Two coordinated improvements to the `subint_forkserver` backend:
1. Replace `trio.to_thread.run_sync(os.waitpid, ...,
abandon_on_cancel=False)` in `_ForkedProc.wait()`
with `trio.lowlevel.wait_readable(pidfd)`. The
prior version blocked a trio cache thread on a
sync syscall — outer cancel scopes couldn't
unwedge it when something downstream got stuck.
Same pattern `trio.Process.wait()` and
`proc_waiter` (the mp backend) already use.
2. Drop the `@pytest.mark.xfail(strict=True)` from
`test_orphaned_subactor_sigint_cleanup_DRAFT` —
the test now PASSES after 0cd0b633 (fork-child
FD scrub). Same root cause as the nested-cancel
hang: inherited IPC/trio FDs were poisoning the
child's event loop. Closing them lets SIGINT
propagation work as designed.
Deats,
- `_ForkedProc.__init__` opens a pidfd via
`os.pidfd_open(pid)` (Linux 5.3+, Python 3.9+)
- `wait()` parks on `trio.lowlevel.wait_readable()`,
then non-blocking `waitpid(WNOHANG)` to collect
the exit status (correct since the pidfd signal
IS the child-exit notification)
- `ChildProcessError` swallow handles the rare race
where someone else reaps first
- pidfd closed after `wait()` completes (one-shot
semantics) + `__del__` belt-and-braces for
unexpected-teardown paths
- test docstring's `@xfail` block replaced with a
`# NOTE` comment explaining the historical
context + cross-ref to the conc-anal doc; test
remains in place as a regression guard
The two changes are interdependent — the
cancellable `wait()` matters for the same nested-
cancel scenarios the FD scrub fixes, since the
original deadlock had trio cache workers wedged in
`os.waitpid` swallowing the outer cancel.
(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 c20b05e181)
Implements fix-direction (1)/blunt-close-all-FDs from
b71705bd (`subint_forkserver` nested-cancel hang
diag), targeting the multi-level cancel-cascade
deadlock in
`test_nested_multierrors[subint_forkserver]`.
The diagnosis doc voted for surgical FD cleanup via
`actor.ipc_server` handle as the cleanest approach,
but going blunt is actually the right call: after
`os.fork()`, the child immediately enters
`_actor_child_main()` which opens its OWN IPC
sockets / wakeup-fd / epoll-fd / etc. — none of the
parent's FDs are needed. Closing everything except
stdio is safe AND defends against future
listener/IPC additions to the parent inheriting
silently into children.
Deats,
- new `_close_inherited_fds(keep={0,1,2}) -> int`
helper. Linux fast-path enumerates `/proc/self/fd`;
POSIX fallback uses `RLIMIT_NOFILE` range. Matches
the stdlib `subprocess._posixsubprocess.close_fds`
strategy. Returns close-count for sanity logging
- wire into `fork_from_worker_thread._worker()`'s
post-fork child prelude — runs immediately after
the pid-pipe `os.close(rfd/wfd)`, before the user
`child_target` callable executes
- docstring cross-refs the diagnosis doc + spells
out the FD-inheritance-cascade mechanism and why
the close-all approach is safe for our spawn shape
Validation pending: re-run `test_nested_multierrors[subint_forkserver]`
to confirm the deadlock is gone.
(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 9993db0193)
Major rewrite of
`subint_forkserver_test_cancellation_leak_issue.md`
after empirical investigation revealed the earlier
"descendant-leak + missing tree-kill" diagnosis
conflated two unrelated symptoms:
1. **5-zombie leak holding `:1616`** — turned out to
be a self-inflicted cleanup bug: `pkill`-ing a bg
pytest task (SIGTERM/SIGKILL, no SIGINT) skipped
the SC graceful cancel cascade entirely. Codified
the real fix — SIGINT-first ladder w/ bounded
wait before SIGKILL — in e5e2afb5 (`run-tests`
SKILL) and
`feedback_sc_graceful_cancel_first.md`.
2. **`test_nested_multierrors[subint_forkserver]`
hangs indefinitely** — the actual backend bug,
and it's a deadlock not a leak.
Deats,
- new diagnosis: all 5 procs are kernel-`S` in
`do_epoll_wait`; pytest-main's trio-cache workers
are in `os.waitpid` waiting for children that are
themselves waiting on IPC that never arrives —
graceful `Portal.cancel_actor` cascade never
reaches its targets
- tree-structure evidence: asymmetric depth across
two identical `run_in_actor` calls — child 1
(3 threads) spawns both its grandchildren; child 2
(1 thread) never completes its first nursery
`run_in_actor`. Smells like a race on fork-
inherited state landing differently per spawn
ordering
- new hypothesis: `os.fork()` from a subactor
inherits the ROOT parent's IPC listener FDs
transitively. Grandchildren end up with three
overlapping FD sets (own + direct-parent + root),
so IPC routing becomes ambiguous. Predicts bug
scales with fork depth — matches reality: single-
level spawn works, multi-level hangs
- ruled out: `_ForkedProc.kill()` tree-kill (never
reaches hard-kill path), `:1616` contention (fixed
by `reg_addr` fixture wiring), GIL starvation
(each subactor has its own OS process+GIL),
child-side KBI absorption (`_trio_main` only
catches KBI at `trio.run()` callsite, reached
only on trio-loop exit)
- four fix directions ranked: (1) blanket post-fork
`closerange()`, (2) `FD_CLOEXEC` + audit,
(3) targeted FD cleanup via `actor.ipc_server`
handle, (4) `os.posix_spawn` w/ `file_actions`.
Vote: (3) — surgical, doesn't break the "no exec"
design of `subint_forkserver`
- standalone repro added (`spawn_and_error(breadth=
2, depth=1)` under `trio.fail_after(20)`)
- stopgap: skip `test_nested_multierrors` + multi-
level-spawn tests under the backend via
`@pytest.mark.skipon_spawn_backend(...)` until
fix lands
Killing the "tree-kill descendants" fix-direction
section: it addressed a bug that didn't exist.
