Understanding the Difference Between Git Reset and Git Revert

In the world of software development, managing changes effectively is crucial. Git, as a version control system, offers powerful tools to help developers maintain a clean and manageable code history. Among these tools, git reset and git revert are often sources of confusion. This blog post aims to demystify these commands, explaining their differences and appropriate use cases, complete with ASCII illustrations for clarity.

What is Git Reset?

git reset is a command used to undo changes. It allows you to reset your current HEAD to a different state. It’s a way to go back in time and make it as if some changes or commits never happened.

How it Works

Imagine your Git commit history as a timeline (each letter represents a Git commit):

A - B - C - D - E (HEAD)

Here, A to E are different commits, with E being the latest. If you want to go back to commit C, discarding changes in D and E, you would use:

git reset --hard C

After the reset, your timeline looks like this:

A - B - C (HEAD)

Types of Resets

  • --mixed (default): Resets the staging area to match the HEAD. Working directory
  • --soft: Keeps your working directory and staging area as they were. Only the HEAD is moved.
  • --hard: Resets both the staging area and working directory. This discards all changes.

Use Cases

  • Undo local commits that haven’t been pushed.
  • Clean up local history before merging branches.

What is Git Revert?

git revert, on the other hand, is used to create a new commit that reverses the changes made by a previous commit. It’s a safe way to undo changes that have already been shared with others.

How it Works

Continuing with our timeline:

A - B - C (HEAD)

If you realize that commit B introduced an issue, but it has already been pushed or shared, you can use git revert:

git revert B

This creates a new commit F that undoes the changes made in B:

A - B - C - F (HEAD)

Use Cases

  • Undo changes from a commit that’s already been pushed to a remote repository.
  • Maintain a consistent history for all collaborators.

Key Differences: Reset vs Revert

History Alteration

  • Reset: Alters history by moving the branch pointer.
  • Revert: Keeps history and adds a new commit.

Shared History

  • Reset: Best for local changes.
  • Revert: Safe for shared changes.

Direction

  • Reset: Like rewinding a tape.
  • Revert: Adds a new “undo” commit, moving forward.

Conclusion

Understanding git reset and git revert is essential for maintaining a clean and understandable project history. Use git reset for local changes and git revert for changes that have been shared.

Remember: Manipulating history can be powerful, but with great power comes great responsibility. Always ensure you understand the implications of these commands before using them, especially in a collaborative environment.