Error: (undefined method `default_branch' for nil:NilClass) - Error 500 on every page

Summary

After pushing to master branch and creating/merging a merge request gitlab stops working for a specific user. It always shows a 500 while other users are still able to use gitlab as normal. But access to the specific repository results in a 500 for every user.

Steps to reproduce

  1. push to master branch
  2. create merge request (master => release)
  3. click on merge button
  4. => shows a 404 on the projects page and a 500 on all other pages (except the admin area)

Of course this is not always reproducable, but this is the third time it happend.

What is the current bug behavior?

The user which creates the merge request can't use gitlab anymore. Every page results in a 500 or 404 while other users can use gitlab as normal (except the specific repository which will be a 500/404 for everyone)

Relevant logs and/or screenshots

production.log while clicking on merge button

Started POST "/myproject/merge_requests/6/merge" for 10.0.13.103 at 2018-03-21 09:36:12 +0100
Processing by Projects::MergeRequestsController#merge as JSON
  Parameters: {"sha"=>"a4f079da2e21eb8b2cc59d1a0d0d791b2c6a1d80", "commit_message"=>"Merge branch 'master' into 'release'\n\nchore(smoke): allow to fail\n\nSee merge request myproject!6", "merge_when_pipeline_succeeds"=>false, "should_remove_source_branch"=>false, "namespace_id"=>"/", "project_id"=>"docker", "id"=>"6", "merge_request"=>{"merge_when_pipeline_succeeds"=>false}}
Completed 200 OK in 102ms (Views: 0.4ms | ActiveRecord: 38.6ms)
Started GET "/myproject/merge_requests/6.json?serializer=basic" for 10.0.13.103 at 2018-03-21 09:36:12 +0100
Processing by Projects::MergeRequestsController#show as JSON
  Parameters: {"serializer"=>"basic", "namespace_id"=>"/", "project_id"=>"docker", "id"=>"6"}
myproject!6 - Git merge started on JID
Completed 200 OK in 68ms (Views: 0.4ms | ActiveRecord: 29.5ms)
Started POST "/api/v4/internal/allowed" for 127.0.0.1 at 2018-03-21 09:36:12 +0100
Started POST "/api/v4/internal/pre_receive" for 127.0.0.1 at 2018-03-21 09:36:13 +0100
Started POST "/api/v4/internal/post_receive" for 127.0.0.1 at 2018-03-21 09:36:13 +0100
myproject!6 - Git merge finished on JID  commit bff28eda3060bd7106070668d6305f646013bfd5
myproject!6 - Post merge started on JID  with state locked
myproject!6 - Post merge finished on JID  with state merged
myproject!6 - Merge process finished on JID  with state merged
Started GET "/admin/sidekiq/stats" for 10.0.13.104 at 2018-03-21 09:36:13 +0100
Started GET "/myproject/merge_requests/6.json?serializer=basic" for 10.0.13.103 at 2018-03-21 09:36:14 +0100
Processing by ApplicationController#route_not_found as JSON
  Parameters: {"serializer"=>"basic", "unmatched_route"=>"myproject/merge_requests/6"}
Completed 404 Not Found in 11ms (ActiveRecord: 3.0ms)
Started GET "/help" for 127.0.0.1 at 2018-03-21 09:36:16 +0100
Processing by HelpController#index as */*
Completed 200 OK in 53ms (Views: 50.0ms | ActiveRecord: 0.0ms)
Started GET "/myproject/merge_requests/6" for 10.0.13.103 at 2018-03-21 09:36:18 +0100
Processing by ApplicationController#route_not_found as HTML
  Parameters: {"unmatched_route"=>"myproject/merge_requests/6"}
Completed 404 Not Found in 101ms (Views: 84.0ms | ActiveRecord: 8.8ms)
Started GET "/admin/sidekiq/stats" for 10.0.13.104 at 2018-03-21 09:36:18 +0100
Started GET "/myproject/merge_requests/6" for 10.0.13.103 at 2018-03-21 09:36:19 +0100
Processing by ApplicationController#route_not_found as HTML
  Parameters: {"unmatched_route"=>"myproject/merge_requests/6"}
Completed 404 Not Found in 119ms (Views: 100.3ms | ActiveRecord: 8.3ms)
Started GET "/myproject" for 10.0.13.103 at 2018-03-21 09:36:22 +0100
Processing by ApplicationController#route_not_found as HTML
   Parameters: {"unmatched_route"=>"myproject"}

