Merging Branches

What is Merging?

Merging combines the changes from one branch into another. It's how you bring your completed feature back into the main code.

The Merge Workflow

# 1. Switch to the branch you want to merge INTO
git switch main
2. Merge the feature branch
git merge feature-login

Before Merge

main:     A ─── B ─── C
                       \
feature:                D ─── E

After Merge

main:     A ─── B ─── C ─────── F (merge commit)
                       \       /
feature:                D ─── E

Git creates a merge commit (F) that combines both histories.

Fast-Forward Merge

If main hasn't changed since you branched, Git does a simpler fast-forward merge:

Before:
main:     A ─── B
                 \
feature:          C ─── D
After (fast-forward):
main:     A ─── B ─── C ─── D

No merge commit needed — Git just moves the pointer forward.

Merge Conflicts

Sometimes Git can't automatically merge because both branches changed the same lines. This is called a merge conflict.

<<<<<<< HEAD
This is the line from main
=======
This is the line from feature
>>>>>>> feature-login

To resolve:

• Open the file with the conflict
• Choose which version to keep (or combine them)
• Remove the conflict markers (<<<<<<<, =======, >>>>>>>)
• Stage and commit: git add . && git commit -m "Resolve merge conflict"

Summary

💡 Tip: Always switch to main first, then merge the feature branch into it.