Git Rebase vs. Merge: A Complete Guide

In this blog post, I will show you the difference between git merge and git rebase with an example.

Let’s consider a scenario where developers are working on different branches for feature development and bug fixes, and they need to integrate their changes into the Develop branch.

Git Rebase

1. Rebase from Feature to Develop:

git checkout Feature
git rebase Develop

This will take the commits from the Feature branch and apply them on top of the Develop branch. The result will be a linear history, where the changes from the Feature branch come after the changes from the Develop branch.

For example:

Develop:  A --- B --- C
            \
Feature:      D --- E

After the rebase:

Develop:  A --- B --- C --- D' --- E'

1. Note: The commits D and E are copied and applied as D’ and E’ to the Develop branch.

2. Rebase from BugFix to Develop:

git checkout BugFix
git rebase Develop

Similar to the previous rebase, this will take the commits from the BugFix branch and apply them on top of the Develop branch. The history will be linear, with the changes from the BugFix branch coming after the changes from the Develop branch.

For example:

Develop:  A --- B --- C --- D' --- E'
               \
BugFix:          F --- G

After the rebase:

Develop:  A --- B --- C --- D' --- E' --- F' --- G'

1. Note: The commits F and G are copied and applied as F’ and G’ to the Develop branch.

Git Merge

Now, let’s use Git Merge to integrate the changes from the feature branch and the bug fix branch into the Develop branch.

3. Merge Feature into Develop:

git checkout Develop
git merge Feature

This will create a new merge commit that combines the changes from the Feature branch and the Develop branch.

For example:

Develop:  A --- B --- C --- D' --- E' --- F' --- G' --- Merge1
               \                           /
Feature:          D --- E ---------------

Merge BugFix into Develop:

git checkout Develop
git merge BugFix

This will create another merge commit that incorporates the changes from the BugFix branch into the Develop branch.

For example:

Develop:  A --- B --- C --- D' --- E' --- F' --- G' --- Merge1 --- Merge2
               \                           /                    /
BugFix:          F --- G --------------------------------------

Conclusion

In this example, we demonstrated how Git Rebase and Git Merge work with multiple branches. Git Rebase allows you to create a linear history by applying changes from one branch onto another. On the other hand, Git Merge is used to combine changes from multiple branches, creating a new merge commit.

Both approaches have their merits, and the choice depends on the specific workflow and the desired commit history. Understanding when to use Git Rebase or Git Merge will help ensure a clean and organized version control history for your projects.