Three-way merge
- Git course
- Beginner
- Lesson 59/80
- 4 min
Learn the three-way merge commit.
Three-Way Merge
When two branches share a common history but both contain separate commits, Git can perform a three-way merge. Git combines changes by comparing the common ancestor commit with the latest commits of both branches.
B -- C (main)
/
A ---
\
D -- E (feature)This operation generally creates a new merge commit that joins the two branches.
How Is a Merge Commit Created?
When a three-way merge completes, Git creates a merge commit that connects the histories of both branches. Unlike a regular commit, this commit has two parent commits.
B -- C ---- M (main)
/ /
A --- /
\ /
D -- E (feature)The M commit represents the merge result and preserves the history of both branches.
Practice Build a Merge Commit Command
While on the main branch, merge the feature branch by creating a separate merge commit instead of fast-forwarding. Assign the command to mergeCommand and print it.
Starter code
const mergeCommand = "";
// Birleştirme komutunu yazdırSample solution
const mergeCommand = "git merge --no-ff feature";
console.log(mergeCommand);Expected output
git merge --no-ff feature
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which three commits does Git consider in a three-way merge?
- The first commits of both branches and the latest commit
- The three oldest commits
- The common ancestor and the latest commits of both branches Correct answer
- Only the three latest commits of the current branch
Explanation: A three-way merge uses the common ancestor commit and the latest commit from each branch.
2 The Merge Commit Option
git switch main
git merge ____git switch main
git merge --no-ff featureExplanation: The --no-ff option makes Git create a separate merge commit even when a fast-forward would be possible.
3 Three-Way Merge Components
| Term | Meaning |
|---|---|
Ortak ata |
The shared branch history |
İki dalın sonu |
The compared tip commits |
Merge commit |
A commit with two parents |
Üç yönlü işlem |
Compares three commits |