How to recover from the "git push -f origin HEAD^:master" command?

I was searching for a way to remove my last GitHub commit and found this command on:

How can I remove a commit on GitHub?

It worked. The problem is that I accidentally did it to the wrong repository.

I read in comments that commit is not really deleted, but

"...this only moves the branch pointer."

How can I recover from this command and revert to the last commit?

Solution

GitHub has an hidden reflog: the GitHub Events API.

See "Does github remember commit IDs?"

By curling the https://api.github.com/repos/<user>/<repo>/events, and looking for push events, you can find the commit pushed to master before your own, and push again that commit, provided you had a local clone of that repo.