Head of DevRel
By the end of this tutorial, you will have a practical understanding of how to use
git rebase to integrate changes from one branch to another and how to maintain a clean commit history.
Want a more information about this image? Checkout the "Understanding Git Rebase" guide.
Basic understanding of Git
Git installed on your system
Git rebase is a powerful command that allows you to integrate changes from one branch into another. Instead of merging, which takes all the changes in one branch and merges them into another with a new
rebase takes a different approach. It replays your changes on top of the branch you're rebasing onto. This results in a cleaner, more linear commit history.
Of course, it's not all sunshine and rainbows - problems do pop up. So, lets take a look at how to use
git rebase and also how to deal with conflicts when they arise.
Lets go ahead and create a test repository that we can use to play around with
# Initialize a new repository git init rebase-demo cd rebase-demo # Create a main branch for primary development git checkout -b main # Create a file and commit it to the main branch echo "Initial content" > file.txt git add file.txt git commit -m "Initial commit on main"
Now, lets create a new feature branch that we will
rebase into the main branch later. We will create a simple file and commit that change to the branch.
# Create a feature branch and add a file to it. git checkout -b feature-branch echo "Some feature content" >> file.txt git commit -am "Add feature content"
Lets go back to the main branch and make some more changes. These changes are what our
rebase will be added to.
# Go back to the main branch and make changes git checkout main echo "Another line in main" >> file.txt git commit -am "Update in main"
Now, you have two branches:
feature-branch, both with unique commits.
Now, the magic happens. We switch to the feature branch, and
rebase it into main.
git checkout feature-branch git rebase master
Wait, is that it? Is it really that simple?
It can be, for sure! Assuming all went well, the commit history will show the
feature-branch commits will be on the
main branch. Those experienced or very observant developers may have noticed a problem above... we will have a conflict. However, not all is lost. Lets take a look at how you can adapt to this situation and fix any minor problems
During the rebase, you'll encounter a conflict because line 2 of
file.txt is different in each branch. That's ok - no need to panic. All merge conflicts can be fixed with the same basic steps. Here's how to resolve it:
Identifying the Conflict: Git will indicate that there's a conflict. You'll see a message similar to:
Auto-merging file.txt CONFLICT (content): Merge conflict in file.txt error: could not apply a669cc6... Add feature content
This message tells you that there's a conflict in
file.txt that needs resolution.
Evaluating the status: One of the great things about Git is that you can always ask for a status update to see what is going on and what you may need to work on. Just make note of the problems to fix and handle them one at a time.
interactive rebase in progress; onto 117fde3 Last command done (1 command done): pick a669cc6 Add feature content No commands remaining. You are currently rebasing branch 'feature-branch' on '117fde3'. (fix conflicts and then run "git rebase --continue") (use "git rebase --skip" to skip this patch) (use "git rebase --abort" to check out the original branch) Unmerged paths: (use "git restore --staged <file>..." to unstage) (use "git add <file>..." to mark resolution) both modified: file.txt
Viewing the Conflict: Depending on how many changes you are dealing with, you may know exactly what the problem is. Alternatively, you can also us
git diff to see the changes. Open
file.txt in your favorite editor. You'll see the conflicting changes demarcated like this:
Initial content <<<<<<< HEAD Another line in master Some feature content >>>>>>> Add feature content
The content between
<<<<<<< HEAD and
======= is from the
main branch, and the content between
>>>>>>> Add feature content is from the
Resolving the Conflict: Edit
file.txt to keep the content you want. For instance, if you want to keep the content from both branches but want the feature content to appear before the master content, you'd modify
file.txt to look like this:
Initial content Some feature content Another line in master
Save and close the file.
Marking the Conflict as Resolved: After resolving the conflict, mark it as resolved with Git:
git add file.txt
Continuing the Rebase: Once the conflict is resolved and marked as such, continue the
git rebase --continue
If there are more conflicts, Git will pause again and let you resolve them. If there are no more conflicts, the
rebase will complete.
git log to see a clean, linear history of commits, showing that the feature branch commits now come after the master branch commits. Once the
rebase is successful, it will be a fast-forward merge, maintaining a linear history.
Git rebase is a powerful tool for maintaining a clean commit history and integrating changes from one branch into another. While it can be a bit more complex than merging, especially when conflicts arise, the resulting linear history can be worth the extra effort, especially in large projects.
Remember, practice makes perfect. Feel free to experiment with git in safe environments (like our demo repo) before applying it to larger projects. Happy rebasing!