<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "regression" or "bug" label. For the Community Edition issue tracker: - https://gitlab.com/gitlab-org/gitlab-ce/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab-ce/issues?label_name%5B%5D=bug For the Enterprise Edition issue tracker: - https://gitlab.com/gitlab-org/gitlab-ee/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab-ee/issues?label_name%5B%5D=bug and verify the issue you're about to submit isn't a duplicate. ---> ### Summary When some comments on image in MR, no email notification is sent out but error in sidekiq. Initially reported by customer https://gitlab.my.salesforce.com/00161000017upDb ### Steps to reproduce * Create project * Create feature branch * Create a commit with an image * Make MR * Make sure you have email notifications turned on * Get someone else to make a comment on the image (hover over the image and click to make a comment on the image) ### Example Project N/A ### What is the current *bug* behavior? Email not sent and dead job in sidekiq like below.  ### What is the expected *correct* behavior? No error in sidekiq and email delivered. ### Relevant logs and/or screenshots ``` 2018-06-04_06:45:18.39805 2018-06-04T06:45:18.397Z 4016 TID-ou1yui1s4 ActionMailer::DeliveryJob JID-01b2e325f2b0500a9006cb41 INFO: fail: 0.363 sec 2018-06-04_06:45:18.39813 2018-06-04T06:45:18.398Z 4016 TID-ou1yui1s4 WARN: {"context":"Job raised exception","job":{"class":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper","wrapped":"ActionMailer::DeliveryJob","queue":"mailers","args":[{"job_class":"ActionMailer::DeliveryJob","job_id":"7bae6010-e830-4aa8-ba10-3c64b70d3c0b","queue_name":"mailers","arguments":["Notify","note_merge_request_email","deliver_now",1,889],"locale":"en"}],"retry":3,"jid":"01b2e325f2b0500a9006cb41","created_at":1528094718.0334277,"enqueued_at":1528094718.033826},"jobstr":"{\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::DeliveryJob\",\"queue\":\"mailers\",\"args\":[{\"job_class\":\"ActionMailer::DeliveryJob\",\"job_id\":\"7bae6010-e830-4aa8-ba10-3c64b70d3c0b\",\"queue_name\":\"mailers\",\"arguments\":[\"Notify\",\"note_merge_request_email\",\"deliver_now\",1,889],\"locale\":\"en\"}],\"retry\":3,\"jid\":\"01b2e325f2b0500a9006cb41\",\"created_at\":1528094718.0334277,\"enqueued_at\":1528094718.033826}"} 2018-06-04_06:45:18.39815 2018-06-04T06:45:18.398Z 4016 TID-ou1yui1s4 WARN: ActionView::Template::Error: undefined method `index' for nil:NilClass 2018-06-04_06:45:18.39820 2018-06-04T06:45:18.398Z 4016 TID-ou1yui1s4 WARN: /opt/gitlab/embedded/service/gitlab-rails/app/models/concerns/discussion_on_diff.rb:44:in `truncated_diff_lines' 2018-06-04_06:45:18.39820 /opt/gitlab/embedded/service/gitlab-rails/app/views/notify/_note_email.text.erb:15:in `_app_views_notify__note_email_text_erb___3953341642096983487_70062052453220' 2018-06-04_06:45:18.39820 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/template.rb:145:in `block in render' 2018-06-04_06:45:18.39821 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb:166:in `instrument' 2018-06-04_06:45:18.39821 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/template.rb:333:in `instrument' 2018-06-04_06:45:18.39821 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/template.rb:143:in `render' 2018-06-04_06:45:18.39822 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/renderer/partial_renderer.rb:339:in `render_partial' 2018-06-04_06:45:18.39822 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/renderer/partial_renderer.rb:310:in `block in render' 2018-06-04_06:45:18.39823 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument' 2018-06-04_06:45:18.39823 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb:166:in `instrument' 2018-06-04_06:45:18.39823 /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionview-4.2.10/lib/action_view/renderer/abstract_renderer.rb:39:in `instrument' <snipped> ``` ### Output of checks (If you are reporting a bug on GitLab.com, write: This bug happens on GitLab.com) #### Results of GitLab environment info <details> <summary>Expand for output related to GitLab environment info</summary> <pre> System information System: Ubuntu 14.04 Proxy: no Current User: git Using RVM: no Ruby Version: 2.3.7p456 Gem Version: 2.6.14 Bundler Version:1.13.7 Rake Version: 12.3.1 Redis Version: 3.2.11 Git Version: 2.16.4 Sidekiq Version:5.0.5 Go Version: unknown GitLab information Version: 10.8.3-ee Revision: 3e7879a Directory: /opt/gitlab/embedded/service/gitlab-rails DB Adapter: postgresql DB Version: 9.6.8 URL: https://gitlab.ee HTTP Clone URL: https://gitlab.ee/some-group/some-project.git SSH Clone URL: git@gitlab.ee:some-group/some-project.git Elasticsearch: no Geo: no Using LDAP: yes Using Omniauth: yes Omniauth Providers: github, gitlab, oauth2_generic GitLab Shell Version: 7.1.2 Repository storage paths: - default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git </pre> </details> #### Results of GitLab application Check <details> <summary>Expand for output related to the GitLab application check</summary> <pre> Checking GitLab Shell ... GitLab Shell version >= 7.1.2 ? ... OK (7.1.2) 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: ... 1/14 ... ok 1/17 ... ok 1/18 ... ok 1/61 ... ok 39/64 ... ok 1/65 ... ok 1/66 ... ok 1/68 ... ok 42/73 ... ok 25/76 ... ok 42/78 ... ok 42/79 ... ok 1/80 ... ok 25/81 ... repository is empty 42/82 ... ok 1/83 ... ok 42/85 ... ok 42/86 ... ok 51/87 ... ok 42/88 ... ok 42/89 ... repository is empty 42/90 ... ok 25/91 ... ok 1/94 ... ok 1/95 ... ok 42/96 ... ok 40/97 ... repository is empty 1/98 ... ok 1/99 ... ok 57/104 ... ok 1/109 ... ok 25/111 ... ok 1/112 ... ok 1/113 ... ok 25/116 ... ok 74/118 ... ok 70/119 ... ok 1/121 ... ok 74/123 ... ok 39/124 ... ok 39/125 ... ok 39/127 ... ok 1/128 ... ok 1/129 ... 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? ... yes Init.d configured correctly? ... skipped MailRoom running? ... skipped Checking Reply by email ... Finished Checking LDAP ... Server: ldapmain LDAP authentication... Success LDAP users with access to your GitLab server (only showing the first 100 results) DN: cn=john doe doe,ou=people,dc=example,dc=org uid: john DN: cn=mary jane jane,ou=people,dc=example,dc=org uid: mary DN: cn=ldapadmin,ou=people,dc=example,dc=org uid: ldapadmin DN: cn=nadmin,ou=people,dc=example,dc=org uid: nadmin DN: cn=may june,ou=people,dc=example,dc=org uid: mjune 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: ... 1/14 ... yes 1/17 ... yes 1/18 ... yes 1/61 ... yes 39/64 ... yes 1/65 ... yes 1/66 ... yes 1/68 ... yes 42/73 ... yes 25/76 ... yes 42/78 ... yes 42/79 ... yes 1/80 ... yes 25/81 ... yes 42/82 ... yes 1/83 ... yes 42/85 ... yes 42/86 ... yes 51/87 ... yes 42/88 ... yes 42/89 ... yes 42/90 ... yes 25/91 ... yes 1/94 ... yes 1/95 ... yes 42/96 ... yes 40/97 ... yes 1/98 ... yes 1/99 ... yes 57/104 ... yes 1/109 ... yes 25/111 ... yes 1/112 ... yes 1/113 ... yes 25/116 ... yes 74/118 ... yes 70/119 ... yes 1/121 ... yes 74/123 ... yes 39/124 ... yes 39/125 ... yes 39/127 ... yes 1/128 ... yes 1/129 ... yes Redis version >= 2.8.0? ... yes Ruby version >= 2.3.5 ? ... yes (2.3.7) Git version >= 2.9.5 ? ... yes (2.16.4) Git user has default SSH configuration? ... no Try fixing it: mkdir ~/gitlab-check-backup-1528096145 sudo mv /var/opt/gitlab/.ssh/id_rsa.pub ~/gitlab-check-backup-1528096145 sudo mv /var/opt/gitlab/.ssh/id_rsa ~/gitlab-check-backup-1528096145 For more information see: doc/ssh/README.md in section "SSH on the GitLab server" Please fix the error above and rerun the checks. Active users: ... 10 Elasticsearch version 5.1 - 5.5? ... skipped (elasticsearch is disabled) Checking GitLab ... Finished </pre> </details> ### Possible fixes (If you can, link to the line of code that might be responsible for the problem)