Error 500 for /api/v4/projects/ID/services/jira - NoMethodError (undefined method `slice' for nil:NilClass)

Summary

Can't get Jira service of project

Steps to reproduce

GET https://HOSTNAME/api/v4/projects/PROJECTID/services/jira

The error disappears after PUT https://HOSTNAME/api/v4/projects/PROJECTID/services/jira or saving the service with https://HOSTNAME/PATH_WITH_NAMESPACE/-/settings/integrations

GET https://HOSTNAME/api/v4/projects/PROJECTID/services/bamboo does not have this problem

What is the current bug behavior?

Returns {"message":"500 Internal Server Error"}

What is the expected correct behavior?

Output from https://docs.gitlab.com/ee/api/services.html#get-jira-service-settings or better error message

Relevant logs and/or screenshots

production.log:

NoMethodError (undefined method `slice' for nil:NilClass):
  /opt/gitlab/embedded/service/gitlab-rails/lib/api/entities.rb:1067:in `block in <class:ProjectService>'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/entity.rb:496:in `instance_exec'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/entity.rb:496:in `exec_with_object'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/block_exposure.rb:10:in `value'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/base.rb:82:in `valid_value'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/base.rb:66:in `serializable_value'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:41:in `block in serializable_value'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:120:in `block (2 levels) in map_entity_exposures'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/base.rb:116:in `block in with_attr_path'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/options.rb:90:in `with_attr_path'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/base.rb:115:in `with_attr_path'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:119:in `block in map_entity_exposures'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:118:in `each'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:118:in `each_with_object'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:118:in `map_entity_exposures'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/exposure/nesting_exposure.rb:40:in `serializable_value'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/entity.rb:489:in `serializable_hash'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-entity-0.7.1/lib/grape_entity/entity.rb:520:in `to_json'
  /opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/grape-1.1.0/lib/grape/formatter/json.rb:6:in `call'
...

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Debian 9.11
Proxy:		no
Current User:	git
Using RVM:	no
Ruby Version:	2.6.3p62
Gem Version:	2.7.9
Bundler Version:1.17.3
Rake Version:	12.3.3
Redis Version:	3.2.12
Git Version:	2.22.0
Sidekiq Version:5.2.7
Go Version:	unknown
GitLab information
Version:	12.4.0-ee
Revision:	572e09f5e8f
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	PostgreSQL
DB Version:	10.9
URL:		https://git
HTTP Clone URL:	https://git/some-group/some-project.git
SSH Clone URL:	git@git:some-group/some-project.git
Elasticsearch:	no
Geo:		no
Using LDAP:	yes
Using Omniauth:	yes
Omniauth Providers:
GitLab Shell
Version:	10.2.0
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories GitLab Shell path: /opt/gitlab/embedded/service/gitlab-shell Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 10.2.0 ? ... OK (10.2.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Reply by email is disabled in config/gitlab.yml
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... Server: ldapmain
LDAP authentication... Success
LDAP users with access to your GitLab server (only showing the first 100 results)
User output sanitized. Found 32 users of 100 limit.
Checking LDAP ... Finished
Checking GitLab App ...
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: ...
5/1 ... yes
5/2 ... yes
5/3 ... yes
5/4 ... yes
5/5 ... yes
13/6 ... yes
5/7 ... yes
5/8 ... yes
5/9 ... yes
5/10 ... yes
5/11 ... yes
11/12 ... yes
11/13 ... yes
11/14 ... yes
5/15 ... yes
5/16 ... yes
5/17 ... yes
5/18 ... yes
5/19 ... yes
5/20 ... yes
5/21 ... yes
5/22 ... yes
5/23 ... yes
3/24 ... yes
22/27 ... yes
5/28 ... yes
5/29 ... yes
5/30 ... yes
22/31 ... yes
22/32 ... yes
5/33 ... yes
39/34 ... yes
10/35 ... yes
3/36 ... yes
6/37 ... yes
3/38 ... yes
39/39 ... yes
22/40 ... yes
3/41 ... yes
3/42 ... yes
27/43 ... yes
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27/45 ... yes
39/46 ... yes
39/47 ... yes
17/70 ... yes
3/71 ... yes
6/72 ... yes
3/75 ... yes
3/76 ... yes
27/77 ... yes
27/78 ... yes
27/79 ... yes
12/80 ... yes
12/82 ... yes
61/85 ... yes
39/86 ... yes
27/87 ... yes
39/88 ... yes
11/89 ... yes
27/100 ... yes
30/102 ... yes
27/103 ... yes
3/107 ... yes
27/108 ... yes
27/109 ... yes
6/110 ... yes
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25/114 ... yes
27/115 ... yes
14/116 ... yes
55/118 ... yes
43/119 ... yes
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43/125 ... yes
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44/128 ... yes
27/129 ... yes
55/132 ... yes
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43/134 ... yes
27/135 ... yes
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44/137 ... yes
42/138 ... yes
6/139 ... yes
48/140 ... yes
27/141 ... yes
10/144 ... yes
42/145 ... yes
4/146 ... yes
3/147 ... yes
6/149 ... yes
43/150 ... yes
10/151 ... yes
55/152 ... yes
6/153 ... yes
10/154 ... yes
13/155 ... yes
27/157 ... yes
39/158 ... yes
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39/160 ... yes
39/161 ... yes
27/162 ... yes
52/163 ... yes
42/166 ... yes
6/168 ... yes
42/169 ... yes
10/170 ... yes
52/171 ... yes
10/172 ... yes
52/173 ... yes
27/174 ... yes
52/175 ... yes
13/176 ... yes
6/177 ... yes
14/180 ... yes
54/182 ... yes
14/183 ... yes
14/184 ... yes
42/185 ... yes
13/186 ... yes
14/187 ... yes
56/188 ... yes
14/189 ... yes
7/190 ... yes
6/194 ... yes
59/200 ... yes
39/202 ... yes
39/203 ... yes
39/204 ... yes
60/205 ... yes
60/206 ... yes
60/207 ... yes
39/210 ... yes
39/211 ... yes
58/212 ... yes
39/215 ... yes
39/217 ... yes
39/219 ... yes
39/220 ... yes
39/221 ... yes
5/222 ... yes
56/223 ... yes
7/224 ... yes
6/225 ... yes
9/227 ... yes
15/228 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.3)
Git version >= 2.22.0 ? ... yes (2.22.0)
Git user has default SSH configuration? ... yes
Active users: ... 33
Is authorized keys file accessible? ... yes
Elasticsearch version 5.6 - 6.x? ... skipped (elasticsearch is disabled)
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished