Every archive import was failing immediately with "AssertionError:
daemonic processes are not allowed to have children" (operator-flagged
2026-05-30 — import_archive_file crashes in 49ms with the assertion).
Celery's prefork pool runs tasks in daemon processes; Python's
multiprocessing module refuses to let daemons spawn children, which is
exactly what probe_archive was doing via mp.get_context("spawn")
.Process. The Layer-3 crash-isolation feature added 2026-05-28 was
effectively a hard-blocker on the very import path it was meant to
protect.
Switched probe_archive to subprocess.run — no daemon restriction, still
isolates the probe (a probe segfault/OOM exits non-zero, doesn't kill
the worker). The probe body lifted to a tiny runner module
(_archive_probe_runner) that imports the unchanged _run_probe helper
and prints a single JSON line; parent parses stdout, returns the
ProbeResult exactly as before (timeout, signal, OOM, clean-rejection,
ok — all preserved).
cwd for the subprocess is the repo root derived from __file__ parents
so `python -m backend.app.utils._archive_probe_runner` resolves both in
the Celery container and pytest, regardless of where the worker was
launched.
Test refactor: test_archive_probe_target_bomb_guard →
test_run_probe_bomb_guard. Same in-process call to the (renamed) probe
body so the monkeypatched cap still takes effect; the real subprocess
path is exercised by the existing test_probe_archive_valid_zip /
test_probe_archive_corrupt_zip_clean_rejection tests.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen
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