Merge pull request #475 from goodboy/windows_support_round2

Restore Windows support (optional UDS + `SIGUSR1`)

.github/workflows/ci.yml

@@ -91,6 +91,10 @@ jobs:
     name: '${{ matrix.os }} Python${{ matrix.python-version }} spawn_backend=${{ matrix.spawn_backend }} tpt_proto=${{ matrix.tpt_proto }}'
     timeout-minutes: 16
     runs-on: ${{ matrix.os }}
+    # Windows support is nascent: its full test suite remains
+    # informational, while setup and the `import tractor` smoke below
+    # are hard signals. Promote the test step to required once the
+    # suite is green.
 
     strategy:
       fail-fast: false
@@ -98,6 +102,7 @@ jobs:
         os: [
           ubuntu-latest,
           macos-latest,
+          windows-latest,
         ]
         python-version: [
           '3.13',
@@ -118,6 +123,11 @@ jobs:
           'tcp',
           'uds',
         ]
+        exclude:
+          # UDS is POSIX-only; Windows has no `AF_UNIX` so the
+          # backend is intentionally unavailable there.
+          - os: windows-latest
+            tpt_proto: 'uds'
 
     steps:
       - uses: actions/checkout@v4
@@ -145,7 +155,14 @@ jobs:
       - name: List deps tree
         run: uv tree
 
+      # hard signal for the Windows import-safety fix: `import
+      # tractor` must succeed everywhere, and `HAS_UDS` reflects
+      # platform capability (False on Windows, True on POSIX).
+      - name: 'Smoke: import tractor'
+        run: uv run python -c "import sys; import tractor; from tractor.ipc._uds import HAS_UDS; assert sys.platform != 'win32' or not HAS_UDS; print('import tractor OK | HAS_UDS=', HAS_UDS)"
+
       - name: Run tests
+        continue-on-error: ${{ matrix.os == 'windows-latest' }}
         run: >
           uv run
           pytest

ai/prompt-io/opencode/20260817T231825Z_359fe75c_prompt_io.md

@@ -0,0 +1,39 @@
+---
+model: openai/gpt-5.6-sol
+service: opencode
+session: pr475-review-fixes-20260817
+timestamp: 2026-08-17T23:18:25Z
+git_ref: 359fe75c
+scope: code
+substantive: true
+raw_file: 20260817T231825Z_359fe75c_prompt_io.raw.md
+---
+
+## Prompt
+
+Continue the `/code-review-changes` pass for PR #475 in its isolated
+worktree. Address the seven accepted manual-review findings in
+`tractor/ipc/_types.py` and `tractor/ipc/_uds.py`, preserve the existing
+Windows capability behavior, verify the result, and prepare the work for
+human-controlled commit and review-reply steps. Do not publish replies,
+stage, commit, or push without the required explicit authorization.
+
+## Response summary
+
+Restored project quote, docstring, multiline-expression, and
+`match/case` conventions while retaining the Windows-safe UDS guard.
+Removed unnecessary structural and comment churn, then verified the
+focused transport, discovery, and lazy-import paths plus the missing
+`AF_UNIX` behavior.
+
+## Files changed
+
+- `tractor/ipc/_types.py` - restore project style and guarded
+  socket-family dispatch.
+- `tractor/ipc/_uds.py` - format the UDS capability gate
+  consistently.
+
+## Human edits
+
+None - the generated patch remains uncommitted and awaits human
+review.

