Contaminated Remote master branch or Anti-Cherry-Pick

Question

I have a situation where the remote repository has some "bad" commits. e.g.

... o ---- C ---- A ---- B  origin/master 

Where A is bad (but B is good) I want the remote to become...

... o ---- C ---- B  origin/master 
                   \
                    A  origin/dev 

It is not obvious to me how to do this.

In the case where a rebase is inappropriate a different result is needed.

... o ---- C ---- A ---- B ---- ~A origin/master 
                          \
                           -  origin/dev 

This results in a dev branch containing the A commit and the master not containing the A commit. The revised question is: How to do an anti-cherry-pick? So rather than generating a patch which changes the repository from state C to A apply a patch which changes B to A.

Answer 1

Pull so that you have the same repository locally.

Use git rebase --interactive (see this rundown if you are unfamiliar with interactive rebase) to reorder the A and B commits, so that you now have

... o ---- o ---- B ---- A  master 

Checkout a new branch dev from that spot, so you get

... o ---- o ---- B ---- A  master, dev

Switch to the master branch, do a git reset --hard HEAD^ to rewind that branch one commit. You now have

... o ---- o ---- B  master 
                   \
                    A  dev 

Now git push --force --all and you should be golden. (You need --force because you are rewriting history in the remote repository, which is dangerous and not recommended if other developers have already pulled from it.)