Undoing an Accidental `git commit –amend`

Introduction

In Git, amending a commit is a common task used to modify the most recent commit. However, there are scenarios where you may accidentally amend instead of creating a new commit and want to revert that change without affecting your project history. This tutorial covers how to undo an accidental git commit --amend while preserving your changes.

Understanding Git Commits

Before diving into solutions, let’s recap some fundamental Git concepts:

• Commit: A snapshot of your codebase at a particular point in time.
• HEAD: Refers to the latest commit on your current branch.
• Reflog: A log that records updates to references in your repository, providing an audit trail of changes.

Undoing git commit --amend

Scenario

You’ve amended the last commit instead of committing new changes separately. You need to undo this amendment and create a separate commit for those changes while keeping the original commit intact.

Solution 1: Using Reflog with Soft Reset

The reflog is invaluable for tracking changes in your repository, even after operations that alter history locally.

1. Identify Previous Commit Hash

   • Use the command:

     git reflog
     

   • Locate the commit hash before the amend operation. It should be labeled as HEAD@{1} or similar, depending on recent actions.

2. Soft Reset to the Original Commit

   • Execute a soft reset using the identified commit hash from the reflog:

     git reset --soft <previous_commit_hash>
     

   • This command moves your HEAD pointer back and stages all changes that were part of the amend.

3. Create a New Commit

   • Now, create a new commit with those staged changes:

     git commit -m "New changes separate from previous commit"
     

Solution 2: Using Branches for Safety

If you prefer to work in isolation before making changes, creating a temporary branch is a safe approach.

1. Create and Switch to a New Branch

   • Create a new branch pointing to the state before the amend:

     git checkout -b fixing-things HEAD@{1}
     

2. Perform a Soft Reset

   • Perform a soft reset on this branch:

     git reset --soft HEAD^
     

   • This step ensures that all changes are staged for commit.

3. Commit Changes Separately

   • Commit the staged changes to create a new, separate commit:

     git commit -m "Newly separated commit"
     

4. Merge or Rebase as Needed

   • If needed, merge this branch back into your main working branch.

Solution 3: Cherry-Picking Changes

If you have other changes to apply after undoing the amend, cherry-pick can be a useful method.

1. Reset HEAD Softly

   • Identify and reset using reflog or any prior known commit:

     git reset --soft <previous_commit_hash>
     

2. Cherry-Pick Changes

   • If there are other changes you need to apply, use cherry-pick on those commits:

     git cherry-pick <commit_hash_to_cherrypick>
     

Best Practices

• Commit Early and Often: Regularly commit changes to avoid large, complex amendments.
• Use Stashes Wisely: If you have uncommitted work, stash it before resetting branches or commits.
• Test Before Pushing: Always test your repository state after making changes locally, especially if working with a shared remote.

Conclusion

Undoing an accidental git commit --amend is straightforward using Git’s powerful tools like reflog and reset. By understanding how to manipulate the HEAD pointer and utilize branches for safety, you can effectively manage your project history without losing any work. Follow these steps to maintain a clean, organized repository and ensure your changes are committed as intended.