(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 35da808905)
New `ai/conc-anal/
subint_forkserver_test_cancellation_leak_issue.md`
captures a descendant-leak surfaced while wiring
`subint_forkserver` into the full test matrix:
running `tests/test_cancellation.py` under
`--spawn-backend=subint_forkserver` reproducibly
leaks **exactly 5** `subint-forkserv` comm-named
child processes that survive session exit, each
holding a `LISTEN` on `:1616` (the tractor default
registry addr) — and therefore poisons every
subsequent test session that defaults to that addr.
Deats,
- TL;DR + ruled-out checks confirming the procs are
ours (not piker / other tractor-embedding apps) —
`/proc/$pid/cmdline` + cwd both resolve to this
repo's `py314/` venv
- root cause: `_ForkedProc.kill()` is PID-scoped
(plain `os.kill(SIGKILL)` to the direct child),
not tree-scoped — grandchildren spawned during a
multi-level cancel test get reparented to init and
inherit the registry listen socket
- proposed fix directions ranked: (1) put each
forkserver-spawned subactor in its own process-
group (`os.setpgrp()` in fork-child) + tree-kill
via `os.killpg(pgid, SIGKILL)` on teardown,
(2) `PR_SET_CHILD_SUBREAPER` on root, (3) explicit
`/proc/<pid>/task/*/children` walk. Vote: (1) —
POSIX-standard, aligns w/ `start_new_session=True`
semantics in `subprocess.Popen` / trio's
`open_process`
- inline reproducer + cleanup recipe scoped to
`$(pwd)/py314/bin/python.*pytest.*spawn-backend=
subint_forkserver` so cleanup doesn't false-flag
unrelated tractor procs (consistent w/
`run-tests` skill's zombie-check guidance)
Stopgap hygiene fix (wiring `reg_addr` through the 5
leaky tests in `test_cancellation.py`) is incoming as
a follow-up — that one stops the blast radius, but
zombies still accumulate per-run until the real
tree-kill fix lands.
(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 e3f4f5a387)
Follow-up to 72d1b901 (was prev commit adding `debug_mode` for
`subint_forkserver`): that commit wired the runtime-side
`subint_forkserver` SpawnSpec-recv gate in `Actor._from_parent`, but the
`subint_forkserver_proc` child-target was still passing
`spawn_method='trio'` to `_trio_main` — so `Actor.pformat()` / log lines
would report the subactor as plain `'trio'` instead of the actual
parent-side spawn mechanism. Flip the label to `'subint_forkserver'`.
(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 e31eb8d7c9)
Empirical follow-up to the xfail'd orphan-SIGINT test:
the hang is **not** "trio can't install a handler on a
non-main thread" (the original hypothesis from the
`child_sigint` scaffold commit). On py3.14:
- `threading.current_thread() is threading.main_thread()`
IS True post-fork — CPython re-designates the
fork-inheriting thread as "main" correctly
- trio's `KIManager` SIGINT handler IS installed in the
subactor (`signal.getsignal(SIGINT)` confirms)
- the kernel DOES deliver SIGINT to the thread
But `faulthandler` dumps show the subactor wedged in
`trio/_core/_io_epoll.py::get_events` — trio's
wakeup-fd mechanism (which turns SIGINT into an epoll-wake)
isn't firing. So the `except KeyboardInterrupt` at
`tractor/spawn/_entry.py::_trio_main:164` — the runtime's
intentional "KBI-as-OS-cancel" path — never fires.
Deats,
- new `ai/conc-anal/subint_forkserver_orphan_sigint_hang_issue.md`
(+385 LOC): full writeup — TL;DR, symptom reproducer,
the "intentional cancel path" the bug defeats,
diagnostic evidence (`faulthandler` output +
`getsignal` probe), ruled-out hypotheses
(non-main-thread issue, wakeup-fd inheritance,
KBI-as-trio-check-exception), and fix directions
- `test_orphaned_subactor_sigint_cleanup_DRAFT` xfail
`reason` + test docstring rewritten to match the
refined understanding — old wording blamed the
non-main-thread path, new wording points at the
`epoll_wait` wedge + cross-refs the new conc-anal doc
- `_subint_forkserver` module docstring's
`child_sigint='trio'` bullet updated: now notes trio's
handler is already correctly installed, so the flag may
end up a no-op / doc-only mode once the real root cause
is fixed
Closing the gap aligns with existing design intent (make
the already-designed "KBI-as-OS-cancel" behavior actually
fire), not a new feature.
(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 a72deef709)
Add configuration surface for future child-side SIGINT
plumbing in `subint_forkserver_proc` without wiring up the
actual trio-native SIGINT bridge — lifting one entry-guard
clause will flip the `'trio'` branch live once the
underlying fork-prelude plumbing is implemented.
Deats,
- new `ChildSigintMode = Literal['ipc', 'trio']` type +
`_DEFAULT_CHILD_SIGINT = 'ipc'` module-level default.
Docstring block enumerates both:
- `'ipc'` (default, currently the only implemented mode):
no child-side SIGINT handler — `trio.run()` is on the
fork-inherited non-main thread where
`signal.set_wakeup_fd()` is main-thread-only, so
cancellation flows exclusively via the parent's
`Portal.cancel_actor()` IPC path. Known gap: orphan
children don't respond to SIGINT
(`test_orphaned_subactor_sigint_cleanup_DRAFT`)
- `'trio'` (scaffolded only): manual SIGINT → trio-cancel
bridge in the fork-child prelude so external Ctrl-C
reaches stuck grandchildren even w/ a dead parent
- `subint_forkserver_proc` pulls `child_sigint` out of
`proc_kwargs` (matches how `trio_proc` threads config to
`open_process`, keeps `start_actor(proc_kwargs=...)` as
the ergonomic entry point); validates membership + raises
`NotImplementedError` for `'trio'` at the backend-entry
guard
- `_child_target` grows a `match child_sigint:` arm that
slots in the future `'trio'` impl without restructuring
— today only the `'ipc'` case is reachable
- module docstring "Still-open work" list grows a bullet
pointing at this config + the xfail'd orphan-SIGINT test
No behavioral change on the default path — `'ipc'` is the
existing flow. Scaffolding only.
