undo-op

undo-op

Almost every history-changing operation is reversible because git records where each ref pointed before it moved, in the reflog. Undoing means finding the entry just before the operation and moving the branch back to it.

Steps

1. Inspect recent moves: git reflog (or git reflog show [branch]). Each line shows a HEAD@{N} position and the operation that produced it (rebase, commit --amend, reset, merge, …).
2. Identify the entry that describes the operation the user wants to undo, then look one entry older — that's the state to return to. Confirm by inspecting it: git log --oneline HEAD@{N} and/or git show HEAD@{N}.
3. Show the user that state and confirm it's the outcome they expect before changing anything — the next step is destructive to the current tip.
4. Restore: git reset --hard HEAD@{N} (run on the affected branch). The branch now points where it did before the operation.

Why the reflog, not git revert

git revert adds a new commit that inverts a change — appropriate for undoing a published commit. Here the goal is to rewind local history as if the operation never happened, which reset --hard to a reflog position does cleanly. Because reflog entries persist for a while, even a "lost" commit after a bad rebase is usually still recoverable this way.

Caution: reset --hard discards uncommitted changes. If there are any, stash them first with git stash (-u to include untracked files), then git stash pop after the reset.