gitlab-cookbooks dirties the cache on every run
I've seen build times go up short of 60 minutes because gitlab-cookbooks
keeps dirtying the cache:
[Software: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Could not restore from cache
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Starting build
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | $ mkdir -p /opt/gitlab/embedded/cookbooks
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Execute: `mkdir -p /opt/gitlab/embedded/cookbooks': 0.0283s
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | sync `./' to `/opt/gitlab/embedded/cookbooks/': 0.1363s
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Rendering `/builds/gitlab/omnibus-gitlab/config/templates/gitlab-cookbooks/dna.json.erb' to `/opt/gitlab/embedded/cookbooks/dna.json'
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Render erb `dna.json.erb': 0.0006s
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Build gitlab-cookbooks: 0.1718s
[Builder: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Finished build
[Software: gitlab-cookbooks] I | 2019-09-03T02:36:43+00:00 | Dirtied the cache
[Software: acme-client] I | 2019-09-03T02:36:43+00:00 | Building because `gitlab-cookbooks' dirtied the cache
This is reproducible on nearly every recent build, including the latest master https://dev.gitlab.org/gitlab/omnibus-gitlab/-/jobs/5247101 (internal link).
Was there a recent change that caused this? How do we get the build back down to 20 minutes?