GitHub - How to revert changes to previous state

GitHub - How to Revert Changes to a Previous State

Learn how to effectively revert unwanted changes in your GitHub repository, whether it's a single commit or multiple commits, to maintain a clean and stable codebase.

Accidentally introducing bugs or unwanted features is a common scenario in software development. GitHub, built on Git, provides robust mechanisms to undo changes and restore your repository to a previous, stable state. This article will guide you through the different methods for reverting changes, ensuring you can confidently manage your commit history.

Understanding Git Revert vs. Git Reset

Before diving into the commands, it's crucial to understand the fundamental difference between git revert and git reset. Both commands undo changes, but they do so in distinct ways with different implications for your repository's history.

Git Revert vs. Git Reset: Preserving vs. Rewriting History

Reverting a Single Commit

The most common scenario is needing to undo the changes introduced by a specific commit. git revert creates a new commit that undoes the changes of the target commit, effectively adding an 'undo' commit to your history without deleting any existing commits.

# First, identify the commit you want to revert
git log --oneline

# Then, revert the commit using its hash
git revert <commit_hash>

Using git revert to undo a single commit

After running git revert, Git will open your default text editor to allow you to modify the commit message for the new revert commit. Save and close the editor to complete the revert. Finally, push the new revert commit to your remote repository.

git push origin <your_branch_name>

Pushing the new revert commit to GitHub

Reverting Multiple Commits

If you need to undo a series of commits, you can revert them individually or use a range. Reverting a range of commits will create a single new commit that undoes all changes from the specified range. When reverting a range, Git applies the reverts in reverse chronological order.

# Revert commits from <start_commit_hash> up to (but not including) <end_commit_hash>
git revert <start_commit_hash>..<end_commit_hash>

# To revert commits up to the HEAD (including the HEAD commit)
git revert <start_commit_hash>..HEAD

Reverting a range of commits

Similar to a single commit revert, Git will prompt you to provide a commit message for the new revert commit. After saving the message, push the changes to your remote repository.

Using git reset (with Caution)

While git revert is preferred for shared histories, git reset can be useful for local cleanup before pushing changes. It moves the branch pointer to an earlier commit, effectively discarding subsequent commits. There are three main modes for git reset:

• --soft: Moves the HEAD, but keeps the changes in the staging area.
• --mixed (default): Moves the HEAD, and unstages the changes.
• --hard: Moves the HEAD and discards all changes in the working directory and staging area.

1. Step 1

First, ensure you are on the correct branch and have no uncommitted changes you wish to keep.

2. Step 2

Identify the commit hash to which you want to reset. This is the commit you want to be the new HEAD of your branch.

3. Step 3

Execute git reset --hard <commit_hash> to move your branch to the specified commit and discard all subsequent changes. Be extremely careful with this command.

4. Step 4

If you need to push these changes to a remote repository (after a hard reset), you will likely need to use git push --force or git push --force-with-lease. Use this with extreme caution on shared branches.

# View your commit history to find the target commit
git log --oneline

# Reset to a specific commit, discarding all later changes
git reset --hard <target_commit_hash>

# If you must push this (use with extreme caution on shared branches)
git push --force origin <your_branch_name>

Example of git reset --hard for local history cleanup