How to use bfg-repo-cleaner after Git rebase on non-bare repo?

Question

Overview

I have Git repo which serves as an archive for a number of configs sourced from elsewhere:

• 200 dirs
• 100 files per dir
• 10K plain text per file
• ~1000 commits per day, usually < 10 lines edited
• 1 branch
• 1 user handles all commits
• all other view repo on read-only basis

Before anyone suggest I try breaking up this repo into smaller ones, that's not an option because customers.

The repo contains ~2 years worth of data but our customers only need last 90 days.

Process

I have successfully grafted the root onto a commit 90 days ago using the method described here :

• git checkout -b newroot xyz_90_days_old_rev
• git reset abc_original_root_rev
• git add .
• git commit --amend -m 'purge history'
• git checkout master
• git rebase --onto newroot xyz_90_days_old_rev

The problem is using git-filter-branch cleanup afterwards - it takes > 24 hours which is unacceptable downtime to users.

I would like to try bfg-repo-cleaner instead, but it's not clear to me:

• does it support this use case?
• does it work on a non-bare repo?

PS : I am now aware that git checkout --orphan would have been slightly more elegant, but it doesn't really change the problem that BFG requires the repo be bare while checkout requires it not be bare

Answer 1

Don't bother rewriting the repo. If someone only needs the last 90 days, run a script to estimate the required depth and have them create a shallow clone with --depth <depth> .

BFG should be run on a mirror/bare clone.