On that note, does git as a protocol even have a clean mechanism for redacting history like this? If someone were to press this to the logical extreme, how could a developer most cleanly excise violating history from a repo using current tooling?
There is a way, its not very clean, git filter-branch and you will have to force push all branches, which is fun with large teams.
Unfortunately in larger repos with long histories its extremely slow, and uses a lot of IO. I used it previously to clean up large binaries that were included early on in a repo's history, making it take up way more space than needed.
I assume you would have to revert to the parent of the offending commit, cherry-pick the non-offending code, commit, then rebase the entire master branch on that new commit.
Then you'd have to repeat the process for all forks and branches. It'd be a huge pain, but I think it's doable.
I've never tried something like this, though, so there might be some complications.
