Git Bisect Helper

Automate git bisect to find the commit that introduced a bug

Automate git bisect to find the commit that introduced a bug.

Instructions

1. Identify a "good" commit (where the bug didn't exist):

git log --oneline -20  # find a known good point

2. Start bisect:

git bisect start
git bisect bad                    # current commit is bad
git bisect good <good-commit>    # known good commit

3. At each step, test if the bug exists:

   • Run the failing test: npm test -- --grep "test name"
   • Or check manually
   • Then mark: git bisect good or git bisect bad

4. Automated bisect (if you have a test):

git bisect run npm test -- --grep "failing test name"
# Or with a custom script:
git bisect run bash -c 'npm run build && npm test'

5. When bisect finds the commit:

git show <bad-commit>    # review the culprit
git bisect reset         # return to original branch

Tips

• If a step can't be tested (e.g., won't compile): git bisect skip
• Bisect is O(log n) — 1000 commits takes ~10 steps