ai/prompt-io/opencode/20260817T231825Z_359fe75c_prompt_io.raw.md

@@ -0,0 +1,45 @@
+---
+model: openai/gpt-5.6-sol
+service: opencode
+timestamp: 2026-08-17T23:18:25Z
+git_ref: 359fe75c
+diff_cmd: git diff HEAD~1..HEAD
+---
+
+Applied the seven accepted manual-review fixes for PR #475 while
+preserving the Windows transport capability behavior.
+
+> `git diff HEAD~1..HEAD -- tractor/ipc/_types.py`
+
+The generated changes restore the project's single-quote docstring and
+string conventions, remove the unnecessary helper divider, simplify the
+transport-registry comments, and restore `match/case` socket-family
+dispatch. The UDS case retains a `HAS_UDS` guard that short-circuits
+before `socket.AF_UNIX` is evaluated on unsupported hosts. Nearby error
+messages are wrapped without changing their content.
+
+> `git diff HEAD~1..HEAD -- tractor/ipc/_uds.py`
+
+The generated change reformats the `HAS_UDS` conjunction according to
+the project's multiline boolean-expression convention and simplifies
+the adjacent capability comment.
+
+Verification:
+
+`/home/goodboy/repos/tractor/py313/bin/pytest -q tests/test_lazy_imports.py tests/discovery tests/ipc/test_server.py`
+
+Result: `66 passed, 2 xpassed in 60.62s`.
+
+`ruff check --no-cache --output-format=json tractor/ipc/_types.py tractor/ipc/_uds.py`
+
+Result: no findings.
+
+`git diff --check`
+
+Result: no whitespace errors.
+
+An explicit missing-`AF_UNIX` probe set `HAS_UDS = False`, removed the
+socket constant, and exercised an unsupported socket family. It raised
+the expected `NotImplementedError` instead of `AttributeError`.
+
+No review replies, commits, or pushes were published.

tests/test_infected_asyncio.py

@@ -20,6 +20,18 @@ from typing import (
 import pytest
 import trio
 import tractor
+
+# `infect_asyncio` mode is unsupported on Windows (asyncio's
+# `ProactorEventLoop` is incompatible with our `trio` guest-mode
+# interop and currently hangs/crashes the run). Skip the module on
+# Windows so the CI leg completes + reports the rest of the suite.
+import platform
+if platform.system() == 'Windows':
+    pytest.skip(
+        'infect_asyncio mode is unsupported on Windows',
+        allow_module_level=True,
+    )
+
 from tractor import (
     current_actor,
     Actor,

tests/test_ringbuf.py

@@ -1,10 +1,22 @@
 import time
+import platform
 
 import trio
 import pytest
 
 import tractor
 
+# `tractor.ipc._ringbuf` is built on linux `eventfd(2)`; importing
+# it pulls in `tractor.ipc._linux` whose module-level
+# `ffi.dlopen(None)` raises on non-linux. Skip the whole module at
+# COLLECTION before that crashing import runs (a `pytestmark` skip
+# is too late — markers apply only after the import succeeds).
+if platform.system() != 'Linux':
+    pytest.skip(
+        'ringbuf (eventfd) IPC is linux-only',
+        allow_module_level=True,
+    )
+
 # XXX `cffi` dun build on py3.14 yet..
 pytest.importorskip("cffi")
 

tests/test_root_infect_asyncio.py

@@ -9,6 +9,17 @@ from functools import partial
 import pytest
 import trio
 import tractor
+
+# `infect_asyncio` mode is unsupported on Windows (see
+# `test_infected_asyncio`); skip at COLLECTION before the
+# asyncio-interop imports below so the CI leg completes.
+import platform
+if platform.system() == 'Windows':
+    pytest.skip(
+        'infect_asyncio mode is unsupported on Windows',
+        allow_module_level=True,
+    )
+
 from tractor import (
     to_asyncio,
 )

tests/test_runtime.py

@@ -73,6 +73,11 @@ async def test_lifetime_stack_wipes_tmpfile(
         1.6 if error_in_child
         else 1
     )
+    # scale for slow/noisy CI (esp. macOS) so the child error
+    # propagates before the deadline; otherwise `move_on_after`
+    # cancels first and flips the `error_in_child=True` assert.
+    from .conftest import cpu_perf_headroom
+    timeout *= cpu_perf_headroom()
     try:
         with trio.move_on_after(timeout) as cs:
             async with tractor.open_nursery(

tests/test_shm.py

@@ -120,6 +120,13 @@ async def child_read_shm_list(
                 print(f'(child): reading frame: {frame}')
 
