Three-Way Merge

If both branches have moved on independently, Git cannot just fast-forward. Instead it performs a three-way merge: it looks at the common ancestor and the two branch tips, and produces a new commit that combines them.

This new commit is the merge commit. It has two parents, one from each branch:

git switch main
git merge feature -m "Merge feature"

The -m flag provides the merge commit message directly, so Git does not open an editor.

Most of the time Git can combine the changes from both branches automatically, as long as they touch different parts of the files. Conflicts only happen when both branches changed the same lines, which is the topic of the next lesson.