error inside the production.log while trying to access gitlab



ActionView::Template::Error (undefined method `default_branch' for nil:NilClass):
    1: - event = last_push_event
    2: - if event && show_last_push_widget?(event)
    3:   .row-content-block.top-block.hidden-xs.white
    4:     .event-last-push
    5:       .event-last-push-text
  app/models/push_event.rb:106:in `last_push_to_non_root?'
  app/helpers/application_helper.rb:109:in `show_last_push_widget?'
  app/views/projects/_last_push.html.haml:2:in `_app_views_projects__last_push_html_haml__1702220975205412547_70332644478280'
  app/views/dashboard/projects/starred.html.haml:8:in `_app_views_dashboard_projects_starred_html_haml___894380166290798882_70332491082960'
  app/controllers/dashboard/projects_controller.rb:31:in `starred'
  lib/gitlab/i18n.rb:47:in `with_locale'
  lib/gitlab/i18n.rb:53:in `with_user_locale'
  app/controllers/application_controller.rb:325:in `set_locale'
  lib/gitlab/middleware/multipart.rb:95:in `call'
  lib/gitlab/request_profiler/middleware.rb:14:in `call'
  lib/gitlab/middleware/go.rb:17: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'

It seems to be that the widget which is shown after a push to a branch on the top of a page is causing the 500. If I try to access the admin area directly by url I don't get a 500 (because the widget won't be shown in the admin area)

Output of checks

This happens on our Gitlab official docker image

Results of GitLab environment info

Expand for output related to GitLab environment info 
System information
System:
Current User:	git
Using RVM:	no
Ruby Version:	2.3.6p384
Gem Version:	2.6.13
Bundler Version:1.13.7
Rake Version:	12.3.0
Redis Version:	3.2.11
Git Version:	2.14.3
Sidekiq Version:5.0.5
Go Version:	unknown

GitLab information
Version:	10.5.6
Revision:	4b41d48
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		http://gitlab.dev-mc.de
HTTP Clone URL:	http://gitlab.dev-mc.de/some-group/some-project.git
SSH Clone URL:	git@gitlab.dev-mc.de:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	no


