Error 500 creating merge requests

Summary

An Error 500 occurs when creating a merge request. (Using Gitlab 10.2.1)

Steps to reproduce

• Create a merge request
• Click on the submit button
• Error 500

Example Project

Tested on gitlab.com but NOT reproduced

What is the current bug behavior?

An error 500 is blocking the MR creation

What is the expected correct behavior?

No error should block the MR creation

Relevant logs and/or screenshots

/var/log/gitlab/gitlab-rails/production.log

Started POST "/obfuscated/obfuscated/merge_requests" for 192.168.1.obfuscated at 2017-11-23 09:16:15 +0100
Started PATCH "/api/v4/jobs/119401/trace" for 192.168.1.obfuscated at 2017-11-23 09:16:15 +0100
Processing by Projects::MergeRequests::CreationsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"[FILTERED]", "merge_request"=>{"title"=>"WIP: obfuscated", "description"=>"", "assignee_id"=>"", "label_ids"=>[""], "force_remove_source_branch"=>"0", "lock_version"=>"", "source_project_id"=>"255", "sourc
e_branch"=>"obfuscated", "target_project_id"=>"255", "target_branch"=>"develop"}, "namespace_id"=>"obfuscated", "project_id"=>"obfuscated"}
Completed 500 Internal Server Error in 93ms (ActiveRecord: 12.0ms)

ActiveRecord::StatementInvalid (PG::UndefinedColumn: ERROR:  column "latest_merge_request_diff_id" does not exist
LINE 1: ..."."deleted_at" IS NULL AND (id = 914 AND COALESCE(latest_mer...
                                                             ^
: UPDATE "merge_requests" SET "latest_merge_request_diff_id" = 1841 WHERE "merge_requests"."deleted_at" IS NULL AND (id = 914 AND COALESCE(latest_merge_request_diff_id, 0) < 1841)):
  app/models/merge_request_diff.rb:53:in `save_git_content'
  app/models/merge_request.rb:432:in `block in create_merge_request_diff'
  lib/gitlab/gitaly_client.rb:218:in `allow_n_plus_1_calls'
  app/models/merge_request.rb:431:in `create_merge_request_diff'
  app/models/merge_request.rb:424:in `ensure_merge_request_diff'
  app/services/issuable_base_service.rb:121:in `block in create_issuable'
  app/services/issuable_base_service.rb:120:in `create_issuable'
  app/services/issuable_base_service.rb:140:in `create'
  app/services/merge_requests/create_service.rb:18:in `block in execute'
  lib/gitlab/gitaly_client.rb:218:in `allow_n_plus_1_calls'
  app/services/merge_requests/create_service.rb:17:in `execute'
  app/controllers/projects/merge_requests/creations_controller.rb:17:in `create'
  lib/gitlab/i18n.rb:47:in `with_locale'
  lib/gitlab/i18n.rb:53:in `with_user_locale'
  app/controllers/application_controller.rb:336:in `set_locale'
  lib/gitlab/middleware/multipart.rb:93:in `call'
  lib/gitlab/request_profiler/middleware.rb:14:in `call'
  lib/gitlab/middleware/go.rb:18:in `call'
  lib/gitlab/etag_caching/middleware.rb:11:in `call'
  lib/gitlab/middleware/read_only.rb:31:in `call'
  lib/gitlab/request_context.rb:18:in `call'
  lib/gitlab/metrics/requests_rack_middleware.rb:27:in `call'


Started PATCH "/api/v4/jobs/119401/trace" for 192.168.1.obfuscated at 2017-11-23 09:16:18 +0100

