After the variant-1 / variant-2 backend split, update remaining
string-match refs to the variant-1 backend so user-visible gates
+ skip-marks + comments name the working backend correctly:
- `tractor._root._DEBUG_COMPATIBLE_BACKENDS`: include
`main_thread_forkserver`, drop the stub-only `subint_forkserver`
entry.
- `tests/test_spawning.py::test_loglevel_propagated_to_subactor`:
capfd-skip flips to `main_thread_forkserver`.
- `tests/test_infected_asyncio.py::test_sigint_closes_lifetime_stack`:
xfail-condition flips to `main_thread_forkserver`.
- `tests/test_shm.py`: drop stale "broken on `main_thread_forkserver`"
reason-text since the `mp.SharedMemory(track=False)`
+ resource-tracker monkey-patch in `.ipc._mp_bs` makes the tests pass;
the skip-mark only fires on plain `subint` now.
- Comment / docstring sweep: `runtime._state`, `runtime._runtime`,
`_testing.pytest`, `_subint.py`, `pyproject.toml`,
`test_cancellation.py`, `test_registrar.py` — refs to variant-1
backend updated.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Implements the resolution described in c99d475d's
`subint_forkserver_mp_shared_memory_issue.md` (now
updated with the resolution post-mortem). Two-part
fix that side-steps `mp.resource_tracker` entirely
rather than try to make it fork-safe — turns out
that's both simpler AND more correct given tractor
already SC-manages allocation lifetimes.
Deats,
- `tractor/ipc/_mp_bs.py::disable_mantracker()`: drop the
`platform.python_version_tuple()[:-1] >= ('3', '13')` branch — patches
now run unconditionally:
* monkey-patch `mp.resource_tracker. _resource_tracker` to a no-op
`ManTracker` subclass (empty `register` / `unregister`
/ `ensure_running`).
* return `partial(SharedMemory, track=False)` for the per-allocation
opt-out.
* belt + suspenders: even if something dodges the wrapper, the
singleton can't talk to the inherited (broken) parent fd.
- `tractor/ipc/_shm.py::open_shm_list()`: drop the 3.13+ conditional
skip of the unlink-callback; install a `try_unlink()` wrapper that
swallows `FileNotFoundError` (sibling-already-cleaned race in
shared-key setups). Without `mp.resource_tracker` doing it for us, we
own the unlink — `actor. lifetime_stack` is the right place since
tractor already controls actor lifecycle.
- `tests/test_shm.py`: uncomment-out `subint_forkserver` from the
module-level skip- list (tests pass now). Inline comment cross-refs
the two `_mp_bs` / `_shm` workarounds.
- `ai/conc-anal/subint_forkserver_mp_shared_memory_ issue.md`: heavy
rewrite — flips status from "open / unresolvable in tractor" to
"resolved, kept as decision record". Adds Resolution section, "Why
this is the right call" rationale (mp tracker is widely criticized;
tractor already owns lifecycle), trade-offs (crash-leaked segments,
lost mp leak warning), verification (7 passed under both
`subint_forkserver` and `trio` backends), and upstream issue links
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
New `ai/conc-anal/` doc: `mp.SharedMemory` is
fork-without-exec unsafe — child inherits parent's
`resource_tracker` fd → EBADF on first shm op;
leaked `/shm_list` cascades `FileExistsError`
across parametrize variants. Canonical CPython
issue class, NOT a tractor bug. Includes two
longer-term mitigation paths (reset inherited
tracker fd vs migrate off `mp.shared_memory`).
Also, update `tests/test_shm.py`:
- comment out `subint_forkserver` from skip list
- rewrite reason with precise failure-mode
descriptions + link to the analysis doc
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Lands the capture-pipe workaround from the prior cluster of diagnosis
commits: switch pytest's `--capture` mode from the default `fd`
(redirects fd 1,2 to temp files, which fork children inherit and can
deadlock writing into) to `sys` (only `sys.stdout` / `sys.stderr` — fd
1,2 left alone).
Trade-off documented inline in `pyproject.toml`:
- LOST: per-test attribution of raw-fd output (C-ext writes,
`os.write(2, ...)`, subproc stdout). Still goes to terminal / CI
capture, just not per-test-scoped in the failure report.