GitLab Shell
Version:	6.0.3
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 >= 6.0.3 ? ... OK (6.0.3)
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: ...
32/112 ... ok
32/113 ... ok
101/114 ... ok
52/115 ... ok
32/116 ... ok
51/117 ... ok
51/118 ... ok
51/119 ... ok
51/120 ... ok
53/121 ... ok
50/122 ... ok
32/123 ... ok
32/124 ... ok
104/125 ... ok
48/126 ... ok
37/127 ... ok
99/128 ... ok
37/129 ... ok
37/130 ... ok
37/132 ... ok
37/133 ... ok
106/134 ... ok
45/135 ... ok
44/136 ... ok
44/137 ... ok
37/138 ... ok
32/139 ... ok
46/140 ... ok
37/141 ... ok
37/142 ... repository is empty
37/143 ... ok
37/144 ... ok
34/145 ... ok
34/146 ... ok
34/147 ... ok
34/148 ... ok
34/149 ... ok
34/150 ... ok
34/151 ... ok
34/152 ... ok
34/153 ... ok
34/154 ... ok
34/155 ... ok
43/156 ... ok
32/157 ... ok
37/158 ... ok
37/159 ... ok
37/160 ... ok
37/161 ... ok
39/162 ... ok
79/163 ... ok
34/164 ... ok
42/165 ... ok
42/166 ... ok
32/167 ... ok
32/168 ... ok
32/169 ... ok
74/170 ... ok
42/171 ... ok
42/172 ... ok
37/173 ... ok
54/174 ... ok
35/175 ... ok
35/176 ... ok
103/177 ... ok
32/178 ... ok
35/179 ... ok
35/180 ... ok
54/181 ... ok
35/182 ... ok
54/183 ... ok
54/184 ... ok
40/186 ... ok
56/187 ... ok
56/188 ... ok
38/189 ... ok
34/190 ... ok
57/191 ... ok
57/192 ... ok
56/193 ... ok
33/194 ... ok
33/195 ... ok
33/196 ... ok
33/197 ... ok
33/198 ... ok
69/199 ... ok
40/200 ... ok
41/201 ... ok
41/202 ... ok
34/203 ... ok
34/204 ... ok
55/206 ... ok
59/207 ... ok
59/208 ... ok
58/209 ... ok
54/210 ... ok
58/211 ... ok
58/212 ... ok
32/213 ... ok
32/214 ... ok
32/215 ... ok
58/216 ... ok
51/217 ... ok
51/218 ... ok
63/219 ... ok
63/221 ... ok
73/222 ... ok
73/223 ... ok
66/228 ... ok
33/229 ... ok
69/230 ... ok
36/234 ... ok
36/236 ... ok
36/237 ... ok
36/238 ... ok
36/239 ... ok
56/240 ... ok
62/244 ... ok
36/245 ... ok
2/246 ... ok
58/248 ... ok
63/249 ... ok
59/250 ... ok
70/251 ... ok
70/252 ... ok
70/253 ... ok
70/254 ... ok
36/255 ... ok
72/257 ... ok
72/258 ... ok
72/259 ... ok
72/260 ... ok
73/263 ... repository is empty
74/264 ... ok
36/267 ... ok
77/268 ... ok
77/269 ... ok
34/270 ... ok
78/271 ... ok
78/272 ... ok
78/273 ... ok
36/274 ... ok
79/275 ... ok
80/280 ... ok
36/281 ... ok
34/283 ... ok
81/285 ... ok
2/286 ... ok
33/287 ... ok
82/288 ... ok
82/289 ... ok
82/290 ... ok
83/291 ... ok
62/292 ... ok
66/295 ... ok
84/296 ... ok
84/297 ... ok
84/298 ... ok
57/299 ... ok
87/305 ... ok
62/307 ... ok
36/314 ... ok
36/316 ... ok
36/317 ... ok
90/318 ... ok
58/319 ... ok
61/320 ... ok
61/322 ... ok
22/323 ... ok
22/324 ... ok
32/325 ... ok
32/326 ... repository is empty
61/328 ... ok
61/329 ... ok
22/331 ... ok
62/332 ... ok
36/333 ... ok
32/339 ... ok
36/340 ... ok
62/341 ... ok
32/342 ... ok
62/343 ... ok
71/344 ... ok
61/345 ... ok
2/346 ... ok
95/348 ... ok
32/349 ... repository is empty
96/350 ... ok
62/351 ... ok
61/352 ... ok
96/354 ... ok
32/355 ... ok
32/358 ... repository is empty
95/359 ... ok
95/360 ... ok
36/361 ... ok
99/362 ... ok
61/363 ... ok
36/364 ... ok
100/365 ... ok
100/366 ... ok
101/367 ... ok
36/369 ... ok
36/370 ... ok
103/371 ... ok
104/373 ... ok
105/375 ... ok
105/376 ... ok
105/377 ... ok
62/379 ... ok
62/380 ... ok
106/381 ... ok
36/382 ... ok
57/383 ... ok
107/384 ... ok
36/385 ... ok
36/386 ... ok
36/387 ... ok
61/388 ... ok
36/389 ... ok
32/390 ... ok
34/391 ... ok
36/392 ... ok
22/393 ... ok
109/394 ... ok
109/395 ... ok
36/396 ... ok
36/398 ... ok
36/400 ... ok
102/401 ... ok
36/402 ... ok
62/403 ... 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