Output of checks

This bug DOES NOT happen on GitLab.com

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:         Ubuntu 16.04
Current User:   git
Using RVM:      no
Ruby Version:   2.3.5p376
Gem Version:    2.6.13
Bundler Version:1.13.7
Rake Version:   12.1.0
Redis Version:  3.2.5
Git Version:    2.13.6
Sidekiq Version:5.0.4
Go Version:     unknown
GitLab information
Version:        10.2.1
Revision:       eb2643f
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     postgresql
URL:            http://192.168.1.obfuscated
HTTP Clone URL: http://192.168.1.obfuscated/some-group/some-project.git
SSH Clone URL:  git@192.168.1.obfuscated:some-group/some-project.git
Using LDAP:     no
Using Omniauth: no
GitLab Shell
Version:        5.9.4
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab Shell ...
GitLab Shell version >= 5.9.4 ? ... OK (5.9.4)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
3/9 ... ok
3/10 ... ok
3/11 ... ok
2/12 ... ok
2/13 ... ok
2/14 ... ok
2/15 ... ok
2/16 ... ok
2/17 ... ok
2/18 ... ok
2/19 ... ok
2/20 ... ok
2/21 ... ok
2/22 ... ok
2/23 ... ok
3/25 ... ok
2/26 ... ok
12/27 ... ok
3/28 ... ok
3/30 ... ok
3/32 ... ok
3/33 ... ok
3/34 ... ok
3/35 ... ok
3/36 ... ok
3/37 ... ok
3/49 ... ok
3/53 ... ok
3/54 ... ok
12/55 ... ok
12/56 ... ok
12/57 ... ok
12/59 ... ok
12/60 ... ok
3/61 ... ok
12/62 ... ok
12/63 ... ok
3/64 ... ok
12/84 ... ok
2/88 ... ok
5/89 ... ok
12/90 ... ok
12/91 ... ok
10/96 ... ok
3/99 ... ok
2/100 ... ok
3/101 ... ok
10/102 ... ok
3/104 ... ok
3/105 ... ok
3/108 ... ok
3/109 ... ok
3/113 ... ok
2/115 ... ok
2/117 ... ok
12/119 ... ok
2/121 ... ok
2/122 ... ok
2/128 ... ok
2/129 ... ok
3/132 ... ok
3/133 ... ok
12/134 ... ok
2/135 ... ok
2/136 ... ok
3/137 ... ok
3/138 ... ok
3/139 ... ok
3/140 ... ok
3/142 ... ok
3/144 ... ok
2/145 ... ok
3/146 ... ok
12/147 ... ok
3/148 ... ok
10/149 ... ok
3/150 ... ok
2/151 ... ok
3/152 ... ok
12/154 ... ok
3/155 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Sidekiq ...
Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Reply by email ...
IMAP server credentials are correct? ... no
Try fixing it:
An error occurred: OpenSSL::SSL::SSLError: hostname "obfuscated.com" does not match the server certificate
Check that the information in config/gitlab.yml is correct
For more information see:
doc/administration/reply_by_email.md
Please fix the error above and rerun the checks.
Init.d configured correctly? ... skipped
MailRoom running? ... skipped
Checking Reply by email ... Finished
Checking LDAP ...
LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/9 ... yes
3/10 ... yes
3/11 ... yes
2/12 ... yes
2/13 ... yes
2/14 ... yes
2/15 ... yes
2/16 ... yes
2/17 ... yes
2/18 ... yes
2/19 ... yes
2/20 ... yes
2/21 ... yes
2/22 ... yes
2/23 ... yes
3/25 ... yes
2/26 ... yes
12/27 ... yes
3/28 ... yes
3/30 ... yes
3/32 ... yes
3/33 ... yes
3/34 ... yes
3/35 ... yes
3/36 ... yes
3/37 ... yes
3/49 ... yes
3/53 ... yes
3/54 ... yes
12/55 ... yes
12/56 ... yes
12/57 ... yes
12/59 ... yes
12/60 ... yes
3/61 ... yes
12/62 ... yes
12/63 ... yes
3/64 ... yes
12/84 ... yes
2/88 ... yes
5/89 ... yes
12/90 ... yes
12/91 ... yes
10/96 ... yes
3/99 ... yes
2/100 ... yes
3/101 ... yes
10/102 ... yes
3/104 ... yes
3/105 ... yes
3/108 ... yes
3/109 ... yes
3/113 ... yes
2/115 ... yes
2/117 ... yes
12/119 ... yes
2/121 ... yes
2/122 ... yes
2/128 ... yes
2/129 ... yes
3/132 ... yes
3/133 ... yes
12/134 ... yes
2/135 ... yes
2/136 ... yes
3/137 ... yes
3/138 ... yes
3/139 ... yes
3/140 ... yes
3/142 ... yes
3/144 ... yes
2/145 ... yes
3/146 ... yes
12/147 ... yes
3/148 ... yes
10/149 ... yes
3/150 ... yes
2/151 ... yes
3/152 ... yes
12/154 ... yes
3/155 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.3.5)
Git version >= 2.7.3 ? ... yes (2.13.6)
Git user has default SSH configuration? ... yes
Active users: ... 10
Checking GitLab ... Finished

Possible fixes

Seems like an SQL issue, failed update?