What is git rebase?
Rebasing in Git means transferring the base of one branch onto another. When you rebase the feature branch with the main branch, you're moving the entire feature branch to begin on the tip of the main branch, incorporating all the new commits in the main. This can help resolve conflicts early and makes the history of your project linear and easier to follow.
Prerequisites
Before rebasing, ensure you have a clean working directory. This means that you don't have any files either untracked by Git (meaning that they exist locally but aren't tracked by Git), or have any uncommitted changes to existing files (meaning that you have changes to files locally but they haven't been added to the staging area, or pushed to the remote repository yet). Check this by running git status
. If there are uncommitted changes, either commit them or stash them using git stash
.
This command will temporarily stash these files for later use. Once you've rebased successfully and are satisfied with the changes, you can restore these stashed files back to the working directory by running git stash pop
.
Step-by-step guide to rebase a feature branch with main
Now that we have a clean working directory, let's start the rebase.
Step 1: Update Your Local Main Branch
Purpose The goal here is to ensure that your local main
branch is synchronized with the remote main
branch. This is important because it ensures that any changes you're integrating into your feature branch are based on the latest version of your project, avoiding conflicts and simplifying the integration of new features.
Commands
git checkout maingit pull origin main
git checkout main
- What it does: This command switches your current working directory to the
main
branch. It updates your project files to reflect the state of themain
branch, setting the stage for you to sync it with the remote repository. - Under the hood: The
checkout
command adjusts theHEAD
pointer to point to themain
branch and updates the working directory to match the snapshot of the project at the latest commit on that branch.
git pull origin main
- What it does: This command fetches the latest changes from the
main
branch of the remote repository (typically calledorigin
) and merges them into your localmain
branch. - Under the hood:
git pull
is a compound command that first executesgit fetch
with the given branch (fetching updated data from your remote repository), followed bygit merge
, which integrates the remotemain
branch into your localmain
branch.
Step 2: Switch to Your Feature Branch
Purpose Switching to your feature branch prepares you to rebase it onto the updated main
branch. This is where you're developing new features or changes, isolated from the main
branch until they're ready.
Commands
git checkout feature-branch
git checkout feature-branch
- What It Does: Moves you from the
main
branch (or any other branch you might be on) to your feature branch. - Under the Hood: Similar to the checkout to
main
, this changes your working directory and updates the files to reflect the state offeature-branch
at its latest commit. It also adjusts theHEAD
pointer to reference thefeature-branch
.
Step 3: Perform the Rebase
Purpose Rebasing is a powerful tool for maintaining a clean project history. It allows you to take all the changes that were committed on one branch and replay them on another branch.
Commands
git rebase main
git rebase main
- What it does: This repositions the
feature-branch
to begin at the tip of themain
branch. Essentially, it moves the starting point offeature-branch
to the end ofmain
, then applies each change made on thefeature-branch
one by one. - Under the hood:
git rebase
changes the base of your feature branch from its current base to whatevermain
is now. This operation can be complex if there are conflicting changes betweenmain
andfeature-branch
. Git will pause the rebase and ask you to resolve any conflicts manually. Once all conflicts are resolved and all changes are applied, the feature branch will appear as if it was created based on the current end of themain
branch.
Step 4: Resolve conflicts (if any):
During rebase, you may encounter conflicts. Git will stop at the first commit that causes conflict and give you the chance to resolve it. You can identify the files with conflicts using git status
.
Open the conflicted files and make the necessary changes.
After resolving conflicts in a file, add it to the index using:
Terminalgit add <filename>Once all conflicts are resolved, continue the rebase process with:
Terminalgit rebase --continue
Repeat this process until all conflicts are resolved and the rebase is complete.
If needed, abort the rebase: If you find that the rebase is too complex or not going as planned, you can abort and return your branch to the state it was in before rebasing started:
Terminalgit rebase --abortPush the changes: After the rebase is completed successfully, you'll need to push your changes to the remote feature branch. Since rebase changes the branch's history, you might need to use force push:
Terminalgit push origin feature-branch --forceCaution: Be careful with force pushing, as it can overwrite changes in the remote branch. Ensure that no one else is working on the feature branch or that all team members are aware of the rebase.
Benefits of rebasing
- Simplified history: Rebasing creates a linear project history, which makes it easier to understand changes without the complexities of merge commits.
- Early conflict detection: By regularly rebasing the main branch into your feature branch, conflicts are detected and resolved sooner rather than later.
For further reading on git rebase
see the official Git documentation.