Harden `test_cancellation` for fork-spawner backends
Deats,
- `pytestmark`: enrich `skipon_spawn_backend('subint')` reason with
conc-anal doc refs + GH#379 link, add `reap_subactors_per_test`,
`track_orphaned_uds_per_test`,
`detect_runaway_subactors_per_test` fixtures
- `test_nested_multierrors`: parametrize over `depth` `{1, 3}`, add
MTF `xfail(strict=False)` with detailed race-window comment
explaining the BEG shape mismatch, wrap body in
`fail_after_w_trace` with per-backend timeout budget, bump
`@tractor_test(timeout=10)`, drop old multiprocessing depth
special-casing
- `test_multierror_fast_nursery`: wrap in
`fail_after_w_trace(30.0)`, accept `TooSlowError` in
`pytest.raises`, surface explicit `pytest.fail` on hang
- `test_cancel_while_childs_child_in_sync_sleep`: swap
`spawn_backend` param for `is_forking_spawner`, widen
`fail_after` delay for fork-based spawners
- `test_remote_error`, `test_multierror`,
`test_cancel_infinite_streamer`, `test_some_cancels_all`: add
`set_fork_aware_capture` fixture param
- Drop commented-out per-test `skipon_spawn_backend` blocks (now
covered by module-level `pytestmark`)
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
subint_forkserver_backend
parent
5372fd178a
commit
32955db02e
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@ -7,6 +7,7 @@ import signal
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import platform
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import time
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from itertools import repeat
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from typing import Type
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import pytest
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import trio
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@ -14,6 +15,7 @@ import tractor
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from tractor._testing import (
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tractor_test,
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)
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from tractor._testing.trace import FailAfterWTraceFactory
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from .conftest import no_windows
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@ -21,14 +23,44 @@ _non_linux: bool = platform.system() != 'Linux'
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_friggin_windows: bool = platform.system() == 'Windows'
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pytestmark = pytest.mark.skipon_spawn_backend(
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'subint',
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reason=(
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'XXX SUBINT HANGING TEST XXX\n'
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'See oustanding issue(s)\n'
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# TODO, put issue link!
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)
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)
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pytestmark = [
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# Multi-actor cancel cascades under
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# `--spawn-backend=subint` trip the abandoned-subint
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# GIL-hostage class — a stuck subint can starve the
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# parent's trio loop and block cancel-delivery.
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# Apply the skip module-wide rather than per-test
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# since every test here exercises the same cascade.
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pytest.mark.skipon_spawn_backend(
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'subint',
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reason=(
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'XXX SUBINT GIL-CONTENTION HANGING TEST XXX\n'
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'Cancel cascades under '
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'`--spawn-backend=subint` trip the abandoned-subint '
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'GIL-hostage class — see\n'
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' - `ai/conc-anal/subint_sigint_starvation_issue.md` '
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'(GIL-hostage, SIGINT-unresponsive)\n'
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' - `ai/conc-anal/subint_cancel_delivery_hang_issue.md` '
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'(sibling: parent parks on dead chan)\n'
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' - https://github.com/goodboy/tractor/issues/379 '
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'(subint umbrella)\n'
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)
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),
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pytest.mark.usefixtures(
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'reap_subactors_per_test',
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# NOTE, cancellation tests stress the SIGKILL
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# `hard_kill` path which leaks UDS sock-files when
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# the subactor's IPC server `finally:` cleanup
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# doesn't run. Track per-test for blame attribution.
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'track_orphaned_uds_per_test',
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# NOTE, cancel-cascade timing races (see
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# `test_nested_multierrors`) can also leave a
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# subactor spinning at 100% CPU when its cancel
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# signal got swallowed mid-handshake. Catches the
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# runaway-loop class that doesn't leak UDS socks
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# but burns the box.