- KEPT: `print()` + `logging` capture per-test (tractor's logger uses
`sys.stderr`).
- KEPT: `pytest -s` debugging behavior.
This allows us to re-enable `test_nested_multierrors` without
skip-marking + clears the class of pytest-capture-induced hangs for any
future fork-based backend tests.
Deats,
- `pyproject.toml`: `'--capture=sys'` added to `addopts` w/ ~20 lines of
rationale comment cross-ref'ing the post-mortem doc
- `test_cancellation`: drop `skipon_spawn_backend('subint_forkserver')`
from `test_nested_ multierrors` — no longer needed.
* file-level `pytestmark` covers any residual.
- `tests/spawn/test_subint_forkserver.py`: orphan-SIGINT test's xfail
mark loosened from `strict=True` to `strict=False` + reason rewritten.
* it passes in isolation but is session-env-pollution sensitive
(leftover subactor PIDs competing for ports / inheriting harness
FDs).
* tolerate both outcomes until suite isolation improves.
- `test_shm`: extend the existing
`skipon_spawn_backend('subint', ...)` to also skip
`'subint_forkserver'`.
* Different root cause from the cancel-cascade class:
`multiprocessing.SharedMemory`'s `resource_tracker` + internals
assume fresh- process state, don't survive fork-without-exec cleanly
- `tests/discovery/test_registrar.py`: bump timeout 3→7s on one test
(unrelated to forkserver; just a flaky-under-load bump).
- `tractor.spawn._subint_forkserver`: inline comment-only future-work
marker right before `_actor_child_main()` describing the planned
conditional stdout/stderr-to-`/dev/null` redirect for cases where
`--capture=sys` isn't enough (no code change — the redirect logic
itself is deferred).
EXTRA NOTEs
-----------
The `--capture=sys` approach is the minimum- invasive fix: just a pytest
ini change, no runtime code change, works for all fork-based backends,
trade-offs well-understood (terminal-level capture still happens, just
not pytest's per-test attribution of raw-fd output).
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Adopt the `@pytest.mark.skipon_spawn_backend('subint',
reason=...)` marker (a617b521) across the suites
reproducing the `subint` GIL-contention / starvation
hang classes doc'd in `ai/conc-anal/subint_*_issue.md`.
Deats,
- Module-level `pytestmark` on full-file-hanging suites:
- `tests/test_cancellation.py`
- `tests/test_inter_peer_cancellation.py`
- `tests/test_pubsub.py`
- `tests/test_shm.py`
- Per-test decorator where only one test in the file
hangs:
- `tests/discovery/test_registrar.py
::test_stale_entry_is_deleted` — replaces the
inline `if start_method == 'subint': pytest.skip`
branch with a declarative skip.
- `tests/test_subint_cancellation.py
::test_subint_non_checkpointing_child`.
- A few per-test decorators are left commented-in-
place as breadcrumbs for later finer-grained unskips.
Also, some nearby tidying in the affected files:
- Annotate loose fixture / test params
(`pytest.FixtureRequest`, `str`, `tuple`, `bool`) in
`tests/conftest.py`, `tests/devx/conftest.py`, and
`tests/test_cancellation.py`.
- Normalize `"""..."""` → `'''...'''` docstrings per
repo convention on a few touched tests.
- Add `timeout=6` / `timeout=10` to
`@tractor_test(...)` on `test_cancel_infinite_streamer`
and `test_some_cancels_all`.
- Drop redundant `spawn_backend` param from
`test_cancel_via_SIGINT`; use `start_method` in the
`'mp' in ...` check instead.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
EventFD class now expects the fd to already be init with open_eventfd
RingBuff Sender and Receiver fully manage SharedMemory and EventFD lifecycles, no aditional ctx mngrs needed
Separate ring buf tests into its own test bed
Add parametrization to test and cancellation
Add docstrings
Add simple testing data gen module .samples
Demonstrates fixed size frame-oriented reads by the child where the
parent only transmits a "read" stream msg on "frame fill events" such
that the child incrementally reads the shm list data (much like in
a real-time-buffered streaming system).
Gud Boi
Guillermo Rodriguez
Tyler Goodlet