Overwrote master with another branch completely when trying to merge, how to revert it?

Question

I wanted to merge two branches into one, however instead I overwrote it.

On github desktop I went toolbar branch -> "Merge into current branch" on master, chose branch A then pushed it, and now it's as if branch A has been copied over into master without any trace at all of the previous master branch.

How do I revert it? There's no commit history of the merge at all & cant find anything about it.

Answer 1

Run git reflog master in a terminal, you will see a history of the previous states of your master branch.

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To revert to a target commit :

from a clean worktree (e.g: git status indicates that there are no modified files and nothing to commit), you can use git reset --hard:

# switch to your master branch:
git checkout master

# move it to its previous state:
git reset --hard <sha>