`package-and-qa` can fail when new commits are pushed since it fetches Git repo with a depth of 1
Job #302154422 failed for e12a355c:
Fetching changes with git depth set to 1...
Initialized empty Git repository in /builds/gitlab-org/gitlab/.git/
Created fresh repository.
From https://gitlab.com/gitlab-org/gitlab
* [new branch] master -> origin/master
Checking out e12a355c as master...
fatal: reference is not a tree: e12a355c0fbeaa6b5695eb925fa29bb2ba3ff82e
Fetching changes with git depth set to 1...
Reinitialized existing Git repository in /builds/gitlab-org/gitlab/.git/
Checking out e12a355c as master...
fatal: reference is not a tree: e12a355c0fbeaa6b5695eb925fa29bb2ba3ff82e
Fetching changes with git depth set to 1...
Reinitialized existing Git repository in /builds/gitlab-org/gitlab/.git/
Checking out e12a355c as master...
fatal: reference is not a tree: e12a355c0fbeaa6b5695eb925fa29bb2ba3ff82e
The simplest fix is to fetch the repo with the default depth of 20.