What is the difference between merge --squash and rebase?

In Git, both git merge --squash and git rebase are tools for merging code, but they have distinct approaches and use cases. Below, I will explain the differences between the two in detail:

1. Operation Method

• git merge --squash: When you run git merge --squash feature-branch, Git consolidates all changes from the feature-branch into a single commit and applies it to the current branch. This means that regardless of how many commits exist on feature-branch, only one new commit is created after merging. This operation does not preserve the history of the original commits.

• git rebase: The git rebase command re-applies commits from one branch onto another. For example, executing git rebase master on feature-branch takes each commit from feature-branch and reapplies them sequentially after the current tip of the master branch. This creates a more linear history.

2. Use Cases

• git merge --squash is typically used when merging a feature branch back into the main branch (e.g., master or main) without preserving the full commit history of the feature branch. This helps maintain a clean and tidy history for the main branch.

• git rebase is suitable when updating a branch (usually a feature branch) to include the latest changes from the base branch (e.g., master or main). By rebasing, you ensure the feature branch incorporates all recent commits from the base branch before merging back into the main branch, which helps avoid merge conflicts.

3. Examples

Suppose you develop a new feature on feature-branch, resulting in multiple commits:

• Using git merge --squash:

  bash
  git checkout master
  git merge --squash feature-branch
  git commit -m "Add new feature in a single commit"

  This ensures that only one commit is merged into master, regardless of the number of commits on feature-branch.

• Using git rebase:

  bash
  git checkout feature-branch
  git rebase master

  This re-bases each commit on feature-branch onto the latest tip of master. If new commits exist on master, the commits on feature-branch are reapplied after these updates.

4. Conclusion

In summary, if you prioritize a clean history and don't care about individual commits from the merged branch, choose git merge --squash. If you prefer a detailed development history and a linear commit history, git rebase is preferable. In team collaboration, the choice should align with the team's specific needs and workflow.