How do you remove a branch and all of its history locally and remotely?

Question

I have a git branch I need to nuke all traces of. I think I need something like

git filter-branch --index-filter 'git -D <branch>' --tag-name-filter cat -- --all

or maybe

git filter-branch --index-filter 'git rm --cached *' --tag-name-filter cat -- <branch>

Then I would

git push -f origin :<branch>

I'm hesitant to try them without knowing for sure what they'll do or if they'll work.

Answer 1

Let's say you want to nuke evilbranch.

You say you want to delete all of a branch's history. This technically includes the initial commit, which is probably more commits then you want. So first, identify which commit you consider to be the first commit of that branch. Let's say it's 666bad. Now we need to find all references to it. Run

git branch -a --contains 666bad
git tag --contains 666bad

Now delete them all. You can either use git commands, or just go into .git/refs.

Do this on every computer that might have the file.

Make sure you are not in detached head.

Now we can kill all the commits, and therefore all the code, that is no longer referenceable (from this gitHub link):

git for-each-ref --format='delete %(refname)' refs/original | git update-ref --stdin
git reflog expire --expire=now --all
git gc --prune=now

Again, this should be done on each computer.

Finally, use this on each computer.

Note: 666bad is the first commit after evilbranch split from wherever it came from, i.e., the first commit that is only evilbranch.