Atom feed 500 error after pushing new project with tags

Summary

Creating a project with a bunch of commits and some tags appears to break the Activity Atom feed.

Steps to reproduce

See #247459 (comment 423276176).

Example Project

https://gitlab.com/ancow/atom-500-test

What is the current bug behavior?

Accessing the Atom feed at /dashboard/projects.atom?rss_token=XXX produces an HTTP 500 error.

What is the expected correct behavior?

Atom feed is generated successfully.

Relevant logs and/or screenshots

Started GET "/dashboard/projects.atom" for 10.91.100.1 at 2020-09-10 05:21:49 +0200
Processing by Dashboard::ProjectsController#index as ATOM
Completed 500 Internal Server Error in 599ms (ActiveRecord: 97.6ms | Elasticsearch: 0.0ms | Allocations: 85821)
  
ActionView::Template::Error (No route matches {:action=>"show", :controller=>"projects/commits", :format=>"atom", :id=>nil, :namespace_id=>#<Group id:19 @bu.lsc>, :project_id=>#<Project id:229 bu.lsc/setup>>}, possible unmatched constraints: [:id]):
    4: 
    5: xml.entry do
    6:   xml.id      "tag:#{request.host},#{event.created_at.strftime("%Y-%m-%d")}:#{event.id}"
    7:   xml.link    href: event_feed_url(event)
    8:   xml.title   truncate(event_feed_title(event), length: 80)
    9:   xml.updated event.updated_at.xmlschema
   10: 
  
config/application.rb:321:in `block (4 levels) in <class:Application>'
app/helpers/events_helper.rb:173:in `push_event_feed_url'
app/helpers/events_helper.rb:156:in `event_feed_url'
app/views/events/_event.atom.builder:7
app/views/events/_event.atom.builder:5
app/views/dashboard/projects/index.atom.builder:7
app/controllers/application_controller.rb:134:in `render'
app/controllers/dashboard/projects_controller.rb:24:in `block (2 levels) in index'
app/controllers/dashboard/projects_controller.rb:18:in `index'
app/controllers/application_controller.rb:491:in `set_current_admin'
lib/gitlab/session.rb:11:in `with_session'
app/controllers/application_controller.rb:482:in `set_session_storage'
lib/gitlab/i18n.rb:55:in `with_locale'
lib/gitlab/i18n.rb:61:in `with_user_locale'
app/controllers/application_controller.rb:476:in `set_locale'
lib/gitlab/error_tracking.rb:50:in `with_context'
app/controllers/application_controller.rb:541:in `sentry_context'
app/controllers/application_controller.rb:469:in `block in set_current_context'
lib/gitlab/application_context.rb:52:in `block in use'
lib/gitlab/application_context.rb:52:in `use'
lib/gitlab/application_context.rb:20:in `with_context'
app/controllers/application_controller.rb:462:in `set_current_context'
lib/gitlab/request_profiler/middleware.rb:17:in `call'
lib/gitlab/middleware/go.rb:20:in `call'
lib/gitlab/etag_caching/middleware.rb:13:in `call'
lib/gitlab/middleware/multipart.rb:140:in `call'
lib/gitlab/middleware/read_only/controller.rb:51:in `call'
lib/gitlab/middleware/read_only.rb:18:in `call'
lib/gitlab/middleware/same_site_cookies.rb:27:in `call'
lib/gitlab/middleware/basic_health_check.rb:25:in `call'
lib/gitlab/middleware/handle_ip_spoof_attack_error.rb:25:in `call'
lib/gitlab/middleware/request_context.rb:23:in `call'
config/initializers/fix_local_cache_middleware.rb:9:in `call'
lib/gitlab/metrics/requests_rack_middleware.rb:60:in `call'
lib/gitlab/middleware/release_env.rb:12:in `call'

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

Note: in the output below I changed the hostname.

System information
System:         Debian 10
Current User:   git
Using RVM:      no
Ruby Version:   2.6.6p146
Gem Version:    2.7.10
Bundler Version:1.17.3
Rake Version:   12.3.3
Redis Version:  5.0.9
Git Version:    2.27.0
Sidekiq Version:5.2.9
Go Version:     unknown

GitLab information
Version:        13.2.9
Revision:       d43bc5ce99e
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     PostgreSQL
DB Version:     11.7
URL:            http://gitlab.example.com
HTTP Clone URL: http://gitlab.example.com/some-group/some-project.git
SSH Clone URL:  git@gitlab.example.com:some-group/some-project.git
Using LDAP:     yes
Using Omniauth: yes
Omniauth Providers: 

GitLab Shell
Version:        13.3.0
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 >= 13.3.0 ? ... OK (13.3.0)
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 93 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: ...
2/1 ... yes
2/2 ... yes
3/4 ... yes
6/5 ... yes
2/6 ... yes
2/7 ... yes
6/8 ... yes
6/9 ... yes
6/10 ... yes
6/11 ... yes
6/12 ... yes
6/13 ... yes
6/14 ... yes
6/15 ... yes
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11/17 ... yes
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2/22 ... yes
27/25 ... yes
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33/60 ... yes
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3/65 ... yes
42/66 ... yes
29/67 ... yes
15/68 ... yes
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30/81 ... yes
56/82 ... yes
15/84 ... yes
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51/87 ... yes
23/88 ... yes
15/89 ... yes
15/91 ... yes
56/92 ... yes
3/93 ... yes
40/94 ... yes
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59/97 ... yes
40/98 ... yes
33/99 ... yes
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40/102 ... yes
63/103 ... yes
63/104 ... yes
56/105 ... yes
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56/111 ... yes
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40/117 ... yes
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65/119 ... yes
2/120 ... yes
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6/135 ... yes
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33/137 ... yes
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3/145 ... yes
56/150 ... yes
40/151 ... yes
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40/156 ... yes
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7/168 ... yes
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22/179 ... yes
56/182 ... yes
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56/199 ... yes
6/200 ... yes
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44/204 ... yes
22/205 ... yes
6/206 ... yes
6/207 ... yes
6/208 ... yes
9/209 ... yes
14/210 ... yes
3/211 ... yes
11/212 ... yes
2/213 ... yes
56/214 ... yes
56/215 ... yes
6/216 ... yes
56/217 ... yes
79/218 ... yes
87/219 ... yes
75/220 ... yes
79/221 ... yes
8/222 ... yes
8/223 ... yes
8/224 ... yes
8/225 ... yes
79/226 ... yes
19/229 ... yes
Redis version >= 4.0.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.6)
Git version >= 2.22.0 ? ... yes (2.27.0)
Git user has default SSH configuration? ... yes
Active users: ... 44
Is authorized keys file accessible? ... yes
GitLab configured to store new projects in hashed storage? ... yes
All projects are in hashed storage? ... yes
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished

Possible fixes

Not so much a fix as a workaround, but exporting and re-importing the project seems to have resolved the issue.