Allow asynchronous rebase operations to be monitored

This MR introduces tracking of the `rebase_jid` for merge requests. As
with `merge_ongoing?`, `rebase_in_progress?` will now return true if a
rebase is proceeding in sidekiq.

After one release, we should remove the Gitaly-based lookup of rebases.
It is much better to track this kind of thing via the database.

3 files changed, 7 insertions, 2 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index 20f8c637274..42499c5b41e 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -52,7 +52,10 @@ module API
       rack_response({ 'message' => '404 Not found' }.to_json, 404)
     end
 
-    rescue_from ::Gitlab::ExclusiveLeaseHelpers::FailedToObtainLockError do
+    rescue_from(
+      ::ActiveRecord::StaleObjectError,
+      ::Gitlab::ExclusiveLeaseHelpers::FailedToObtainLockError
+    ) do
       rack_response({ 'message' => '409 Conflict: Resource lock' }.to_json, 409)
     end
 
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 6b8c1a2c0e8..64ee82cd775 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -429,9 +429,10 @@ module API
 
         authorize_push_to_merge_request!(merge_request)
 
-        RebaseWorker.perform_async(merge_request.id, current_user.id)
+        merge_request.rebase_async(current_user.id)
 
         status :accepted
+        present rebase_in_progress: merge_request.rebase_in_progress?
       end
 
       desc 'List issues that will be closed on merge' do
diff --git a/lib/gitlab/import_export/import_export.yml b/lib/gitlab/import_export/import_export.yml
index a0fb051e806..01437c67fa9 100644
--- a/lib/gitlab/import_export/import_export.yml
+++ b/lib/gitlab/import_export/import_export.yml
@@ -160,6 +160,7 @@ excluded_attributes:
     - :milestone_id
     - :ref_fetched
     - :merge_jid
+    - :rebase_jid
     - :latest_merge_request_diff_id
   award_emoji:
     - :awardable_id