[chaliy]

What changed

The CPython guest no longer reseeds random on every python3 call. The snapshot's module instance seeds itself from os.urandom the first time a call uses it, then turns back into a plain Random.

Why

Most calls never touch random, and the reseed was ~0.2 ms of per-call driver work on Pulley. Per-tenant randomness is unchanged: every call that draws numbers is still seeded fresh.

Before

python_call/cpython/pass: 3.7 ms. random reseeded in _refresh_process_state on every call.

After

python_call/cpython/pass: 3.49 ms (criterion, −7%, p = 0.00). print within noise (4.37 ms). New test lazy_random_seed_covers_every_entry_point checks that every module entry point (random, randint, choice, shuffle, getrandbits, getstate, seed, setstate, randbytes, ...) differs across calls and that seed(n) stays deterministic.

Risk

Low. Calling the C base method directly (_random.Random.random(random._inst)) skips the seed and sees the snapshot state; documented in the driver. random is not a CSPRNG.

Checklist

• cargo test -p bashkit --features cpython --test integration -- cpython (112 passed)
• cargo fmt --check
• Knowledge updated (cpython-wasm.md, log)

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	bashkit	de56d2b	Commit Preview URL Branch Preview URL	Oct 07 2026, 05:17 AM