git merge Tutorial

The short version

git merge integrates another branch into the current branch without requiring you to rewrite existing commits.

When it is a good fit

• merging a feature branch back into main
• preserving the real branch integration history
• integrating shared branches without rewriting history

Two common outcomes

Fast-forward

If the current branch has not diverged, Git can simply move the branch pointer forward.

Merge commit

If both branches moved forward independently, Git creates a merge commit that records where the histories joined.

Basic workflow

git checkout main
git fetch origin
git merge feature/login

Common flags and strategies

--ff-only

Only allow fast-forward merges. If the histories diverged, the merge fails instead of creating a merge commit.

git merge --ff-only origin/main

--no-ff

Create a merge commit even when a fast-forward would be possible. Teams sometimes use this to preserve the explicit branch boundary.

git merge --no-ff feature/login

Handling conflicts

git status
# resolve conflicts
git add <resolved-files>
git merge --continue

Abort if needed:

git merge --abort

When merge is a better choice than rebase

• the branch is already shared
• you want to preserve the integration graph
• your team values non-rewritten collaboration history

A practical decision rule

If your question is “Should I integrate this whole branch history here?”, merge is usually the more natural tool.

If your question is “Should I rewrite how my branch history is expressed?”, that usually points more toward rebase.