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'detect_runaway_subactors_per_test',
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),
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]
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async def assert_err(delay=0):
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@ -55,7 +87,11 @@ async def do_nuthin():
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],
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ids=['no_args', 'unexpected_args'],
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)
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def test_remote_error(reg_addr, args_err):
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def test_remote_error(
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reg_addr: tuple,
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args_err: tuple[dict, Type[Exception]],
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set_fork_aware_capture,
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):
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'''
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Verify an error raised in a subactor that is propagated
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to the parent nursery, contains the underlying boxed builtin
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@ -120,17 +156,10 @@ def test_remote_error(reg_addr, args_err):
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assert exc.boxed_type == errtype
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# @pytest.mark.skipon_spawn_backend(
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# 'subint',
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# reason=(
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# 'XXX SUBINT HANGING TEST XXX\n'
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# 'See oustanding issue(s)\n'
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# # TODO, put issue link!
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# )
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# )
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def test_multierror(
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reg_addr: tuple[str, int],
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start_method: str,
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start_method: str, # parametrized
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set_fork_aware_capture, #: Callable,
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):
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'''
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Verify we raise a ``BaseExceptionGroup`` out of a nursery where
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@ -175,6 +204,8 @@ def test_multierror_fast_nursery(
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start_method: str,
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num_subactors: int,
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delay: float,
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set_fork_aware_capture,
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fail_after_w_trace: FailAfterWTraceFactory,
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):
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'''
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Verify we raise a ``BaseExceptionGroup`` out of a nursery where
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@ -183,21 +214,43 @@ def test_multierror_fast_nursery(
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'''
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async def main():
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async with tractor.open_nursery(
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registry_addrs=[reg_addr],
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) as nursery:
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# budget = 2× natural trio-backend cascade time for
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# 25 errorer subactors (~14s observed). on-timeout
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# diag snapshot → if the cancel cascade hangs
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# (observed under MTF backend with N>=14 errorer
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# subactors) we get a fresh ptree/wchan/py-spy dump
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# on disk INSTEAD of an opaque pytest timeout-kill.
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# See `tractor/_testing/trace.py` for the helper.
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async with fail_after_w_trace(30.0):
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async with tractor.open_nursery(
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registry_addrs=[reg_addr],
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) as nursery:
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for i in range(num_subactors):
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await nursery.run_in_actor(
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assert_err,
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name=f'errorer{i}',
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delay=delay
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)
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for i in range(num_subactors):
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await nursery.run_in_actor(
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assert_err,
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name=f'errorer{i}',
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delay=delay
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)
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# with pytest.raises(trio.MultiError) as exc_info:
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with pytest.raises(BaseExceptionGroup) as exc_info:
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# NOTE, `trio.TooSlowError` from `fail_after_w_trace`
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# bubbles UN-wrapped if `open_nursery.__aexit__` never
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# gets re-entered; wrapped inside a `BaseExceptionGroup`
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# if it did. Accept both shapes so the matcher itself
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# doesn't lie about *what* failed.
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with pytest.raises(
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(BaseExceptionGroup, trio.TooSlowError),
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) as exc_info:
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trio.run(main)
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if isinstance(exc_info.value, trio.TooSlowError):
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pytest.fail(
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f'cancel cascade hung past 12s '
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f'(num_subactors={num_subactors}, delay={delay}); '
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f'see stderr for `fail_after_w_trace` snapshot path'
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)
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assert exc_info.type == ExceptionGroup
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err = exc_info.value
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exceptions = err.exceptions
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@ -277,6 +330,7 @@ async def stream_forever():
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async def test_cancel_infinite_streamer(
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reg_addr: tuple,
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start_method: str,
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set_fork_aware_capture,
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):
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# stream for at most 1 seconds
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with (
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@ -300,14 +354,6 @@ async def test_cancel_infinite_streamer(
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assert n.cancelled
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# @pytest.mark.skipon_spawn_backend(
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# 'subint',
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# reason=(
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# 'XXX SUBINT HANGING TEST XXX\n'
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# 'See oustanding issue(s)\n'
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# # TODO, put issue link!
