/scout

Scout Git Bisect Reference

Purpose: Commit-level regression isolation workflow and guardrails. Read when: The issue looks like a regression and git bisect is faster than wider code archaeology.

Contents

• Basic workflow
• Finding the good commit
• Automation
• Skip and recovery rules
• Best practices

Basic Bisect Workflow

git bisect start
git bisect bad
git bisect good <commit-hash>

# test current checkout
git bisect good   # if bug is NOT present
git bisect bad    # if bug IS present

git bisect reset

Finding the Good Commit

git log --oneline -20
git log --oneline --since="2024-01-01" --until="2024-01-15"
git log --oneline --author="name"
git tag --list

Automated Bisect

git bisect start
git bisect bad HEAD
git bisect good v1.0.0
git bisect run ./test-bug.sh

Rules for test-bug.sh:

• exit 0 when the current commit is good
• exit non-zero when the bug is present
• keep the verification method identical on every step

Complex Cases

git bisect skip
git bisect start -- src/components/
git bisect log > bisect-log.txt
git bisect replay bisect-log.txt

Best Practices

• Ensure the bug is reproducible before starting.
• Prefer a quick deterministic test.
• Stash or commit local changes first.
• Use skip for commits that do not build.
• Verify the final culprit commit before reporting it as causal.