(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 dcd5c1ff40)
Tier-4 test `test_orphaned_subactor_sigint_cleanup_DRAFT`
documents an empirical SIGINT-delivery gap in the
`subint_forkserver` backend: when the parent dies via
`SIGKILL` (no IPC `Portal.cancel_actor()` possible) and
`SIGINT` is sent to the orphan child, the child DOES NOT
unwind — CPython's default `KeyboardInterrupt` is delivered
to `threading.main_thread()`, whose tstate is dead in the
post-fork child bc fork inherited the worker thread, not
main. Trio running on the fork-inherited worker thread
therefore never observes the signal. Marked
`xfail(strict=True)` so the mark flips to XPASS→fail once
the backend grows explicit SIGINT plumbing.
Deats,
- harness runs the failure-mode sequence out-of-process:
1. harness subprocess runs a fresh Python script
that calls `try_set_start_method('subint_forkserver')`
then opens a root actor + one `sleep_forever` subactor
2. parse `PARENT_READY=<pid>` + `CHILD_PID=<pid>` markers
off harness `stdout` to confirm IPC handshake
completed
3. `SIGKILL` the parent, `proc.wait()` to reap the
zombie (otherwise `os.kill(pid, 0)` keeps reporting
it alive)
4. assert the child survived the parent-reap (i.e. was
actually orphaned, not reaped too) before moving on
5. `SIGINT` the orphan child, poll `os.kill(child_pid, 0)`
every 100ms for up to 10s
- supporting helpers: `_read_marker()` with per-proc
bytes-buffer to carry partial lines across calls,
`_process_alive()` liveness probe via `kill(pid, 0)`
- Linux-only via `platform.system() != 'Linux'` skip —
orphan-reparenting semantics don't generalize to
other platforms
- port offset (`reg_addr[1] + 17`) so the harness listener
doesn't race concurrently-running backend tests
- best-effort `finally:` cleanup: `SIGKILL` any still-alive
pids + `proc.kill()` + bounded `proc.wait()` to avoid
leaking orphans across the session
Also, tier-4 header comment documents the cross-backend
generalization path: applicable to any multi-process
backend (`trio`, `mp_spawn`, `mp_forkserver`,
`subint_forkserver`), NOT to plain `subint` (in-process
subints have no orphan OS-child). Move path: lift
harness into `tests/_orphan_harness.py`, parametrize on
session `_spawn_method`, add
`skipif _spawn_method == 'subint'`.
(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 76605d5609)
`os.fork()` inherits the parent's entire memory image,
including `tractor.runtime._state` globals that encode
"this process is the root actor" — `_runtime_vars`'s
`_is_root=True`, pre-populated `_root_mailbox` +
`_registry_addrs`, and the parent's `_current_actor`
singleton.
A fresh `exec`-based child starts with those globals at
their module-level defaults (all falsey/empty). The
forkserver child needs to match that shape BEFORE calling
`_actor_child_main()`, otherwise `Actor.__init__()` takes
the `is_root_process() == True` branch and pre-populates
`self.enable_modules`, which then trips
`assert not self.enable_modules` at the top of
`Actor._from_parent()` on the subsequent parent→child
`SpawnSpec` handshake.
Fix: at the start of `_child_target`, null
`_state._current_actor` and overwrite `_runtime_vars` with
a cold-root blank (`_is_root=False`, empty mailbox/addrs,
`_debug_mode=False`) before `_actor_child_main()` runs.
Found-via: `test_subint_forkserver_spawn_basic` hitting
the `enable_modules` assert on child-side runtime boot.
(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 63ab7c986b)
Promote `_subint_forkserver` from primitives-only into a
registered spawn backend: `'subint_forkserver'` is now a
`SpawnMethodKey` literal, dispatched via `_methods` to
the new `subint_forkserver_proc()` target, feature-gated
under the existing `subint`-family py3.14+ case, and
selectable via `--spawn-backend=subint_forkserver`.
Deats,
- new `subint_forkserver_proc()` spawn target in
`_subint_forkserver`:
- mirrors `trio_proc()`'s supervision model — real OS
subprocess so `Portal.cancel_actor()` + `soft_kill()`
on graceful teardown, `os.kill(SIGKILL)` on hard-reap
(no `_interpreters.destroy()` race to fuss over bc the
child lives in its own process)
- only real diff from `trio_proc` is the spawn mechanism:
fork from a main-interp worker thread via
`fork_from_worker_thread()` (off-loaded to trio's
thread pool) instead of `trio.lowlevel.open_process()`
- child-side `_child_target` closure runs
`tractor._child._actor_child_main()` with
`spawn_method='trio'` — the child is a regular trio
actor, "subint_forkserver" names how the parent
spawned, not what the child runs
- new `_ForkedProc` class — thin `trio.Process`-compatible
shim around a raw OS pid: `.poll()` via
`waitpid(WNOHANG)`, async `.wait()` off-loaded to a trio
cache thread, `.kill()` via `SIGKILL`, `.returncode`
cached for repeat calls. `.stdin`/`.stdout`/`.stderr`
are `None` (fork-w/o-exec inherits parent FDs; we don't
marshal them) which matches `soft_kill()`'s `is not None`
guards
Also, new backend-tier test
`test_subint_forkserver_spawn_basic` drives the registered
backend end-to-end via `open_root_actor` + `open_nursery` +
`run_in_actor` w/ a trivial portal-RPC round-trip. Uses a
`forkserver_spawn_method` fixture to flip
`_spawn_method`/`_ctx` for the test's duration + restore on
teardown (so other session-level tests don't observe the
global flip). Test module docstring reworked to describe
the three tiers now covered: (1) primitive-level, (2)
parent-trio-driven primitives, (3) full registered backend.
