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Lesson 02.3: Branching

Duration: 45 minutes | Difficulty: Beginner

Learning Objectives​

By the end of this lesson, you will:

  • Understand what branches are and why they matter
  • Create, switch, and delete branches
  • Merge branches together
  • Resolve merge conflicts
  • Follow enterprise branching strategies

What is a Branch?​

A branch is an independent line of development:

main ─────●─────●─────●─────●─────●───── (production)
                \           /
feature ─────────●─────●───●───────────── (your work)

Think of it as: A parallel universe where you can experiment without affecting the main timeline.

Why Branching Matters​

Without Branches​

Developer A: Working on Feature X
Developer B: Working on Bug Fix Y
Both: Editing the same files on main
Result: Constant conflicts, broken builds

With Branches​

Developer A: feature/x branch (isolated)
Developer B: fix/y branch (isolated)
Both: Work independently
Result: Merge when ready, no conflicts during work

Branch Commands​

View Branches​

# List local branches
git branch

# List all branches (including remote)
git branch -a

# Show current branch
git branch --show-current

Create Branches​

# Create new branch
git branch feature/user-auth

# Create AND switch to new branch
git checkout -b feature/user-auth

# Modern alternative
git switch -c feature/user-auth

Switch Branches​

# Switch to existing branch
git checkout main

# Modern alternative
git switch main

Delete Branches​

# Delete local branch (safe - won't delete unmerged)
git branch -d feature/user-auth

# Force delete (even if unmerged)
git branch -D feature/user-auth

# Delete remote branch
git push origin --delete feature/user-auth

The Branch Workflow​

Step-by-Step​

# 1. Start from main (always up to date)
git checkout main
git pull

# 2. Create feature branch
git checkout -b feature/add-payment

# 3. Do your work
# ... edit files ...
git add .
git commit -m "Add payment form component"

# ... more work ...
git add .
git commit -m "Add payment validation"

# 4. Push branch to remote
git push -u origin feature/add-payment

# 5. Create Pull Request (on GitHub/GitLab)

# 6. After approval, merge to main
git checkout main
git pull
git merge feature/add-payment

# 7. Clean up
git branch -d feature/add-payment
git push origin --delete feature/add-payment

Merging Branches​

Fast-Forward Merge​

When main hasn't changed since you branched:

Before:
main ─────●─────●
                 \
feature ──────────●─────●

After (fast-forward):
main ─────●─────●─────●─────●
                      ↑
               feature merged
git checkout main
git merge feature/user-auth
# Fast-forward merge

Three-Way Merge​

When main HAS changed since you branched:

Before:
main ─────●─────●─────●─────● (new commits)
                \
feature ─────────●─────●

After (merge commit):
main ─────●─────●─────●─────●─────●
                \             /
feature ─────────●─────●─────┘
git checkout main
git merge feature/user-auth
# Creates merge commit

Handling Merge Conflicts​

Conflicts happen when both branches change the same lines.

Example Conflict​

$ git merge feature/update-header
Auto-merging src/Header.tsx
CONFLICT (content): Merge conflict in src/Header.tsx
Automatic merge failed; fix conflicts and then commit.

Conflict Markers​

<<<<<<< HEAD
<h1>Welcome to Our App</h1>
=======
<h1>Welcome to MyApp v2</h1>
>>>>>>> feature/update-header
  • <<<<<<< HEAD: Your current branch version
  • =======: Separator
  • >>>>>>> feature: Incoming branch version

Resolving Conflicts​

  1. Edit the file — choose or combine versions:
// Resolved:
<h1>Welcome to MyApp</h1>
  1. Stage the resolution:
git add src/Header.tsx
  1. Complete the merge:
git commit -m "Merge feature/update-header, resolve header conflict"

Pro Tip: Visual Merge Tools​

# Use VS Code for conflicts
git config --global merge.tool vscode
git config --global mergetool.vscode.cmd 'code --wait $MERGED'

# When conflict occurs
git mergetool

Branching Strategies​

GitHub Flow (Simple)​

Best for: Small teams, continuous deployment

main ────●────●────●────●────●────●────
          \    /    \    /    \    /
feature ───●──┘      │    \    │    \
                     │     │   │     │
fix ─────────────────●─────┘   │     │
                               │     │
feature ───────────────────────●─────┘

Rules:

  1. main is always deployable
  2. Create branch for any change
  3. Open PR for review
  4. Merge after approval
  5. Deploy from main

Git Flow (Enterprise)​

Best for: Larger teams, scheduled releases

main ────●────────────────●────────────● (releases)
          \              /            /
develop ───●────●────●──●────●────●──● (integration)
            \    /        \    /
feature ─────●──┘          \  /
                            \/
feature ────────────────────●

Branches:

  • main: Production releases only
  • develop: Integration branch
  • feature/*: New features
  • release/*: Release preparation
  • hotfix/*: Production fixes
main ────●────────────────●────────────●
          \              /            /
develop ───●────●────●──●────●────●──●
            \    /        \    /
increment/0001 ●           \  /
   (with spec.md,           \/
    plan.md,         increment/0002
    tasks.md)

Each increment branch includes:

  • Feature code
  • spec.md (requirements)
  • plan.md (architecture)
  • tasks.md (implementation plan)

Practice Exercise​

# 1. Create a test repository
mkdir branch-practice
cd branch-practice
git init
echo "# Branch Practice" > README.md
git add .
git commit -m "Initial commit"

# 2. Create a feature branch
git checkout -b feature/add-description

# 3. Make changes
echo "## Description" >> README.md
echo "This is a practice repository." >> README.md
git add .
git commit -m "Add description section"

# 4. Switch back to main
git checkout main

# 5. Make a different change on main
echo "## License" >> README.md
echo "MIT" >> README.md
git add .
git commit -m "Add license section"

# 6. Merge feature branch
git merge feature/add-description

# 7. View the result
cat README.md
git log --oneline --graph

# 8. Clean up
git branch -d feature/add-description

Branch Naming Conventions​

Common Patterns​

# Features
feature/user-authentication
feature/payment-processing
feature/0001-user-auth          # With SpecWeave increment ID

# Bug fixes
fix/login-crash
bugfix/payment-calculation
hotfix/security-vulnerability

# Other
release/v1.2.0
docs/update-readme
refactor/user-service
test/add-auth-tests

Enterprise Standards​

Many companies require:

  • Ticket reference: feature/JIRA-123-user-auth
  • Increment reference: feature/0001-user-auth
  • Team prefix: team-a/feature/user-auth

Key Takeaways​

  1. Branches enable parallel work — isolate changes until ready
  2. Create branch for every change — never work directly on main
  3. Keep branches short-lived — merge frequently to avoid conflicts
  4. Merge conflicts are normal — resolve them calmly
  5. Follow your team's strategy — consistency matters

Next Lesson​

Now let's learn how to collaborate with others using Git.

→ Continue to Lesson 02.4: Collaboration