoing?' do
+    it 'returns true when merge process is ongoing for merge_jid' do
+      merge_request = create(:merge_request, merge_jid: 'foo')
+
+      allow(Gitlab::SidekiqStatus).to receive(:num_running).with(['foo']).and_return(1)
+
+      expect(merge_request.merge_ongoing?).to be(true)
+    end
+
+    it 'returns false when no merge process running for merge_jid' do
+      merge_request = build(:merge_request, merge_jid: 'foo')
+
+      allow(Gitlab::SidekiqStatus).to receive(:num_running).with(['foo']).and_return(0)
+
+      expect(merge_request.merge_ongoing?).to be(false)
+    end
+
+    it 'returns false when merge_jid is nil' do
+      merge_request = build(:merge_request, merge_jid: nil)
+
+      expect(Gitlab::SidekiqStatus).not_to receive(:num_running)
+
+      expect(merge_request.merge_ongoing?).to be(false)
+    end
+  end
+
   describe "#closed_without_fork?" do
     let(:project)      { create(:project) }
     let(:fork_project) { create(:project, forked_from_project: project) }
diff --git a/spec/serializers/merge_request_entity_spec.rb b/spec/serializers/merge_request_entity_spec.rb
index 18cd9e9c006..a2fd5b7daae 100644
--- a/spec/serializers/merge_request_entity_spec.rb
+++ b/spec/serializers/merge_request_entity_spec.rb
@@ -47,7 +47,7 @@ describe MergeRequestEntity do
                                :cancel_merge_when_pipeline_succeeds_path,
                                :create_issue_to_resolve_discussions_path,
                                :source_branch_path, :target_branch_commits_path,
-                               :target_branch_tree_path, :commits_count)
+                               :target_branch_tree_path, :commits_count, :merge_ongoing)
   end
 
   it 'has email_patches_path' do
diff --git a/spec/workers/merge_worker_spec.rb b/spec/workers/merge_worker_spec.rb
index 303193bab9b..ee51000161a 100644
--- a/spec/workers/merge_worker_spec.rb
+++ b/spec/workers/merge_worker_spec.rb
@@ -27,4 +27,15 @@ describe MergeWorker do
       expect(source_project.repository.branch_names).not_to include('markdown')
     end
   end
+
+  it 'persists merge_jid' do
+    merge_request = create(:merge_request, merge_jid: nil)
+    user = create(:user)
+    worker = described_class.new
+
+    allow(worker).to receive(:jid) { '999' }
+
+    expect { worker.perform(merge_request.id, user.id, {}) }
+      .to change { merge_request.reload.merge_jid }.from(nil).to('999')
+  end
 end
diff --git a/spec/workers/stuck_merge_jobs_worker_spec.rb b/spec/workers/stuck_merge_jobs_worker_spec.rb
new file mode 100644
index 00000000000..a5ad78393c9
--- /dev/null
+++ b/spec/workers/stuck_merge_jobs_worker_spec.rb
@@ -0,0 +1,50 @@
+require 'spec_helper'
+
+describe StuckMergeJobsWorker do
+  describe 'perform' do
+    let(:worker) { described_class.new }
+
+    context 'merge job identified as completed' do
+      it 'updates merge request to merged when locked but has merge_commit_sha' do
+        allow(Gitlab::SidekiqStatus).to receive(:completed_jids).and_return(%w(123 456))
+        mr_with_sha = create(:merge_request, :locked, merge_jid: '123', state: :locked, merge_commit_sha: 'foo-bar-baz')
+        mr_without_sha = create(:merge_request, :locked, merge_jid: '123', state: :locked, merge_commit_sha: nil)
+
+        worker.perform
+
+        expect(mr_with_sha.reload).to be_merged
+        expect(mr_without_sha.reload).to be_opened
+      end
+
+      it 'updates merge request to opened when locked but has not been merged' do
+        allow(Gitlab::SidekiqStatus).to receive(:completed_jids).and_return(%w(123))
+        merge_request = create(:merge_request, :locked, merge_jid: '123', state: :locked)
+
+        worker.perform
+
+        expect(merge_request.reload).to be_opened
+      end
+
+      it 'logs updated stuck merge job ids' do
+        allow(Gitlab::SidekiqStatus).to receive(:completed_jids).and_return(%w(123 456))
+
+        create(:merge_request, :locked, merge_jid: '123')
+        create(:merge_request, :locked, merge_jid: '456')
+
+        expect(Rails).to receive_message_chain(:logger, :info).with('Updated state of locked merge jobs. JIDs: 123, 456')
+
+        worker.perform
+      end
+    end
+
+    context 'merge job not identified as completed' do
+      it 'does not change merge request state when job is not completed yet' do
+        allow(Gitlab::SidekiqStatus).to receive(:completed_jids).and_return([])
+
+        merge_request = create(:merge_request, :locked, merge_jid: '123')
+
+        expect { worker.perform }.not_to change { merge_request.reload.state }.from('locked')
+      end
+    end
+  end
+end