Merge request "requires undefined more approvals" after upgrade from 8.15.4-ee.1 to 8.16.1-ee.0

I'm submitting a support request in parallel, but I figured it would be useful to go ahead and file a bug for the issue we're experiencing, partly to provide more info for the support request but mostly so people can find it if they experience the same issue (we couldn't find anything when searching for "requires undefined more approvals").

Summary

After running an in-place upgrade from 8.15.4 to 8.16.1, previous merge requests and new merge requests show "Requires undefined more approvals" regardless of the number of approvals required in the project settings or the number on the merge request.

Steps to reproduce

  • With version 8.15.4-ee.1 installed, containing a project that has at least 1 merge approval required in the project settings, run apt install gitlab-ee to upgrade to 8.16.1-ee.0.
  • Create a new merge request or view an existing merge request.

Expected behavior

If n more approvals a required, shows "Requires n more approvals". When all required approvals are in, the merge request can be accepted.

Actual behavior

Shows "Requires undefined more approvals", regardless of the remaining required approvals. The "accept merge request" button is present, and clicking it brings up a notification saying "Something went wrong on our end."

Relevant logs and/or screenshots

Screenshot_from_2017-01-23_13-58-47

/var/log/gitlab/gitlab-rails/production.log doesn't seem to show any errors:

Started GET "/[REDACTED]/[REDACTED]/merge_requests/882" for 192.168.251.202 at 2017-01-23 13:56:26 -0700
Processing by Projects::MergeRequestsController#show as HTML                     
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Completed 200 OK in 841ms (Views: 700.9ms | ActiveRecord: 47.9ms)                
Started GET "/[REDACTED]/[REDACTED]/merge_requests/882/ci_status" for 192.168.251.202 at 2017-01-23 13:56:27 -0700
Started GET "/[REDACTED]/[REDACTED]/merge_requests/882/ci_environments_status" for 192.168.251.202 at 2017-01-23 13:56:27 -0700
Started GET "/[REDACTED]/[REDACTED]/merge_requests/882.json" for 192.168.251.202 at 2017-01-23 13:56:27 -0700
Processing by Projects::MergeRequestsController#ci_environments_status as JSON   
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Processing by Projects::MergeRequestsController#ci_status as JSON                
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Processing by Projects::MergeRequestsController#show as JSON                     
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Started GET "/[REDACTED]/[REDACTED]/merge_requests/882/approvals" for 192.168.251.202 at 2017-01-23 13:56:28 -0700
Started GET "/[REDACTED]/[REDACTED]/merge_requests/882/merge_check" for 192.168.251.202 at 2017-01-23 13:56:28 -0700
Completed 200 OK in 86ms (Views: 0.6ms | ActiveRecord: 10.1ms)                   
Processing by Projects::MergeRequestsController#approvals as JSON                
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Processing by Projects::MergeRequestsController#merge_check as */*               
  Parameters: {"namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}                                                                                                    
Completed 200 OK in 99ms (Views: 0.3ms | ActiveRecord: 16.3ms)                   
Completed 200 OK in 105ms (Views: 3.0ms | ActiveRecord: 9.9ms)                   
Completed 200 OK in 104ms (Views: 42.6ms | ActiveRecord: 13.4ms)

When clicking "Accept merge request", the Javascript console shows a 404 for .../merge_requests/882/merge, and the production.log agrees:

Started POST "/[REDACTED]/[REDACTED]/merge_requests/882/merge" for 192.168.251.202 at 2017-01-23 13:59:12 -0700
Processing by Projects::MergeRequestsController#merge as JS
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"[REDACTED]", "sha"=>"54df0856448ed0469249d33733bb8a903f026b03"
, "commit_message"=>"Merge branch '[REDACTED]' into 'master'\r\n\r\n[REDACTED]\r\n\r\nCloses #1156\r\n\r\nSee merge request
 !882", "merge_when_build_succeeds"=>"", "button"=>"", "namespace_id"=>"[REDACTED]", "project_id"=>"[REDACTED]", "id"=>"882"}
Completed 404 Not Found in 105ms (Views: 0.7ms | ActiveRecord: 12.9ms)

Output of checks

Results of GitLab application Check

We started a revert before getting this far in the bug report template, so we don't have this. Sorry.

Results of GitLab environment info

We started a revert before getting this far in the bug report template, so we don't have this. Sorry.

Possible fixes

Unknown.