git merge vs rebease

Merge and rebase both combine Git histories, but they do it differently.

Merge

git switch main
git merge feature

Git creates a merge commit that joins the two branches:

A---B---C main
     \   \
      D---E---M

Advantages

• Preserves the true branch history.
• Safe for shared branches.
• Does not rewrite existing commits.

Trade-off

• Can produce many merge commits and a noisier history.

Rebase

git switch feature
git rebase main

Git moves the feature commits so they appear to have been created from the latest main:

A---B---C main
         \
          D'---E' feature

Advantages

• Produces a clean, linear history.
• Makes logs and git bisect easier to follow.

Trade-off

• Rewrites commit history: D and E become new commits D' and E'.
• Can require resolving conflicts commit by commit.

Practical rule

Use rebase to update your own local feature branch:

git switch feature
git fetch origin
git rebase origin/main

Use merge when combining shared or already-published history:

git switch main
git merge feature

Avoid rebasing commits that other people may already be using. A common workflow is: rebase locally, then merge or fast-forward into main.