Use custom version of Git for GitLab.com
Problem to solve
There are patches to Git that we may want to apply before they are released in Git, or patches that we are developing but want to observe in production before pushing them upstream. Today, we have no way of using a custom version of Git on GitLab.com
Further details
Some patches may be higher risk than others, so in the future we may want to bundle multiple versions of Git so that we can quickly roll back or partially deploy a new version. But this can be a later iteration.
Proposal
When releasing GitLab, allow bundling a custom version of Git that is patched.
We can verify this by shipping a low risk modification that improves packfile reuse output: https://gitlab.com/jramsay/git/commit/2acbd22ded110ca02ea2d7b8a57c250d2aa0cf83