Git Reset vs Revert: When to Use Each Command?

Introduction

In the world of version control systems, mistakes are bound to happen. Whether you accidentally reset your branch to the wrong commit or removed vital changes, Git provides a robust mechanism to recover from such scenarios. This guide delves into the intricacies of Git reset vs. revert operations, empowering you to undo unintended changes and restore your repository to its desired state.

Overview

• Understand the key differences between Git reset and revert operations and their appropriate use cases.
• Learn the different modes of Git reset (soft, mixed, hard) and their effects on the branch pointer, staging area, and working directory.
• Master the techniques for reversing Git reset operations, including soft, mixed, and hard resets.
• Gain practical knowledge of common errors and troubleshooting methods when reversing a Git reset.
• Recognize the importance of preventive measures such as frequent commits, backups, and using Git stash to safeguard against accidental resets or other mistakes.

What is Git Reset?

Before we dive into reversing a reset, it’s essential to understand the underlying concept of the `git reset` command. This command is primarily used to undo local changes and move the branch pointer (HEAD) to a different commit. Depending on the options used, `git reset` can discard committed changes, unstaged changes, or both.

Git reset [<mode>][<commit>]]

In addition to perhaps updating the index (resetting it to the tree of <commit> ) and the working tree, depending on <mode>, this form resets the current branch head to <commit>. ORIG_HEAD is set to the current branch tip prior to the operation. —mixed is the default if [<mode>] is not specified. The following must be the case for the : Soft, reset or Mixed

Modes of Opernation in Git Reset

There are different modes of operation for `git reset`, but soft mixed and hard are the three main modes: 

1. Soft Reset: Moves the branch pointer to the specified commit, but keeps the changes in the staging area and the working directory. It does not touch the index file  and working tree at all , but resets the head to <commit>.
2. Mixed Reset (default): Moves the branch pointer and resets the staging area to match the specified commit, but leaves the working directory unchanged and therefore resetting the index and not the working tree.
3. Hard Reset: Moves the branch pointer, resets the staging area, and overwrites the working directory with the specified commit. It resets the index and working tree.

Also Read: A Comprehensive Guide to Common Git Commands in Data Science

Reversing a Git Reset

Reversing a Git reset involves undoing the effects of the `git reset` command. The process varies depending on the mode used and the desired outcome. Here are the common scenarios and their respective solutions:

Reversing a Soft Reset

A soft reset is relatively straightforward to reverse since it preserves the changes in the staging area and working directory. To undo a soft reset, you can use the `git reset` command with the `–soft` option, followed by the commit hash you want to restore:

#bash
$ git reset --soft <commit-hash>
#This command will move the branch pointer back to the specified commit, effectively reverting the soft reset.

This command will move the branch pointer back to the specified commit, effectively reverting the soft reset.

Example :  git soft 

Undo a commit and redo

$ git commit ...
$ git reset --soft HEAD^      (1)
$ edit                        (2)
$ git commit -a -c ORIG_HEAD  (3)

If you do not need to edit the message further, you can give -C option instead.

Reversing a Mixed Reset

In a mixed reset, the staging area is reset, but the changes remain in the working directory. To reverse this reset, you can first unstage the changes using `git reset HEAD`, and then create a new commit with the unstaged changes:

```bash
$ git reset HEAD
$ git add .
$ git commit -m "Reverting mixed reset"

This process effectively reverses the mixed reset by creating a new commit with the previously unstaged changes.

Reversing a Hard Reset

Example : 

Undo a commit, making it a subject branch

$ git branch subject/wip          (a)
$ git reset --hard HEAD~3       (b)
$ git switch subject/wip          (c)

• You realise that some of the commits you made were premature to be in the master branch. Make a topic/wip branch out of the current HEAD so you can continue refining them there.
• To remove those three commits, rewind the master branch.
• Continue working by switching to the subject/wip branch.

A hard reset is the most destructive form of reset, as it overwrites the working directory with the specified commit. Reversing a hard reset requires recreating the lost changes from a backup or reverting to an older commit if available.

If you have a backup or a stash of your changes, you can apply them to the current branch:

#bash
$ git stash apply
 

Alternatively, if you have an older commit that contains the desired changes, you can revert to that commit using `git reset` or `git revert`:

# Using git reset (destructive)
$ git reset <older-commit-hash>

# Using git revert (non-destructive)
$ git revert <commit-hash-to-revert>

Git Revert: Revert Some Existing Commits

The `git revert` command creates a new commit that undoes the changes introduced by the specified commit, effectively reversing its effects.

Example :

$git revert HEAD~3

Revert the changes specified by the fourth last commit in HEAD and create a new commit with the reverted changes.

Note: To undo the effects of some previous commits (usually just a bad one), use git revert to record some new changes. You should see git-reset[1], especially the –hard option, if you want to erase all uncommitted changes in your working directory. You should be able to access git-restore[1], specifically the –source option, if you wish to extract individual files as they were in a previous commit. Use caution when utilising these options as they will both remove any uncommitted modifications from your working directory.

Common Errors and Troubleshooting

While reversing a Git reset, you might encounter some common errors and issues. Here are a few scenarios and their respective solutions:

• Error “Cannot revert”: When you see an error message such as “Cannot revert as the given commit has already been reverted,” it indicates that the commit you are attempting to undo has already been undone on the current branch. To carry out the revert action in this situation, you can either checkout an alternative branch or establish a new branch.
• Resolving Merge Conflicts: Reversing a Git reset could occasionally result in merge conflicts. This happens when there is a conflict between the changes that you are trying to rollback and other commits in the repository. You must manually edit the files that are at odds, take out the conflict markers, and stage the resolved changes before committing in order to resolve merge conflicts.
• Recovering Lost Commits: If you’ve accidentally lost commits due to a hard reset or force-pushed a branch, you can attempt to recover the lost commits using the `git reflog` command. This command displays a log of all the commit references in the repository, including those that are no longer part of any branch.

$ git reflog

Locate the commit hash of the lost commit, and then create a new branch pointing to that commit:

$ git branch <new-branch-name> <commit-hash>

This will create a new branch with the recovered commit, allowing you to continue working or merge the changes back into your main branch.

Conclusion

Git reset is a powerful tool for undoing changes and managing the state of your repository. However, reversing a Git reset can be a complex task, especially when dealing with hard resets or lost commits. By understanding the different modes of Git reset vs. revert operations and their corresponding reversal techniques, you can confidently undo unintended changes and restore your repository to its desired state.

Remember, prevention is always better than cure. It’s advisable to commit your changes frequently, create backups, and use Git’s stash feature to ensure you can easily recover from accidental resets or other mistakes.

Frequently Asked Questions

Shikha Sen

With 4 years of experience in model development and deployment, I excel in optimizing machine learning operations. I specialize in containerization with Docker and Kubernetes, enhancing inference through techniques like quantization and pruning. I am proficient in scalable model deployment, leveraging monitoring tools such as Prometheus, Grafana, and the ELK stack for performance tracking and anomaly detection.

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