Git repository corrupt; "rebuild without cache" doesn't fix


My build is failing at this step:

$ [[ ! -s "$(git rev-parse --git-dir)/shallow" ]] || git fetch --unshallow
returned exit code 128

fatal: error in object: unshallow fe2f1d9afaaaaf3a836cfe261d5b2ed2a316320f
Action failed: [[ ! -s "$(git rev-parse --git-dir)/shallow" ]] || git fetch --unshallow

We were previously on the paid plan and when this happened before it was quickly resolved by sending a message through Intercom. I was told that there was no UI to take care of it myself and had to be resolved by contacting support. Now that time has passed and I’m on the free plan… how do I fix this? Intercom is no longer available.


Update. I found someone else with the same problem and no response:

Git errors failing the build when deploying to Heroku