Revert and Unmerge

git revert and Unmerging Changes

After this page you can undo a published commit by adding a new commit, including a merge.

Revert writes history forward

cd ~/desk/desk-api
git switch main
git revert HEAD --no-edit
git log --oneline -3

The bad commit is still in the graph. A new commit applies the inverse patch. Shared clones can fast-forward. This is the safe undo on main.

 reset --hard HEAD~1     (local only)     A ← B            main
                                          C still in reflog

 revert HEAD             (shared)         A ← B ← C ← R    main
                                          R undoes C; C remains

--no-edit keeps Git’s default message (Revert "…"). Edit with git revert HEAD if you need a fix: subject.

Several commits

git revert --no-edit HEAD~2..HEAD

Reverts newest first (the range is exclusive on the left). Conflicts: git add and git revert --continue, or git revert --abort.

Revert a merge commit

A merge has two parents. Git needs to know which parent is “the mainline” to diff against:

git revert -m 1 <merge-hash>

-m 1 means “keep first parent’s tree; undo what the merged branch brought in.” -m 2 is the other parent (almost never what you want on main).

After reverting a merge, Git considers that feature’s commits already merged. Cherry-picking them back later can no-op. To re-land the feature, revert the revert, or rebase the feature into new hashes.

Revert vs reset vs restore

Goal	Command	History
Throw away uncommitted edits	git restore	Unchanged
Replace last unpublished commit	git commit --amend / reset	Rewritten
Undo a published commit	git revert	New commit

git reset --hard on shared main is a force-push incident. Revert instead.

Un-merge without -m

If the merge was never pushed and is HEAD:

git reset --hard HEAD~1

That moves main to first parent and drops the merge commit from the branch name. Only on a lab clone or an unpublished branch. Chapter 7 is reset in full. The merge commit stays in the reflog (chapter 17) until it expires.