Append two sections to the ria-removal plan capturing the
2026-07-02 hang episode + the resulting design pivot.
Regression writeup: the full-suite hang on
`test_tractor_cancels_aio` root-caused to the step-A reaper
hoist (`5cd190c5`), not the B2 handler merge. The happy-path
`_reap_ria_portals()` parks unbounded on `wait_for_result()`
after a user `portal.cancel_actor()`; the old spawn-backend
reaper raced `soft_kill()`'s scope-cancel, the hoist dropped
it. Records the `proc.poll()` death-watch fix + why poll (not
the event `wait_func`) bc `soft_kill` already awaits
`proc.sentinel` (a 2nd `wait_readable` -> `BusyResourceError`).
Pause writeup: user's insight that the hoist landed in the
wrong scope — result-waiting belongs in the `to_actor`
one-shot scope (`_invoke_in_subactor()`), beside `an` + a
local task-nursery + cancel-scope, where bounding the wait is
trivial + the hang dissolves. So the poll fix is likely
SUPERSEDED (flagged do-not-land); the anti-hang guard commit
(`d1fb4a1a`) stays red-first per the failing-test convention.
(this patch was generated in some part by `claude-code` using
`claude-opus-4-8` (`anthropic`))
Split from the step-B2 code commit to keep the runtime diff
free of `ai/` meta noise,
- `ai/conc-anal/ria_nursery_removal_plan.md`: add a "Step-B2
outcome" section — the dead-outer-`raise` trace, why the
merge is behavior-preserving, and the gate results.
- `ai/prompt-io/claude/20260702T222544Z_9201a2ed_*`: NLNet
provenance (log + unedited raw) for the step-B2 work.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Split from the step-B code commit to keep the runtime diff
free of `ai/` meta noise,
- `ai/conc-anal/ria_nursery_removal_plan.md`: add a "Step-B
outcome" section — the empty-nursery collapse, why it's
behavior-preserving, the deliberate handler-merge deferral,
and the targeted-gate result.
- `ai/prompt-io/claude/20260702T172233Z_5cd190c5_*`: NLNet
provenance (log + unedited raw) for the step-B work.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Split from the step-A code commit to keep the runtime diff
free of `ai/` meta noise,
- `ai/conc-anal/ria_nursery_removal_plan.md`: agent-verified
machinery map + 3-step (A/B/C) design + probe history
(reap-relocation deadlock -> sequencing fix -> bound
tighten) + risk register for the `._ria_nursery` excision.
- `ai/prompt-io/claude/20260702T165806Z_a34aaf98_*`: NLNet
provenance (log + unedited raw) for the step-A work.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
trio 0.29 → 0.33 lock bump (c7741bba) slowed the
depth=3 cancel-cascade in `test_nested_multierrors`
from <6s to ~7-8s; the 6s deadline was firing and its
`Cancelled(source='deadline')` (trio 0.33's new
cancel-reason metadata) collapsed a BEG branch,
breaking the `RemoteActorError` assertion downstream.
- Split the `('trio', _)` case-match into per-depth
arms: `('trio', 1)` keeps 6s (still finishes in
~3s); `('trio', 3)` → 12s.
- Updated inline NOTE explains the version pivot +
links the tracking issue
`ai/conc-anal/trio_033_cancel_cascade_slowdown_depth3_issue.md`.
- Existing MTF/`subint_forkserver` budgets unchanged.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit ea67f1b67b)
(cherry picked from commit 57b3ea59ea)
New `ai/conc-anal/spawn_time_boot_death_dup_name_issue.md`
documenting the spawn-time rc=2 race under rapid
same-name spawning against a forkserver + registrar
— the `wait_for_peer_or_proc_death` helper now surfaces
the death instead of parking forever on the handshake
wait.
Also,
- extract inline `xfail` into module-level
`_DOGGY_BOOT_RACE_XFAIL` marker.
- apply it to `n_dups=8` too (previously bare) bc
larger N widens the race window enough to fire
occasionally.
- link to tracking issue #456.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit 92443dc4ef)
With a seminal patch fixing `trio`'s `WakeupSocketpair.drain()` which
can busy-loop due to lack of handling `EOF`.
New `tractor.trionics.patches` subpkg housing defensive monkey-patches
for upstream `trio` bugs we've encountered while running `tractor`
— particularly as of recent, fork-survival edge cases that haven't been
filed/fixed upstream yet. Each patch is idempotent, version-gated via
`is_needed()`, and carries a `# REMOVE WHEN:` marker pointing at the
upstream release whose adoption allows deletion.
Subpkg layout + per-patch contract documented in
`tractor/trionics/patches/README.md` — `apply()` / `is_needed()`
/ `repro()` API, registry pattern via `_PATCHES` in `__init__.py`,
single-call entry point `apply_all()`.
First patch, `_wakeup_socketpair`:
- `trio`'s `WakeupSocketpair.drain()` loops on `recv(64KB)` and exits
ONLY on `BlockingIOError`, NEVER on `recv() == b''` (peer-closed FIN).
- under `fork()`-spawning backends the COW-inherited socketpair fds
& `_close_inherited_fds()` teardown can leave a `WakeupSocketpair`
instance whose write-end is closed, and `drain()` then **spins forever
in C with no Python checkpoints**,
- this obviously burns 100% CPU and no signal delivery.
Standalone repro:
from trio._core._wakeup_socketpair import WakeupSocketpair
ws = WakeupSocketpair()
ws.write_sock.close()
ws.drain() # spins forever
Patch is one-line — break the drain loop on b'' EOF.
Manifested as two distinct test failures:
- `tests/test_multi_program.py::test_register_duplicate_name` hung at
100% CPU on the busy-loop directly (fork child's worker thread)
- `tests/test_infected_asyncio.py::test_aio_simple_error` Mode-A
deadlock — busy-loop wedged trio's scheduler inside `start_guest_run`,
both threads parked in `epoll_wait`, no TCP connect-back to parent
ever happened.
Same patch fixes both. Restored 99.7% pass rate on full
suite under `--spawn-backend=main_thread_forkserver`
(was hanging indefinitely before).
Wired into `tractor._child._actor_child_main` via `apply_all()` BEFORE
any trio runtime init. Harmless on non-fork backends.
Conc-anal write-ups, including strace + py-spy evidence:
- `ai/conc-anal/trio_wakeup_socketpair_busy_loop_under_fork_issue.md`
- `ai/conc-anal/infected_asyncio_under_main_thread_forkserver_hang_issue.md`
Regression tests in `tests/trionics/test_patches.py`: each test asserts
(a) the bug exists pre-patch (or is fixed upstream — skip cleanly), (b)
the patch fixes it with a SIGALRM wall-clock cap so a regression hangs
loud instead of silently.
TODO:
- [ ] file the upstream `python-trio/trio` issue + PR.
- [ ] use the `repro()` callable in `_wakeup_socketpair.py` IS the issue
body's evidence section.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit 0ef549fadb)
(factored: dropped spawn-backend-only paths: ai/conc-anal/infected_asyncio_under_main_thread_forkserver_hang_issue.md)
Document the intermittent connect-refused failure in the registrar
daemon test — root cause is the `daemon` fixture's blind `time.sleep()`
readiness gate racing against the subproc's `bind()`/ `listen()`
completion. Distinct from the cancel- cascade `TooSlowError` flake
class.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit 29f9928524)
(cherry picked from commit 15c3b670e1)
Gud Boi