What is the difference between git merge and git rebase, and when do you use each?
CI/CD & GitOps · Intermediate level
Answer
git merge combines histories and preserves the branch relationship. git rebase rewrites local commit history by replaying commits on a new base. I use merge for shared branch integration and rebase for cleaning my own local branch before opening or updating a PR.
Technical explanation
Use commands that preserve team auditability on shared branches; rewrite only local or explicitly coordinated history.
Always run the relevant test suite after conflict resolution or cherry-picking because code may compile but behavior can change.
Git history is both collaboration state and audit evidence, so choose merge, rebase, revert, and reset based on whether history is shared.
Short-lived branches reduce merge conflicts and make CI feedback meaningful; long-lived branches increase drift and integration risk.
Tags, release branches, signed commits, and changelogs connect source history to released artifacts and operational traceability.
Prefer safe, reviewable operations on shared branches: revert bad changes, open PRs for backports, and avoid force-pushes unless the team explicitly coordinates them.
Hands-on example
1. Practice the Git operation for: What is the difference between git merge and git rebase, and when do you use each in a throwaway repository with main, feature, release, and hotfix branches.
2. Create commits on multiple branches, then run the relevant commands: git merge, git rebase main, git cherry-pick <sha>, git revert <sha>, git tag -a v1.2.3, or git reset --hard only on a private branch.
3. Inspect the result with git log --oneline --graph --decorate --all and verify whether history was preserved, replayed, tagged, or safely undone.
4. Push through a pull request with required CI checks, run tests after conflict resolution or cherry-pick, and document why that operation was chosen.
5. For release scenarios, build from a signed tag, publish the artifact with the commit SHA and version, and confirm the release notes match the merged changes.
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