Reply by email is disabled in config/gitlab.yml
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: ...
32/112 ... yes
32/113 ... yes
101/114 ... yes
52/115 ... yes
32/116 ... yes
51/117 ... yes
51/118 ... yes
51/119 ... yes
51/120 ... yes
53/121 ... yes
50/122 ... yes
32/123 ... yes
32/124 ... yes
104/125 ... yes
48/126 ... yes
37/127 ... yes
99/128 ... yes
37/129 ... yes
37/130 ... yes
37/132 ... yes
37/133 ... yes
106/134 ... yes
45/135 ... yes
44/136 ... yes
44/137 ... yes
37/138 ... yes
32/139 ... yes
46/140 ... yes
37/141 ... yes
37/142 ... yes
37/143 ... yes
37/144 ... yes
34/145 ... yes
34/146 ... yes
34/147 ... yes
34/148 ... yes
34/149 ... yes
34/150 ... yes
34/151 ... yes
34/152 ... yes
34/153 ... yes
34/154 ... yes
34/155 ... yes
43/156 ... yes
32/157 ... yes
37/158 ... yes
37/159 ... yes
37/160 ... yes
37/161 ... yes
39/162 ... yes
79/163 ... yes
34/164 ... yes
42/165 ... yes
42/166 ... yes
32/167 ... yes
32/168 ... yes
32/169 ... yes
74/170 ... yes
42/171 ... yes
42/172 ... yes
37/173 ... yes
54/174 ... yes
35/175 ... yes
35/176 ... yes
103/177 ... yes
32/178 ... yes
35/179 ... yes
35/180 ... yes
54/181 ... yes
35/182 ... yes
54/183 ... yes
54/184 ... yes
40/186 ... yes
56/187 ... yes
56/188 ... yes
38/189 ... yes
34/190 ... yes
57/191 ... yes
57/192 ... yes
56/193 ... yes
33/194 ... yes
33/195 ... yes
33/196 ... yes
33/197 ... yes
33/198 ... yes
69/199 ... yes
40/200 ... yes
41/201 ... yes
41/202 ... yes
34/203 ... yes
34/204 ... yes
55/206 ... yes
59/207 ... yes
59/208 ... yes
58/209 ... yes
54/210 ... yes
58/211 ... yes
58/212 ... yes
32/213 ... yes
32/214 ... yes
32/215 ... yes
58/216 ... yes
51/217 ... yes
51/218 ... yes
63/219 ... yes
63/221 ... yes
73/222 ... yes
73/223 ... yes
66/228 ... yes
33/229 ... yes
69/230 ... yes
36/234 ... yes
36/236 ... yes
36/237 ... yes
36/238 ... yes
36/239 ... yes
56/240 ... yes
62/244 ... yes
36/245 ... yes
2/246 ... yes
58/248 ... yes
63/249 ... yes
59/250 ... yes
70/251 ... yes
70/252 ... yes
70/253 ... yes
70/254 ... yes
36/255 ... yes
72/257 ... yes
72/258 ... yes
72/259 ... yes
72/260 ... yes
73/263 ... yes
74/264 ... yes
36/267 ... yes
77/268 ... yes
77/269 ... yes
34/270 ... yes
78/271 ... yes
78/272 ... yes
78/273 ... yes
36/274 ... yes
79/275 ... yes
80/280 ... yes
36/281 ... yes
34/283 ... yes
81/285 ... yes
2/286 ... yes
33/287 ... yes
82/288 ... yes
82/289 ... yes
82/290 ... yes
83/291 ... yes
62/292 ... yes
66/295 ... yes
84/296 ... yes
84/297 ... yes
84/298 ... yes
57/299 ... yes
87/305 ... yes
62/307 ... yes
36/314 ... yes
36/316 ... yes
36/317 ... yes
90/318 ... yes
58/319 ... yes
61/320 ... yes
61/322 ... yes
22/323 ... yes
22/324 ... yes
32/325 ... yes
32/326 ... yes
61/328 ... yes
61/329 ... yes
22/331 ... yes
62/332 ... yes
36/333 ... yes
32/339 ... yes
36/340 ... yes
62/341 ... yes
32/342 ... yes
62/343 ... yes
71/344 ... yes
61/345 ... yes
2/346 ... yes
95/348 ... yes
32/349 ... yes
96/350 ... yes
62/351 ... yes
61/352 ... yes
96/354 ... yes
32/355 ... yes
32/358 ... yes
95/359 ... yes
95/360 ... yes
36/361 ... yes
99/362 ... yes
61/363 ... yes
36/364 ... yes
100/365 ... yes
100/366 ... yes
101/367 ... yes
36/369 ... yes
36/370 ... yes
103/371 ... yes
104/373 ... yes
105/375 ... yes
105/376 ... yes
105/377 ... yes
62/379 ... yes
62/380 ... yes
106/381 ... yes
36/382 ... yes
57/383 ... yes
107/384 ... yes
36/385 ... yes
36/386 ... yes
36/387 ... yes
61/388 ... yes
36/389 ... yes
32/390 ... yes
34/391 ... yes
36/392 ... yes
22/393 ... yes
109/394 ... yes
109/395 ... yes
36/396 ... yes
36/398 ... yes
36/400 ... yes
102/401 ... yes
36/402 ... yes
62/403 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.3.6)
Git version >= 2.9.5 ? ... yes (2.14.3)
Git user has default SSH configuration? ... yes
Active users: ... 15


Checking GitLab ... Finished
Edited by 🤖 GitLab Bot 🤖