Question
Answer and Explanation
Reverting a merge commit in Git can be a bit tricky because a merge commit has multiple parents. Unlike regular commits, where you simply go back to a previous state, reverting a merge requires specifying which branch's changes you want to keep.
Here's how you can do it:
1. Identify the Merge Commit:
- First, you need to identify the hash of the merge commit you want to revert. You can find this using the git log command:
git log --oneline --graph
- Look for the commit that has two parents, that's the merge commit.
2. Use git revert -m :
- This is the core command for reverting a merge. The -m option specifies which parent of the merge commit should be considered the "mainline" or the one that was merged in. You'll need to determine the correct parent number.
- Parent numbers start from 1, with 1 being the parent of the branch you were on when you performed the merge (usually your main branch), and 2 being the branch that was merged in. For example, if you merged a feature branch into main, parent 1 is the main, and parent 2 is the feature branch.
- Here's how you use it in practice:
- Let's say the hash of your merge commit is abcdefg, and you want to revert the changes brought in by the merged branch (parent 2), use:
git revert -m 1 abcdefg
- If you wanted to revert the changes in main and keep the merged changes, use:
git revert -m 2 abcdefg
3. Commit the Revert:
- After running the git revert command, Git will create a new commit that undoes the changes introduced by the merge. You might be prompted to write a commit message.
4. Push the Changes:
- Finally, push the revert commit to your remote repository:
git push origin main
5. Alternative Scenario:
- If you want to completely remove the merge commit (not recommended for shared branches), consider using git reset --hard . However, this rewrites history, and should be used cautiously. Use revert instead to have a safe history.
By following these steps, you can successfully revert a merge commit in Git. Remember to choose the correct parent number based on which branch's changes you want to discard.