Show HN: Git bayesect – Bayesian Git bisection for non-deterministic bugs

Summary

Bayesian git bisection! Use this to detect changes in likelihoods of events, for instance, to isolate a commit where a slightly flaky test became very flaky. You don't need to know the likelihoods (although you can provide priors), just that something has changed at some point in some direction Or: uv tool install git_bayesect git_bayesect uses Bayesian inference to identify the commit introducing a change, with commit selection performed via greedy minimisation of expected entropy, and using a Beta-Bernoulli conjugacy trick while calculating posterior probabilities to make handling unknown failure rates tractable. See https://hauntsaninja.github.io/git_bayesect.html for a write up. Start a Bayesian bisection: git bayesect start --old $COMMIT Record an observation on the current commit: Or on a specific commit: git bayesect pass --commit $COMMIT Check the overall status of the bisection: Reset: Set the prior for a given commit: git bayesect prior --commit $COMMIT --weight 10 Set prior for all commits based on filenames: git bayesect priors_from_filenames --filenames-callback "return 10 if any('suspicious' in f for f in filenames) else 1" Set prior for all commits based on the text in the commit message + diff: git bayesect priors_from_text --text-callback "return 10 if 'timeout' in text.lower() else 1" Get a log of commands to let you reconstruct the state: Undo the last observation: Run the bisection automatically using a command to make observations: Checkout the best commmit to test: This repository contains a little demo, in case you'd like to play around: # Create a fake repository with a history to bayesect over python scripts/generate_fake_repo.py cd fake_repo # The fake repo contains a script called flaky.py # This is a simple script that fails some fraction of the time # At some point in the history of the repo, that fraction was changed python flaky.py git log --oneline # Start the bayesection OLD_COMMIT=$(git rev-list HEAD --reverse | head -n 2 | tail -n ...