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# )
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# )
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@pytest.mark.parametrize(
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'num_actors_and_errs',
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[
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@ -345,6 +391,7 @@ async def test_some_cancels_all(
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reg_addr: tuple,
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start_method: str,
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loglevel: str,
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set_fork_aware_capture, #: Callable,
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):
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'''
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Verify a subset of failed subactors causes all others in
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@ -462,32 +509,119 @@ async def spawn_and_error(
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# 10,
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# method='thread',
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# )
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@tractor_test
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@pytest.mark.parametrize(
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'depth',
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[1, 3],
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ids='depth={}'.format,
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)
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@tractor_test(
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# bumped from the 30s default to cover fork-based
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# cancel-cascade flakes; 2 spawners × 2 errorers × depth 1+
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# cascade through 6 portal-wait_for_result paths each
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# paying `terminate_after=1.6s` + UDS sock-unlink under
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# MTF/UDS contention can easily blow past 30s.
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# Trio backend is fast and won't notice the extra budget.
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# See `ai/conc-anal/cancel_cascade_too_slow_under_main_thread_forkserver_issue.md`.
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timeout=10,
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)
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async def test_nested_multierrors(
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reg_addr: tuple,
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loglevel: str,
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start_method: str,
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set_fork_aware_capture,
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fail_after_w_trace: FailAfterWTraceFactory,
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request: pytest.FixtureRequest,
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depth: int,
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):
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'''
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Test that failed actor sets are wrapped in `BaseExceptionGroup`s. This
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test goes only 2 nurseries deep but we should eventually have tests
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for arbitrary n-depth actor trees.
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Test that failed actor sets are wrapped in `BaseExceptionGroup`s.
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Parametrized over recursion `depth ∈ {1, 3}`:
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- `depth=1`: shallow tree (2 spawners × 2 errorers, 2
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levels). Cascade completes well within budget on ALL
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backends including MTF — regression-safety green case.
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- `depth=3`: deep tree (2 spawners × recursive depth-3
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spawn-and-error). On `main_thread_forkserver` this
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trips the cancel-cascade shape-mismatch bug class
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(see `ai/conc-anal/cancel_cascade_too_slow_under_main_thread_forkserver_issue.md`)
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— xfailed below.
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'''
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if start_method == 'trio':
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depth = 3
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subactor_breadth = 2
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else:
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# XXX: multiprocessing can't seem to handle any more then 2 depth
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# process trees for whatever reason.
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# Any more process levels then this and we see bugs that cause
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# hangs and broken pipes all over the place...
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if start_method == 'forkserver':
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pytest.skip("Forksever sux hard at nested spawning...")
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depth = 1 # means an additional actor tree of spawning (2 levels deep)
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subactor_breadth = 2
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# XXX: `multiprocessing.forkserver` can't handle nested
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# spawning at any depth — hangs / broken-pipes. Pre-existing
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# backend limitation, NOT depth-specific.
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if start_method == 'forkserver':
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pytest.skip("Forksever sux hard at nested spawning...")
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with trio.fail_after(120):
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subactor_breadth = 2
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# MTF backend trips a probabilistic timing race in the
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# cancel-cascade — NOT depth-gated; depth amplifies the
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# variance so depth=3 misses nearly every run while
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# depth=1 misses occasionally. Both get the xfail mark
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# (with `strict=False`) since the bug class can fire at
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# either depth.
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#
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# The scenario in detail:
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#
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# T=0 spawn spawner_0 + spawner_1 in parallel
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# T=t1 spawner_0's child errors →
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# RemoteActorError reaches root nursery
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# T=t1+ε root nursery starts cancelling
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# spawner_1's portal-wait
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# T=t2 spawner_1's child errors → tries to send
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# RemoteActorError back
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#
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# if t2 < t1+ε: BEG = [RAE, RAE] ← clean (xpass)
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# if t2 > t1+ε: BEG = [RAE, Cancelled] ← race tripped (xfail)
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#
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# i.e. the assertion below (`isinstance(_, RemoteActorError)`)
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# fails iff cancel-delivery beats the other tree's natural
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# error-propagation. Depth amplifies `t2-t1` variance
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# (longer per-tree paths = more skew); under MTF the
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# fork-spawn jitter + UDS-contention widens both `t1` and
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# `t2` further.
