Both Git rebase and Git merge are commands in Git used to merge changes from different branches, but they handle the merge operation in different ways.
Git merge:
- The merge command is typically used to combine two different branches.
- When you execute
git merge, Git creates a new 'merge commit' with two parent commits: one is the last commit of the current branch (HEAD), and the other is the last commit of the branch being merged. - The presence of the merge commit preserves the integrity of the project history, clearly indicating the point in time when one branch was integrated into another.
- Merge is a non-destructive operation, meaning it does not alter the history of existing branches.
Git rebase:
- The rebase command is used to reapply changes from one branch onto another branch.
- When you execute
git rebase, Git reapplies the commits of the branch you're working on to the top of the target branch. - This operation rewrites history because it essentially recreates those commits as if you had performed the work again in the current state of the target branch.
- Rebase can produce a cleaner, linear history, so when viewing the project history, it appears as if changes occurred sequentially in chronological order.
Example: Suppose you're working on the feature branch and need to integrate the latest changes from the master branch into your feature branch. You can choose either merge or rebase to achieve this.
If you choose merge, Git creates a new merge commit that incorporates all changes from the master branch into the feature branch. This merge commit has two parent commits: one pointing to the last commit of the feature branch, and the other to the last commit of the master branch.
If you choose rebase, Git reapplies each commit from your feature branch onto the latest commit of the master branch. The result is that your feature branch appears to have started after the latest commit of the master branch, creating a clean, linear history without branches. However, note that if there are conflicts between changes on the feature branch and the master branch, you must manually resolve these conflicts during the rebase process.