Status: still-open work (tracked on `tractor#379`) doc'd
inline in the module docstring — no cancel/hard-kill stress
coverage yet, child-side subint-hosted root runtime still
future (gated on `msgspec#563`), thread-hygiene audit
pending the same unblock.
(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 26914fde75)
Follow-up tracker companion to the module-docstring TODO
added in `372a0f32`. Catalogs why `_subint_forkserver`'s
two "non-trio thread" constraints
(`fork_from_worker_thread()` +
`run_subint_in_worker_thread()` both allocating dedicated
`threading.Thread`s; test helper named
`run_fork_in_non_trio_thread`) exist today, and which of
them would dissolve once msgspec PEP 684 support ships
(`msgspec#563`) and tractor flips to isolated-mode subints.
Deats,
- three reasons enumerated for the current constraints:
- class-A GIL-starvation — **fixed** by isolated mode:
subints don't share main's GIL so abandoned-thread
contention disappears
- destroy race / tstate-recycling from `subint_proc` —
**unclear**: `_PyXI_Enter` + `_PyXI_Exit` are
cross-mode, so isolated doesn't obviously fix it;
needs empirical retest on py3.14 + isolated API
- fork-from-main-interp-tstate (the CPython-level
`_PyInterpreterState_DeleteExceptMain` gate) — the
narrow reason for using a dedicated thread; **probably
fixed** IF the destroy-race also resolves (bc trio's
cache threads never drove subints → clean main-interp
tstate)
- TL;DR table of which constraints unwind under each
resolution branch
- four-step audit plan for when `msgspec#563` lands:
- flip `_subint` to isolated mode
- empirical destroy-race retest
- audit `_subint_forkserver.py` — drop `non_trio`
qualifier / maybe inline primitives
- doc fallout — close the three `subint_*_issue.md`
siblings w/ post-mortem notes
Also, cross-refs the three sibling `conc-anal/` docs, PEPs
684 + 734, `msgspec#563`, and `tractor#379` (the overall
subint spawn-backend tracking issue).
(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 cf2e71d87f)
New pytest module `tests/spawn/test_subint_forkserver.py`
drives the forkserver primitives from inside a real
`trio.run()` in the parent — the runtime shape tractor will
actually use when we wire up a `subint_forkserver` spawn
backend proper. Complements the standalone no-trio-in-parent
`ai/conc-anal/subint_fork_from_main_thread_smoketest.py`.
Deats,
- new test pkg `tests/spawn/` (+ empty `__init__.py`)
- two tests, both `@pytest.mark.timeout(30, method='thread')`
for the GIL-hostage safety reason doc'd in
`ai/conc-anal/subint_sigint_starvation_issue.md`:
- `test_fork_from_worker_thread_via_trio` — parent-side
plumbing baseline. `trio.run()` off-loads forkserver
prims via `trio.to_thread.run_sync()` + asserts the
child reaps cleanly
- `test_fork_and_run_trio_in_child` — end-to-end: forked
child calls `run_subint_in_worker_thread()` with a
bootstrap str that does `trio.run()` in a fresh subint
- both tests wrap the inner `trio.run()` in a
`dump_on_hang()` for post-mortem if the outer
`pytest-timeout` fires
- intentionally NOT using `--spawn-backend` — the tests
drive the primitives directly rather than going through
tractor's spawn-method registry (which the forkserver
isn't plugged into yet)
Also, rename `run_trio_in_subint()` →
`run_subint_in_worker_thread()` for naming consistency with
the sibling `fork_from_worker_thread()`. The action is really
"host a subint on a worker thread", not specifically "run
trio" — trio just happens to be the typical payload.
Propagate the rename to the smoketest.
Further, add a "TODO — cleanup gated on msgspec PEP 684
support" section to the `_subint_forkserver` module
docstring: flags the dedicated-`threading.Thread` design as
potentially-revisable once isolated-mode subints are viable
in tractor. Cross-refs `msgspec#563` + `tractor#379` and
points at an audit-plan conc-anal doc we'll add next.
(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 25e400d526)
The smoketest (prior commit) empirically validated the
"fork-from-main-interp-worker-thread" arch on py3.14. Promote
the validated primitives out of the `ai/conc-anal/` smoketest
into `tractor.spawn._subint_forkserver` so they can eventually
be wired into a real "subint forkserver" spawn backend.
Deats,
- new module `tractor/spawn/_subint_forkserver.py` (337 LOC):
- `fork_from_worker_thread(child_target, thread_name)` —
spawn a main-interp `threading.Thread`, call `os.fork()`
from it, shuttle the child pid back to main via a pipe
- `run_trio_in_subint(bootstrap, ...)` — post-fork helper:
create a fresh subint + drive `_interpreters.exec()` on
a dedicated worker thread running the `bootstrap` str
(typically imports `trio`, defines an async entry, calls
`trio.run()`)
- `wait_child(pid, expect_exit_ok)` — `os.waitpid()` +
pass/fail classification reusable from harness AND the
eventual real spawn path
- feature-gated py3.14+ via the public
`concurrent.interpreters` presence check; matches the gate
in `tractor.spawn._subint`
- module docstring doc's the CPython-block context
(cross-refs `_subint_fork` stub + the two `conc-anal/`
docs) and status: EXPERIMENTAL, not yet registered in
`_spawn._methods`
Also, refactor the smoketest
`ai/conc-anal/subint_fork_from_main_thread_smoketest.py` to
import the primitives from the new module rather than inline
its own copies. Keeps the smoketest and the tractor-side
impl in sync as the forkserver design evolves; the smoketest
remains a zero-`tractor`-runtime CPython-level check
(imports ONLY the three primitives, no runtime bring-up).
Status: next step is to drive these from a parent-side
`trio.run()` and hook the returned child pid into the normal
actor-nursery/IPC flow — then register `subint_forkserver`
as a `SpawnMethodKey` in `_spawn.py`.
(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 82332fbceb)
Standalone script to validate the "main-interp worker-thread
forkserver + subint-hosted trio" arch proposed as a workaround
to the CPython-level refusal doc'd in
`ai/conc-anal/subint_fork_blocked_by_cpython_post_fork_issue.md`.
Deliberately NOT a `tractor` test — zero `tractor` imports.
Uses `_interpreters` (private stdlib) + `os.fork()` directly so
pass/fail is a property of CPython alone, independent of our
runtime. Requires py3.14+.
Deats,
- four scenarios via `--scenario`:
- `control_subint_thread_fork` — the KNOWN-BROKEN case as a
harness sanity; if the child DOESN'T abort, our analysis
is wrong
- `main_thread_fork` — baseline sanity, must always succeed
- `worker_thread_fork` — architectural assertion: regular
`threading.Thread` attached to main interp calls
`os.fork()`; child should survive post-fork cleanup
- `full_architecture` — end-to-end: fork from a main-interp
worker thread, then in child create a subint driving a
worker thread running `trio.run()`
- exit code 0 on EXPECTED outcome (for `control_*` that means
"child aborted", not "child succeeded")
- each scenario prints a self-contained pass/fail banner; use
`os.waitpid()` of the parent + per-scenario status prints to
observe the child's fate
Also, log NLNet provenance for this session's three-sub-phase
work (py3.13 gate tightening, `pytest-timeout` + marker
refactor, `subint_fork` prototype → CPython-block finding).
Prompt-IO: ai/prompt-io/claude/20260422T200723Z_797f57c_prompt_io.md
(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 de4f470b6c)
Empirical finding: the WIP `subint_fork_proc` scaffold
landed in `cf0e3e6f` does *not* work on current CPython.
The `fork()` syscall succeeds in the parent, but the
CHILD aborts immediately during
`PyOS_AfterFork_Child()` →
`_PyInterpreterState_DeleteExceptMain()`, which gates
on the current tstate belonging to the main interp —
the child dies with `Fatal Python error: not main
interpreter`.
CPython devs acknowledge the fragility with an in-source
comment (`// Ideally we could guarantee tstate is running
main.`) but expose no user-facing hook to satisfy the
precondition — so the strategy is structurally dead until
upstream changes.
Rather than delete the scaffold, reshape it into a
documented dead-end so the next person with this idea
lands on the reason rather than rediscovering the same
CPython-level refusal.
Deats,
- Move `subint_fork_proc` out of `tractor.spawn._subint`
into a new `tractor.spawn._subint_fork` dedicated
module (153 LOC). Module + fn docstrings now describe
the blockage directly; the fn body is trimmed to a
`NotImplementedError` pointing at the analysis doc —
no more dead-code `bootstrap` sketch bloating
`_subint.py`.
- `_spawn.py`: keep `'subint_fork'` in `SpawnMethodKey`
+ the `_methods` dispatch so
`--spawn-backend=subint_fork` routes to a clean
`NotImplementedError` rather than "invalid backend";
comment calls out the blockage. Collapse the duplicate
py3.14 feature-gate in `try_set_start_method()` into a
combined `case 'subint' | 'subint_fork':` arm.
- New 337-line analysis:
`ai/conc-anal/subint_fork_blocked_by_cpython_post_fork_issue.md`.
Annotated walkthrough from the user-visible fatal
error down to the specific `Modules/posixmodule.c` +
`Python/pystate.c` source lines enforcing the refusal,
plus an upstream-report draft.
(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 0f48ed2eb9)
Experimental third spawn backend: use a fresh
sub-interpreter purely as a trio-free launchpad from
which to `os.fork()` + exec back into
`python -m tractor._child`. Per issue #379's
"fork()-workaround/hacks" thread.
Intent is to sidestep both,
- the trio+fork hazards hitting `trio_proc` (python- trio/trio#1614 et
al.), since the forking interp is guaranteed trio-free.
- the shared-GIL abandoned-thread hazards hitting `subint_proc`
(`ai/conc-anal/subint_sigint_starvation_issue.md`), since we don't
*stay* in the subint — it only lives long enough to call `os.fork()`
Downstream of the fork+exec, all the existing `trio_proc` plumbing is
reused verbatim: `ipc_server.wait_for_peer()`, `SpawnSpec`, `Portal`
yield, soft-kill.
Status: NOT wired up beyond scaffolding. The fn raises
`NotImplementedError` immediately; the `bootstrap` fork/exec string
builder and the `# TODO: orchestrate driver thread` block are kept
in-tree as deliberate dead code so the next iteration starts from
a concrete shape rather than a blank page.
Docstring calls out three open questions that need
empirical validation before wiring this up:
1. Does CPython permit `os.fork()` from a non-main
legacy subint?
2. Can the child stay fork-without-exec and
`trio.run()` directly from within the launchpad
subint?
3. How do `signal.set_wakeup_fd()` handlers and other
process-global state interact when the forking
thread is inside a subint?
(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 eee79a0357)
Add two more tests to the catalog in
`conc-anal/subint_sigint_starvation_issue.md` — same
signal-wakeup-fd-saturation fingerprint (abandoned legacy-subint driver
threads → shared-GIL starvation → `write() = EAGAIN` on the wakeup pipe
→ silent SIGINT drop), different load patterns.
Deats,
- `test_cancel_while_childs_child_in_sync_sleep[subint-False]`: nested
actor-tree + sync-sleeping grandchild. Under `trio`/`mp_*` the "zombie
reaper" is a subproc `SIGKILL`; no equivalent exists under subint, so
the grandchild persists in its abandoned driver thread. Often only
manifests under full-suite runs (earlier tests seed the
abandoned-thread pool).
- `test_multierror_fast_nursery[subint-25-0.5]`: 25 concurrent subactors
all go through teardown on the multierror. Bounded hard-kills run in
parallel — so the total budget is ~3s, not 3s × 25. Leaves 25
abandoned driver threads simultaneously alive, an extreme pressure
multiplier. `strace` shows several successful `write(16, "\2", 1) = 1`
(GIL round-robin IS giving main brief slices) before finally
saturating with `EAGAIN`.
Also include a `pstree -snapt <pid>` capture showing
16+ live `{subint-driver[<interp_id>}` threads at the
moment of hang — the direct GIL-contender population.
(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 f3cea714bc)
Add a hard process-level wall-clock bound on the two
known-hanging subint-backend tests so an unattended
suite run can't wedge indefinitely in either of the
hang classes doc'd in `ai/conc-anal/`.
Deats,
- New `testing` dep: `pytest-timeout>=2.3`.
- `test_stale_entry_is_deleted`:
`@pytest.mark.timeout(3, method='thread')`. The
`method='thread'` choice is deliberate —
`method='signal'` routes via `SIGALRM` which is
starved by the same GIL-hostage path that drops
`SIGINT` (see `subint_sigint_starvation_issue.md`),
so it'd never actually fire in the starvation case.
- `test_subint_non_checkpointing_child`: same
decorator, same reasoning (defense-in-depth over
the inner `trio.fail_after(15)`).
At timeout, `pytest-timeout` hard-kills the pytest
process itself — that's the intended behavior here;
the alternative is the suite never returning.
(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 189f4e3ffc)
(MTF-only portion: kept tests/test_subint_cancellation.py)
Log the `claude-opus-4-7` collab that produced `e92e3cd2` ("Doc `subint`
backend hang classes + arm `dump_on_hang`"). Substantive bc the two new
`ai/conc-anal/` docs were jointly authored — user framed the two-class
split + set candidate-fix ordering for the class-2 (Ctrl-C-able) hang;
claude drafted the prose and the test-side cross-linking comments.
`.raw.md` is in diff-ref mode — per-file pointers via `git diff
e92e3cd2~1..e92e3cd2 -- <path>` rather than re-embedding content that
already lives in `git log -p`.
Prompt-IO: ai/prompt-io/claude/20260420T192739Z_5e8cd8b2_prompt_io.md
(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 a65fded4c6)
Classify and write up the two distinct hang modes hit during Phase
B subint bringup (issue #379) so future triage doesn't re-derive them
from scratch.
Deats, two new `ai/conc-anal/` docs,
- `subint_sigint_starvation_issue.md`: abandoned legacy-subint thread
+ shared GIL → main trio loop starves → signal-wakeup-fd pipe fills
→ `SIGINT` silently dropped (`strace` shows `write() = EAGAIN` on the
wakeup-fd). Un- Ctrl-C-able. Structurally a CPython limit; blocked on
`msgspec` PEP 684 (jcrist/msgspec#563)
- `subint_cancel_delivery_hang_issue.md`: parent-side trio task parks on
an orphaned IPC channel after subint teardown — no clean EOF delivered
to the waiting receive. Ctrl-C-able (main loop iterates fine); OUR bug
to fix. Candidate fix: explicit parent-side channel abort in
`subint_proc`'s hard-kill teardown
Cross-link the docs from their test reproducers,
- `test_stale_entry_is_deleted` (→ starvation class): wrap
`trio.run(main)` in `dump_on_hang(seconds=20)` so a future regression
captures a stack dump. Kept un- skipped so the dump file is
inspectable
- `test_subint_non_checkpointing_child` (→ delivery class): extend
docstring with a "KNOWN ISSUE" block pointing at the analysis
(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 4a3254583b)
(MTF-only portion: kept ai/conc-anal/subint_cancel_delivery_hang_issue.md ai/conc-anal/subint_sigint_starvation_issue.md tests/test_subint_cancellation.py)
Lock in the escape-hatch machinery added to `tractor.spawn._subint`
during the Phase B.2/B.3 bringup (issue #379) so future stdlib
regressions or our own refactors don't silently re-introduce the
mid-suite hangs.
Deats,
- `test_subint_happy_teardown`: baseline — spawn a subactor, one portal
RPC, clean teardown. If this breaks, something's wrong unrelated to
the hard-kill shields.
- `test_subint_non_checkpointing_child`: cancel a subactor stuck in
a non-checkpointing Python loop (`threading.Event.wait()` releases the
GIL but never inserts a trio checkpoint). Validates the bounded-shield
+ daemon-driver-thread combo abandons the thread after
`_HARD_KILL_TIMEOUT`.
Every test is wrapped in `trio.fail_after()` for a deterministic
per-test wall-clock ceiling (an unbounded audit would defeat itself) and
arms `tractor.devx.dump_on_hang()` so a hang captures a stack dump
— pytest's stderr capture swallows `faulthandler` output by default.
Gated via `pytest.importorskip('concurrent.interpreters')` and
a module-level skip when `--spawn-backend` isn't `'subint'`.
(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 2ed5e6a6e8)
The private `_interpreters` C module ships since 3.13, but that vintage
wedges under our `threading.Thread` + multi-trio usage pattern
—> `_interpreters.exec()` silently never makes progress. 3.14 fixes it.
So gate on the presence of the public `concurrent.interpreters` wrapper
(3.14+ only) even tho we still call into the private module at runtime.
Deats,
- `try_set_start_method('subint')` error msg + `_subint` module
docstring/comments rewritten to document the 3.14 floor and why 3.13
can't work.
- `_subint._has_subints` gate now imports `concurrent.interpreters` (not
`_interpreters`) as the version sentinel.
Also, reshuffle `pyproject.toml` deps into
per-python-version `[tool.uv.dependency-groups]`:
- `subints` group: `msgspec>=0.21.0`, py>=3.14
- `eventfd` group: `cffi>=1.17.1`, py>=3.13,<3.14
- `sync_pause` group: `greenback`, py>=3.13,<3.14
(was in `devx`; moved out bc no 3.14 yet)
Bump top-level `msgspec>=0.20.0` too.