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#
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# With `strict=False` the clean-cascade cases (most
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# depth=1 runs, rare depth=3 runs) report as `xpassed`
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# while the race-tripped cases report as `xfailed` —
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# neither flakes `--lf`. When MTF cancel-cascade
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# eventually speeds up enough to close the race even at
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# depth=3, BOTH variants will reliably `xpass` and
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# pytest will yell — our signal to drop the marker. See
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# `ai/conc-anal/cancel_cascade_too_slow_under_main_thread_forkserver_issue.md`.
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if start_method == 'main_thread_forkserver':
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request.node.add_marker(
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pytest.mark.xfail(
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strict=False,
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reason=(
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f'MTF cancel-cascade shape-mismatch at '
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f'depth={depth} (Cancelled races '
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f'RemoteActorError in BEG); see conc-anal/'
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'cancel_cascade_too_slow_under_main_thread_forkserver_issue.md'
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),
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)
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)
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# 6s budget: in the non-hang case (and on the trio
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# backend) the whole spawn + cancel-cascade should
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# complete in well under that. On the borderline hang
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# case the `fail_after_w_trace` fires `TooSlowError`
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# AND captures a ptree/wchan/py-spy snapshot to
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# `$XDG_CACHE_HOME/tractor/hung-dumps/` for offline
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# inspection. See
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# `ai/conc-anal/cancel_cascade_too_slow_under_main_thread_forkserver_issue.md`.
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match (start_method, depth):
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case ('trio', _):
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timeout = 6
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case ('main_thread_forkserver', 1):
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timeout = 16
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case ('main_thread_forkserver', 3):
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timeout = 30
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async with fail_after_w_trace(timeout):
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try:
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async with tractor.open_nursery() as nursery:
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for i in range(subactor_breadth):
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@ -658,14 +792,6 @@ async def spawn_sub_with_sync_blocking_task():
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print('exiting first subactor layer..\n')
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# @pytest.mark.skipon_spawn_backend(
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# 'subint',
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# reason=(
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# 'XXX SUBINT HANGING TEST XXX\n'
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# 'See oustanding issue(s)\n'
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# # TODO, put issue link!
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# )
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# )
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@pytest.mark.parametrize(
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'man_cancel_outer',
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[
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|
|
@ -685,7 +811,7 @@ async def spawn_sub_with_sync_blocking_task():
|
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def test_cancel_while_childs_child_in_sync_sleep(
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loglevel: str,
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start_method: str,
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spawn_backend: str,
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is_forking_spawner: bool,
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debug_mode: bool,
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reg_addr: tuple,
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man_cancel_outer: bool,
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|
|
@ -701,7 +827,10 @@ def test_cancel_while_childs_child_in_sync_sleep(
|
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|
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'''
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if start_method == 'forkserver':
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pytest.skip("Forksever sux hard at resuming from sync sleep...")
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pytest.skip(
|
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"`multiprocessing`'s forkserver sux hard at "
|
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"resuming from sync sleep..."
|
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)
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|
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async def main():
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#
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|
|
@ -744,7 +873,11 @@ def test_cancel_while_childs_child_in_sync_sleep(
|
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# delay = 2 # is AssertionError in eg AND no TooSlowError !?
|
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# is AssertionError in eg AND no _cs cancellation.
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delay = (
|
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6 if _non_linux
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6 if (
|
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_non_linux
|
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or
|
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is_forking_spawner
|
||||
)
|
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else 4
|
||||
)
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue