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)
`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)
Inside a new new `tractor.spawn._reap` submod which kicks off providing
post-mortem subactor cleanup primitives, parent-side; consider it the
"sibling" of `tractor._testing._reap` which is the test-harness-oriented
brother mod.
Today: `unlink_uds_bind_addrs()` provides a starter bug-fix for #454
where `hard_kill()`'s `SIGKILL` bypasses the subactor's
`_serve_ipc_eps`-`finally:` `os.unlink(addr.sockpath)`, leaking
`${XDG_RUNTIME_DIR}/tractor/<name>@<pid>.sock` files..
This adds 2 cleanup paths:
- explicit `bind_addrs` (when set at spawn time),
OR
- convention-based reconstruction from `subactor.aid.name + proc.pid`
for the random-self-assign case.
`.spawn.hard_kill()` now invokes the cleanup unconditionally
post-`SIGKILL`; graceful-exit case is a no-op via `FileNotFoundError`
skip.
Future work — authoritative tracking via a per-process
UDS bind-addr registry — documented in module docstring,
deferred to a follow-up PR.
Co-fix: `tractor/spawn/_trio.py::new_proc` already passes
`bind_addrs` + `subactor` to `hard_kill` via prior work
on this branch.
(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 e9712dcaeb)
During the Phase A extraction of `trio_proc()` out of
`spawn._spawn` into its own submod, the
`debug.maybe_wait_for_debugger(child_in_debug=...)` call site in
the hard-reap `finally` got refactored from the original
`_runtime_vars.get('_debug_mode', ...)` (the fn parameter — the
dict that was constructed by the *parent* for the *child*'s
`SpawnSpec`) to `get_runtime_vars().get(...)` (a global getter that
returns the *parent's* live `_state`). Those are semantically
different — the first asks "is the child we just spawned in debug
mode?", the second asks "are *we* in debug mode?". Under
mixed-debug-mode trees the swap can incorrectly skip (or
unnecessarily delay) the debugger-lock wait during teardown.
Revert to the fn-parameter lookup and add an inline `NOTE` comment
calling out the distinction so it's harder to regress again.
Deats,
- `spawn/_trio.py`: `child_in_debug=get_runtime_vars().get(...)` →
`child_in_debug=_runtime_vars.get(...)` at the
`debug.maybe_wait_for_debugger(...)` call in the hard-reap block;
add 4-line `NOTE` explaining the parent-vs-child distinction.
- `spawn/__init__.py`: drop trailing whitespace after the
`'mp_forkserver'` docstring bullet.
- `ai/prompt-io/prompts/subints_spawner.md`: drop duplicated `with`
in `"as with with subprocs"` prose (copilot grammar catch).
Review: PR #444 (Copilot)
https://github.com/goodboy/tractor/pull/444#pullrequestreview-4165928469
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Drop unused `TYPE_CHECKING` imports (`Channel`,
`_server`), remove commented-out `import os` in
`_entry.py`, and use `get_runtime_vars()` accessor
instead of bare `_runtime_vars` in `_trio.py`.
Also,
- freshen `__init__.py` layout docstring for the
new per-backend submod structure
- update `_spawn.py` + `_trio.py` module docstrings
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Split the monolithic `spawn._spawn` into a slim
"core" + per-backend submodules so a future
`._subint` backend (per issue #379) can drop in
without piling more onto `_spawn.py`.
`._spawn` retains the cross-backend supervisor
machinery: `SpawnMethodKey`, `_methods` registry,
`_spawn_method`/`_ctx` state, `try_set_start_method()`,
the `new_proc()` dispatcher, and the shared helpers
`exhaust_portal()`, `cancel_on_completion()`,
`hard_kill()`, `soft_kill()`, `proc_waiter()`.
Deats,
- mv `trio_proc()` → new `spawn._trio`
- mv `mp_proc()` → new `spawn._mp`, reads `_ctx` and
`_spawn_method` via `from . import _spawn` for
late binding bc both get mutated by
`try_set_start_method()`
- `_methods` wires up the new submods via late
bottom-of-module imports to side-step circular
dep (both backend mods pull shared helpers from
`._spawn`)
- prune now-unused imports from `_spawn.py` — `sys`,
`is_root_process`, `current_actor`,
`is_main_process`, `_mp_main`, `ActorFailure`,
`pretty_struct`, `_pformat`
Also,
- `_testing.pytest.pytest_generate_tests()` now
drives the valid-backend set from
`typing.get_args(SpawnMethodKey)` so adding a
new backend (e.g. `'subint'`) doesn't require
touching the harness
- refresh `spawn/__init__.py` docstring for the
new layout
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
- "spawing" → "spawning", close unbalanced
backtick on `` `start_method='trio'` ``
- "uneeded" → "unneeded", "deats" → "details"
- Remove double `d` annotation; filter
`get_preparation_data()` result into only
`ParentMainData` keys before returning
- Use `pop('authkey', None)` for safety
Review: PR #1 (Copilot)
https://github.com/mahmoudhas/tractor/pull/1#pullrequestreview-4091096072
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Drop hand-copied `_fixup_main_from_name()` and `_fixup_main_from_path()`
in favor of direct re-exports from `multiprocessing.spawn`. Simplify
`_mp_figure_out_main()` to call stdlib's `get_preparation_data()`
instead of reimplementing `__main__` module inspection inline.
Also,
- drop `ORIGINAL_DIR` global and `os`, `sys`, `platform`, `types`,
`runpy` imports.
- pop `authkey` from prep data (unserializable and unneeded by our spawn
path).
- update mod docstring to reflect delegation.
Review: PR #438 (Copilot)
https://github.com/goodboy/tractor/pull/438
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Clean up mutable defaults, give parent-main bootstrap data a named type, and add direct start_actor coverage so the opt-out change is clearer to review.
Use `inherit_parent_main` across the actor APIs and helper to better describe the behavior, and restore the reviewer note at child bootstrap where the inherited `__main__` data is copied from `SpawnSpec`.
Keep actor-owned parent-main capture and let `_mp_figure_out_main()` decide whether to return `__main__` bootstrap data, avoiding the extra SpawnSpec plumbing while preserving the per-actor flag.
Keep trio child bootstrap data in the spawn handshake instead of stashing it on Actor state so the replay opt-out stays explicit and avoids stale-looking runtime fields.
Restructure the flat `tractor/` top-level private mods
into (more nested) subpackages:
- `runtime/`: `_runtime`, `_portal`, `_rpc`, `_state`,
`_supervise`
- `spawn/`: `_spawn`, `_entry`, `_forkserver_override`,
`_mp_fixup_main`
- `discovery/`: `_addr`, `_discovery`, `_multiaddr`
Each subpkg `__init__.py` is kept lazy (no eager
imports) to avoid circular import issues.
Also,
- update all intra-pkg imports across ~35 mods to use
the new subpkg paths (e.g. `from .runtime._state`
instead of `from ._state`)
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi
mahmoud