Module 4 – Rebase Regularly and Interactively
The Git Rebase feature provides developers with a powerful tool to maintain a clean and understandable commit history. By understanding and utilizing rebase, you can streamline your development process, simplify troubleshooting, and make collaboration more effective.
In this module, we’ll dig deeper into the concept of rebasing, its significance, and its practical applications. You’ll learn how to integrate changes from one branch to another, modify existing commit history, and interactively alter your commits. Additionally, we’ll compare and contrast rebasing with merging, another common Git operation, to help you discern when to use each.
We will cover:
- 4.1 What is Rebasing?
- 4.2 Basic Rebasing
- 4.3 Interactive Rebasing
- 4.4 Rebasing vs Merging
- 4.5 Dealing with Rebase Conflicts
By the end of this module, you’ll be comfortable using the
git rebase command in various scenarios and be equipped with the knowledge to handle any potential conflicts that may arise during the rebasing process. Let’s dive in and explore the powerful feature of rebasing in Git.
What is Rebasing?
Rebasing is one of two Git processes for integrating changes from one branch into another (the other is merging). It takes the changes made in one branch and “replays” them on another branch.
Rebasing can be used in several ways:
- To keep your feature branch up-to-date with the latest code from the main branch.
- To make your feature branch’s history cleaner by making it appear as if your changes were made off the most recent commit on the main branch.
In its simplest form, rebasing can be done using the
git rebase [branch] command. This command moves the changes made in the current branch onto the branch specified.
Interactive rebasing, invoked with
git rebase -i [base], provides a more flexible and powerful way of altering commits. This can be useful for:
- Squashing Commits: Combining multiple commits into one.
- Editing Commits: Modifying specific commits.
- Reordering Commits: Changing the order in which commits were made.
- Dropping Commits: Removing specific commits from the branch.
Rebasing vs Merging
While both rebasing and merging allow you to integrate changes from one branch into another, they do it in different ways and the resulting history will look different.
Rebasing creates a linear history, which can be beneficial for understanding the high-level feature changes without the noise of the low-level commits. However, it changes the existing commit history.
Merging, on the other hand, preserves the original history and the context of the branch, but the history can become complex to understand.
Dealing with Rebase Conflicts
Just like with merging, rebasing can also result in conflicts. When a rebase conflict occurs, Git will pause the rebase at the conflicting commit, allowing you to resolve the conflict before continuing.
Exercises and Practice
Exercise 1: Create a new branch and make some commits. Switch back to the ‘main’ branch, make a new commit, then rebase the new branch onto ‘main’.
Exercise 2: Practice interactive rebasing: create a new branch, make several commits, then use
git rebase -i to squash the commits together.
Exercise 3: Create a situation where a rebase conflict will occur. Try to rebase these branches and resolve the resulting conflict.
Exercise 4: Perform both a rebase and a merge on the same two branches, and observe the difference in the Git log.
Exercise 5: Create two branches, ‘branch1’ and ‘branch2’, from ‘main’. Add some unique commits to each one. Rebase ‘branch1’ onto ‘branch2’ and observe the result. Try to understand what happened and why.
Exercise 6: Practice rebasing with the
--onto option. Create three branches ‘branch1’, ‘branch2’, and ‘branch3’. Make some unique commits on each one. Then rebase ‘branch1’ onto ‘branch3’, leaving out the changes in ‘branch2’ (
git rebase --onto branch3 branch2 branch1).
Exercise 7: Create a new branch and make several commits. Then, perform an interactive rebase and use the “reword” command to change the commit messages.
Exercise 8: Use interactive rebase to edit a commit. Make a commit with a deliberate mistake, then use interactive rebase to fix the mistake.
Exercise 9: Practice resolving rebase conflicts. Create a branch, make some changes, and commit them. Switch back to ‘main’, make conflicting changes, and commit them. Try to rebase the branch onto ‘main’, resolve the conflicts, and complete the rebase.
Exercise 10: Explore the
git pull --rebase command. Make a commit on a branch in your local repository. Then, on a different clone of the repository (or on a web-based interface like GitHub), make a commit on the same branch. On the local repository, try to pull the new commit. Do this once with a regular
git pull and once with
git pull --rebase, and observe the difference.
Each of these exercises will provide hands-on experience with different aspects of rebasing. This will not only help you understand when and why to use rebase, but also how to use it effectively in different situations.
Branching, Merging and Options