C

Compare Branches Side by Side with Worktrees

Debug differences or run benchmarks by having multiple branches checked out simultaneously.

worktreedebuggingcomparisonbenchmarkingparallel development

When to use

You need to compare behavior, outputs, or performance between two branches. Having both checked out simultaneously lets you run them side by side without constant branch switching.

Pre-flight

  • Identify the two branches you want to compare (e.g., main vs feat/new-algorithm).
  • Ensure both branches are up to date with the remote.

Steps

  1. Keep your primary worktree on one branch (e.g., main).

    git checkout main
git pull origin main

  2. Create a worktree for the branch you want to compare against.

    git worktree add ../feature-comparison feat/new-algorithm

  3. Run your comparison tasks in separate terminals.

    # Terminal 1: Main branch
cd ~/project
npm run benchmark > main-results.txt

# Terminal 2: Feature branch
cd ~/feature-comparison
npm run benchmark > feature-results.txt

  4. Compare outputs using diff or your preferred comparison tool.

    diff main-results.txt ../feature-comparison/feature-results.txt

  5. Clean up when done.

    git worktree remove ../feature-comparison

Verification

  • Both branches run independently with their own outputs.
  • Comparison data helps identify behavioral differences or performance regressions.

Use case: Visual regression testing

Run both versions of a web app on different ports and compare visually:

# Main branch on port 3000
cd ~/project && PORT=3000 npm start

# Feature branch on port 3001
cd ~/feature-comparison && PORT=3001 npm start

Open both in your browser to compare UI changes side by side.

Follow-up

  • Document any significant differences found during comparison.
  • If benchmarking, run multiple iterations to account for variance.

Related scenarios