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This article explains the revert command when a merge conflict occurs git merge. We will also take a quick look at how to undo a git merge that was successful and has been pushed to a remote repository.

Recovering a conflicting Git merge

In this section, we will use an example as described below.

Our repository has master and feature branches. We will edit the README.md file in both branches so that merging master into feature will cause a conflict.

After running git mergethe command, we should get something similar.

To undo such a merge, we can run git merge --abortthe command as shown below.

$ git merge --abort

This command will reset our repository to its previous state before the merge. It should even recover uncommitted changes, although unreliably.

Also, only a newbie would merge a branch with uncommitted changes.

We can also use git reset --mergethe command, which has the git merge --abortsame effect as the command.

$ git reset --merge

Another handy command is git reset --hard. It will unmerge as well as merge in any changes introduced to your working copy.

What if we want to undo a successful merge?

First, we need the commit hash of the merge. We can run the git log --oneline command to list the commits in our repository.

We will then copy the hash of the merge commit as shown below.

After the merge commit, we will use git resetthe -m command with the commit hash. In simple terms, the commit is at HEAD@{1}.

$ git reset --hard c315395
HEAD is now at c315395 Trial2

Alternatively, we can run git resetthe command as shown below.

$ git reset --hard HEAD~1

This will rollback our repository by a single commit.

In the case where we pushed the merge to the remote repository, how can we recover the same content?

If we have already pushed the changes, we have to create a commit to revert the merged changes and push them to the remote repository as shown below.

$ git revert -m 1 08396d4

This will revert the changes introduced by the merge. We have already used the git revert command with the commit hash of the merge commit.

Now we can push our changes to the remote to revert the merge.

In short, Git allows you to unmerge when conflicts arise. The git reset --mergeand git merge --abortcommands come in handy in situations like this.

If our merge was successful and we have pushed our changes to the remote, we will have to create a new commit to undo the changes introduced by the merge.