(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 34d9d482e4)
(MTF-only portion: kept tractor/spawn/_spawn.py tractor/spawn/_subint.py)
Unbounded `trio.CancelScope(shield=True)` at the
soft-kill and thread-join sites can wedge the parent
trio loop indefinitely when a stuck subint ignores
portal-cancel (e.g. bc the IPC channel is already
broken).
Deats,
- add `_HARD_KILL_TIMEOUT` (3s) module-level const
- wrap both shield sites with
`trio.move_on_after()` so we abandon a stuck
subint after the deadline
- flip driver thread to `daemon=True` so proc-exit
also isn't blocked by a wedged subint
- pass `abandon_on_cancel=True` to
`trio.to_thread.run_sync(driver_thread.join)`
— load-bearing for `move_on_after` to actually
fire
- log warnings when either timeout triggers
- improve `InterpreterError` log msg to explain
the abandoned-thread scenario
(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 99541feec7)
Log the `claude-opus-4-7` session that produced
the `_subint.py` dedicated-thread fix (`26fb8206`).
Substantive bc the patch was entirely AI-generated;
raw log also preserves the CPython-internals
research informing Phase B.3 hard-kill work.
Prompt-IO: ai/prompt-io/claude/20260418T042526Z_26fb820_prompt_io.md
(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 c041518bdb)
`trio.to_thread.run_sync(_interpreters.exec, ...)` runs `exec()` on
a cached worker thread — and when that thread is returned to the
cache after the subint's `trio.run()` exits, CPython still keeps
the subint's tstate attached to the (now idle) worker. Result: the
teardown `_interpreters.destroy(interp_id)` in the `finally` block
can block the parent's trio loop indefinitely, waiting for a tstate
release that only happens when the worker either picks up a new job
or exits.
Manifested as intermittent mid-suite hangs under
`--spawn-backend=subint` — caught by a
`faulthandler.dump_traceback_later()` showing the main thread stuck
in `_interpreters.destroy()` at `_subint.py:293` with only an idle
trio-cache worker as the other live thread.
Deats,
- drive the subint on a plain `threading.Thread` (not
`trio.to_thread`) so the OS thread truly exits after
`_interpreters.exec()` returns, releasing tstate and unblocking
destroy
- signal `subint_exited.set()` back to the parent trio loop from
the driver thread via `trio.from_thread.run_sync(...,
trio_token=...)` — capture the token at `subint_proc` entry
- swallow `trio.RunFinishedError` in that signal path for the case
where parent trio has already exited (proc teardown)
- in the teardown `finally`, off-load the sync
`driver_thread.join()` to `trio.to_thread.run_sync` (cache thread
w/ no subint tstate → safe) so we actually wait for the driver to
exit before `_interpreters.destroy()`
(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 31cbd11a5b)
Expand the comment block above the `_interpreters`
import explaining *why* we use the private C mod
over `concurrent.interpreters`: the public API only
exposes PEP 734's `'isolated'` config which breaks
`msgspec` (missing PEP 684 slot). Add reference
links to PEP 734, PEP 684, cpython sources, and
the msgspec upstream tracker (jcrist/msgspec#563).
Also,
- update error msgs in both `_spawn.py` and
`_subint.py` to say "3.13+" (matching the actual
`_interpreters` availability) instead of "3.14+".
- tweak the mod docstring to reflect py3.13+
availability via the private C module.
Review: PR #444 (copilot-pull-request-reviewer)
https://github.com/goodboy/tractor/pull/444
(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 8a8d01e076)
Replace the B.1 scaffold stub w/ a working spawn
flow driving PEP 734 sub-interpreters on dedicated
OS threads.
Deats,
- use private `_interpreters` C mod (not the public
`concurrent.interpreters` API) to get `'legacy'`
subint config — avoids PEP 684 C-ext compat
issues w/ `msgspec` and other deps missing the
`Py_mod_multiple_interpreters` slot
- bootstrap subint via code-string calling new
`_actor_child_main()` from `_child.py` (shared
entry for both CLI and subint backends)
- drive subint lifetime on an OS thread using
`trio.to_thread.run_sync(_interpreters.exec, ..)`
- full supervision lifecycle mirrors `trio_proc`:
`ipc_server.wait_for_peer()` → send `SpawnSpec`
→ yield `Portal` via `task_status.started()`
- graceful shutdown awaits the subint's inner
`trio.run()` completing; cancel path sends
`portal.cancel_actor()` then waits for thread
join before `_interpreters.destroy()`
Also,
- extract `_actor_child_main()` from `_child.py`
`__main__` block as callable entry shape bc the
subint needs it for code-string bootstrap
- add `"subint"` to the `_runtime.py` spawn-method
check so child accepts `SpawnSpec` over IPC
Prompt-IO: ai/prompt-io/claude/20260417T124437Z_5cd6df5_prompt_io.md
(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 b8f243e98d)
(MTF-only portion: kept ai/prompt-io/claude/20260417T124437Z_5cd6df5_prompt_io.md ai/prompt-io/claude/20260417T124437Z_5cd6df5_prompt_io.raw.md tractor/spawn/_subint.py)
Land the scaffolding for a future sub-interpreter (PEP 734
`concurrent.interpreters`) actor spawn backend per issue #379. The
spawn flow itself is not yet implemented; `subint_proc()` raises a
placeholder `NotImplementedError` pointing at the tracking issue —
this commit only wires up the registry, the py-version gate, and
the harness.
