"""Prune stale build artifacts and build cache from the shared volume. Eval results are sacrosanct: this only ever touches the build-related top-leveldirectories listed in `PRUNABLE_DIRS`. `runs/` (the eval outputs) is never inthat set and is never walked, so a bug here cannot delete results. The logic is pure-filesystem (no Modal dependency) so it can be unit-testedagainst a temporary directory; `modal_app` wraps it with volume reload/commit anda daily schedule.""" from __future__ import annotations import datetimeimport shutilimport timefrom pathlib import Pathfrom typing import Any # The ONLY top-level volume directories cleanup may modify. Eval results live in# runs/, which is deliberately absent here.PRUNABLE_DIRS = frozenset({"builds", "build-locks", "tmp"}) DEFAULT_BUILD_RETENTION_DAYS = 14.0DEFAULT_LOCK_TTL_HOURS = 6.0DEFAULT_TMP_MAX_AGE_HOURS = 24.0  def _age_days(path: Path) -> float:    try:        return (time.time() - path.stat().st_mtime) / 86400.0    except OSError:        return 0.0  def prune_artifacts(    data_root: Path | str,    *,    dry_run: bool = False,    build_retention_days: float = DEFAULT_BUILD_RETENTION_DAYS,    lock_ttl_hours: float = DEFAULT_LOCK_TTL_HOURS,    tmp_max_age_hours: float = DEFAULT_TMP_MAX_AGE_HOURS,) -> dict[str, Any]:    data_root = Path(data_root)    removed: dict[str, list[Any]] = {        "builds": [],        "locks": [],        "tmp": [],    }     # 1. Stale content-addressed builds, aged by their READY marker (or the dir    #    itself for never-finished builds). Cheap to rebuild on demand.    builds_dir = data_root / "builds"    if builds_dir.is_dir():        for build_dir in sorted(builds_dir.iterdir()):            if not build_dir.is_dir():                continue            ready = build_dir / "READY"            age = _age_days(ready if ready.exists() else build_dir)            if age > build_retention_days:                removed["builds"].append(                    {"build_id": build_dir.name, "age_days": round(age, 1)}                )                if not dry_run:                    shutil.rmtree(build_dir, ignore_errors=True)     # 2. Orphaned single-flight build leases left by crashed builds.    locks_dir = data_root / "build-locks"    if locks_dir.is_dir():        for lock in sorted(locks_dir.glob("*.json")):            if _age_days(lock) * 24.0 > lock_ttl_hours:                removed["locks"].append(lock.name)                if not dry_run:                    lock.unlink(missing_ok=True)     # 3. Orphaned temp build dirs from failed/raced builds.    tmp_builds = data_root / "tmp" / "builds"    if tmp_builds.is_dir():        for entry in sorted(tmp_builds.iterdir()):            if _age_days(entry) * 24.0 > tmp_max_age_hours:                removed["tmp"].append(entry.name)                if not dry_run:                    if entry.is_dir():                        shutil.rmtree(entry, ignore_errors=True)                    else:                        entry.unlink(missing_ok=True)     return {        "dry_run": dry_run,        "at": datetime.datetime.now(datetime.timezone.utc).isoformat(),        "removed": removed,        "counts": {key: len(value) for key, value in removed.items()},    }