### Summary Certain payloads for merge request events (i.e. "rebase" on MR) will give an empty array for `.changes.labels.previous` regardless of what the previous labels were. We have a bot that does things (not idempotent) when a certain label is added. We'd like not to keep state so we check if the label was already present in `.changes.labels.previous` before performing this action. Problem is that this field is not alway correct and often shows empty. ### Steps to reproduce * Create a merge request * add a label -> payload is correct * rebase merge request -> payload is not correct, `.changes.labels.previous` is `[]` ### What is the current *bug* behavior? Certain payloads for merge request events will always give an empty array for `.changes.labels.previous`. ### What is the expected *correct* behavior? Show whatever were the previous labels in `.changes.labels.previous`. #### Results of GitLab environment info <details> <summary>Expand for output related to GitLab environment info</summary> <pre> steven@gitlab:~$ sudo gitlab-rake gitlab:env:info System information System: Ubuntu 16.04 Proxy: no 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: 10.7.0-ee Revision: 53adfd5 Directory: /opt/gitlab/embedded/service/gitlab-rails DB Adapter: postgresql DB Version: 9.6.8 URL: https://gitlab.silverfin.com HTTP Clone URL: https://gitlab.silverfin.com/some-group/some-project.git SSH Clone URL: git@gitlab.silverfin.com:some-group/some-project.git Elasticsearch: yes Geo: no Using LDAP: no Using Omniauth: yes Omniauth Providers: google_oauth2, github 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> steven@gitlab:~$ sudo gitlab-rake gitlab:check SANITIZE=true 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: ... 10/10 ... ok 10/11 ... ok 10/12 ... ok 10/13 ... ok 9/20 ... ok 11/24 ... ok 9/28 ... ok 10/30 ... ok 10/37 ... ok 9/42 ... ok 10/43 ... ok 11/44 ... ok 11/52 ... ok 9/55 ... ok 9/57 ... ok 30/58 ... ok 3/59 ... ok 3/60 ... ok 3/61 ... ok 3/62 ... ok 3/63 ... ok 3/65 ... ok 3/66 ... ok 3/67 ... ok 3/68 ... ok 3/69 ... ok 3/70 ... ok 3/71 ... ok 3/72 ... ok 3/73 ... ok 3/74 ... ok 3/75 ... ok 3/76 ... ok 3/77 ... ok 3/78 ... ok 3/80 ... ok 3/81 ... ok 3/82 ... ok 3/83 ... ok 3/84 ... ok 3/85 ... ok 3/86 ... ok 3/87 ... ok 3/88 ... ok 3/89 ... ok 3/90 ... ok 3/91 ... ok 3/93 ... ok 3/94 ... repository is empty 3/95 ... ok 3/96 ... ok 3/98 ... ok 3/103 ... ok 3/104 ... ok 3/105 ... ok 3/107 ... ok 3/108 ... ok 3/113 ... 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: ... 10/10 ... yes 10/11 ... yes 10/12 ... yes 10/13 ... yes 9/20 ... yes 11/24 ... yes 9/28 ... yes 10/30 ... yes 10/37 ... yes 9/42 ... yes 10/43 ... yes 11/44 ... yes 11/52 ... yes 9/55 ... yes 9/57 ... yes 30/58 ... yes 3/59 ... yes 3/60 ... yes 3/61 ... yes 3/62 ... yes 3/63 ... yes 3/65 ... yes 3/66 ... yes 3/67 ... yes 3/68 ... yes 3/69 ... yes 3/70 ... yes 3/71 ... yes 3/72 ... yes 3/73 ... yes 3/74 ... yes 3/75 ... yes 3/76 ... yes 3/77 ... yes 3/78 ... yes 3/80 ... yes 3/81 ... yes 3/82 ... yes 3/83 ... yes 3/84 ... yes 3/85 ... yes 3/86 ... yes 3/87 ... yes 3/88 ... yes 3/89 ... yes 3/90 ... yes 3/91 ... yes 3/93 ... yes 3/94 ... yes 3/95 ... yes 3/96 ... yes 3/98 ... yes 3/103 ... yes 3/104 ... yes 3/105 ... yes 3/107 ... yes 3/108 ... yes 3/113 ... 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: ... 31 Elasticsearch version 5.1 - 5.5? ... no (5.6.9) For more information see: doc/integration/elastcsearch.md Checking GitLab ... Finished </pre> </details> ### Possible fixes (If you can, link to the line of code that might be responsible for the problem)