Deats,
- bump `pyproject.toml` `requires-python` to `>=3.12, <3.15` and
list the `3.14` classifier — the new stdlib
`concurrent.interpreters` module only ships on 3.14
- extend `SpawnMethodKey = Literal[..., 'subint']`
- `try_set_start_method('subint')` grows a new `match` arm that
feature-detects the stdlib module and raises `RuntimeError` with
a clear banner on py<3.14
- `_methods` registers the new `subint_proc()` via the same
bottom-of-module late-import pattern used for `._trio` / `._mp`
Also,
- new `tractor/spawn/_subint.py` — top-level `try: from concurrent
import interpreters` guards `_has_subints: bool`; `subint_proc()`
signature mirrors `trio_proc`/`mp_proc` so the Phase B.2 impl can
drop in without touching the registry
- re-add `import sys` to `_spawn.py` (needed for the py-version msg
in the gate-error)
- `_testing.pytest.pytest_configure` wraps `try_set_start_method()`
in a `pytest.UsageError` handler so `--spawn-backend=subint` on
py<3.14 prints a clean banner instead of a traceback
(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 d318f1f8f4)
(MTF-only portion: kept tractor/spawn/_spawn.py tractor/spawn/_subint.py)
Replace the pre-start wall-clock sleep with an indefinite
checkpoint so cancellation ordering cannot race a timer in slow CI.
Record that `Cancelled` escapes each `start_or_cancel()` await
before the enclosing nursery or cancel scope handles it.
Review: PR #479 (goodboy)
https://github.com/goodboy/tractor/pull/479
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Compare the complete canonical `Nursery.start()` protocol error
before re-surfacing ambient cancellation. Preserve child-owned
`RuntimeError` objects whose messages only resemble Trio's wording.
Cover the colliding prefix and assert the original error remains the
exception group's sole leaf.
Review: PR #479 (goodboy)
https://github.com/goodboy/tractor/pull/479
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Resolve#474 with a new `tests/trionics/test_taskc.py` (9
tests) covering the `trio.Nursery.start()` wrapper landed in
PR #464, incl. the `modden.runtime.progman.open_wks()` use
case dug out as a minimal repro.
Deats,
- the lossy `RuntimeError('child exited without calling
task_status.started()')` only fires when the child absorbs
its ambient cancel pre-`.started()` (graceful-teardown
pattern); a well-behaved child surfaces `Cancelled` direct
from `.start()` on `trio` 0.29 - verified empirically 1st.
- `test_sibling_err_not_masked_by_startup_rte`: the `modden`
case; ONLY the root-cause sibling `ValueError` escapes the
nursery with the wrapper vs. bare-`.start()`'s lossy
riding-along startup-RTE noise.
- `test_pure_oob_cancel_not_morphed_to_rte`: plain ancestor
`cs.cancel()` exits clean vs. bare's eg-wrapped RTE.
- `test_genuine_startup_rte_still_raised`: sans cancellation
the protocol-bug RTE re-raises same as bare.
- `test_childs_own_rte_never_demoted_to_cancel`: exact-msg +
`isinstance`-guard regression cover; a child's own
`RuntimeError('never got started!')`/`RuntimeError(1234)`
never demotes to a `Cancelled`.
- `test_started_value_and_args_passthru`: positional args,
`name=` and `.started()`-value forwarding.
Also,
- `use_start_or_cancel=False` params pin upstream `trio`'s
current lossy behaviour as wart-documentation: a break on
a `trio` upgrade likely means new upstream porcelain and
the wrapper deserves a re-audit.
- verified 0 flakes over 50 hammer runs + 2 impl mutations
each caught by exactly the targeted tests.
Prompt-IO: ai/prompt-io/claude/20260702T161624Z_65bf9df5_prompt_io.md
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Skip raw packet, decoded message, peer, and channel formatting when
transport logging is disabled. Keep message processing and wire
reads outside the guards so logging controls never affect IPC flow.
Also narrow the remaining pretty-struct TODO to require a
non-raising formatter with native-repr fallback.
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Remove the stale `Channel.from_addr()` design note now that its
`at_least_level()` guard avoids inactive pretty-rendering work.
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Use `Logger.isEnabledFor()` in `at_least_level()` so logger-local
and global disable controls short-circuit payload rendering.
Add `Channel.send()` coverage for effective-level, per-logger, and
global suppression while ensuring transport remains unchanged.
Caught-during: review remediation
Found-via: `/run-tests` test_log_guard_skips_payload_formatting
Review: PR #458 (goodboy)
https://github.com/goodboy/tractor/pull/458#issuecomment-5258207470
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Wrap `log.transport()` in `Channel.send()` and `log.runtime()` in
`PldRx.decode_pld()` with `log.at_least_level()` checks so that
expensive `pformat(payload)` / `repr(msg)` / `repr(pld)` calls are
skipped entirely when the respective log level is not active.
Previously the f-string arguments were eagerly evaluated before being
passed to the log method, even though `StackLevelAdapter.log()` would
then discard the message internally via its own `isEnabledFor()` check.
On high-frequency IPC paths this caused `pformat` to dominate CPU
usage (~60-70 %) as reported in #455.
This also restores the full diagnostic output (msg type, decoded
payload) that was temporarily commented out in 0373164 as a stopgap.
Resolves#455
Drop the stale sentinel experiment and fix the cancellation-path
comment. Document that cached regular `__aexit__()` failures are
always re-raised at the final consumer boundary.
Review: PR #488 (goodboy)
https://github.com/goodboy/tractor/pull/488
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Remove the unused `value` assignment after cache eviction and skip
unpacking stale resource state before raising its invariant error.
Review: PR #488 (Copilot)
https://github.com/goodboy/tractor/pull/488#pullrequestreview-4850557500
(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))
Block the final user on its cached resource's `__aexit__()` and
raise regular cleanup errors at that user's ctx boundary.
Deats,
- serialize user registration and teardown under each cache-key lock
- keep queued entrants on the same lock through resource replacement
- preserve `Cancelled`, `KeyboardInterrupt`, and `SystemExit` flow
- cover successful, failing, cancelled, and re-entry teardown paths
Prompt-IO: ai/prompt-io/opencode/20260804T030309Z_65bf9df5_prompt_io.md
(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))
Gud Boi
Bd
dependabot[bot]
root
mahmoud