Isolation and caching¶

One bare mirror per canonical repository identity lives below <cache>/repos/<blake3>. Every worker attaches a detached worktree to that mirror. Worktree registration changes are serialized, while setup and run hooks remain parallel. Cleanup always removes and prunes registrations.

Per-commit environment directories are keyed by repository, SHA, and setup hook. A changed run hook can therefore reuse expensive installations. Evaluation results use a broader key containing the repository, SHA, setup, run/oracle configuration, retries, and pins. --no-cache bypasses completed evaluation reads without discarding installed environments.

Fixed companion dependencies ([[pins]]) are installed once into shared pin environments. Candidate hooks receive their paths through BISECTRUNK_PIN_ENVS.