 
+@pytest.mark.skipif(
+    platform.system() == 'Windows',
+    reason=(
+        'parent/child shm IPC deadlocks on Windows '
+        '(frame-size dependent hang); nascent — see #404'
+    ),
+)
 @pytest.mark.parametrize(
     'use_str',
     [False, True],

tractor/devx/_stackscope.py

@@ -31,12 +31,21 @@ from threading import (
     RLock,
 )
 import multiprocessing as mp
+
+import platform
+
 from signal import (
     signal,
     getsignal,
-    SIGUSR1,
     SIGINT,
 )
+
+
+if platform.system() != "Windows":
+    from signal import SIGUSR1
+else:
+    SIGUSR1 = None
+
 # import traceback
 from types import ModuleType
 from typing import (
@@ -347,8 +356,8 @@ def dump_tree_on_sig(
 
 
 def enable_stack_on_sig(
-    sig: int = SIGUSR1,
+    sig: int|None = SIGUSR1,
-) -> ModuleType:
+) -> ModuleType|None:
     '''
     Enable `stackscope` tracing on reception of a signal; by
     default this is SIGUSR1.
@@ -367,6 +376,16 @@ def enable_stack_on_sig(
     >> pkill --signal SIGUSR1 -f <part-of-cmd: str>
 
     '''
+    # no `SIGUSR1` on this platform (e.g. Windows) -> nothing to
+    # wire up; degrade gracefully instead of crashing callers that
+    # only guard against a missing `stackscope` (`ImportError`).
+    if sig is None:
+        log.warning(
+            'No `SIGUSR1` on this platform;\n'
+            'skipping `stackscope` trace-on-signal setup!\n'
+        )
+        return None
+
     try:
         # NOTE, `stackscope._glue` does intentional async-gen type
         # introspection at import-time which trips

tractor/discovery/_addr.py

@@ -32,7 +32,10 @@ from ..runtime._state import (
     _def_tpt_proto,
 )
 from ..ipc._tcp import TCPAddress
-from ..ipc._uds import UDSAddress
+from ..ipc._uds import (
+    UDSAddress,
+    HAS_UDS,
+)
 
 if TYPE_CHECKING:
     # ONLY type-annots, the eager import costs ~4.5ms
@@ -43,7 +46,6 @@ else:
 
 log = get_logger()
 
-
 # TODO, maybe breakout the netns key to a struct?
 # class NetNs(Struct)[str, int]:
 #     ...
@@ -174,25 +176,36 @@ class Address(Protocol):
         ...
 
 
+# the address types available on this host: TCP always, UDS only
+# where usable (`HAS_UDS`). Both registries derive from this single
+# list via each type's `proto_key`.
+_address_protos: list[Type[Address]] = [TCPAddress]
+if HAS_UDS:
+    _address_protos.append(UDSAddress)
+
 _address_types: dict[str, Type[Address]] = {
-    'tcp': TCPAddress,
+    cls.proto_key: cls
-    'uds': UDSAddress
+    for cls in _address_protos
 }
 
 
 # TODO! really these are discovery sys default addrs ONLY useful for
 # when none is provided to a root actor on first boot.
-_default_lo_addrs: dict[
+_default_lo_addrs: dict[str, UnwrappedAddress] = {
-    str,
+    cls.proto_key: cls.get_root().unwrap()
-    UnwrappedAddress
+    for cls in _address_protos
-] = {
-    'tcp': TCPAddress.get_root().unwrap(),
-    'uds': UDSAddress.get_root().unwrap(),
 }
 
 
 def get_address_cls(name: str) -> Type[Address]:
-    return _address_types[name]
+    try:
+        return _address_types[name]
+    except KeyError:
+        raise NotImplementedError(
+            f'No IPC transport backend for {name!r} on this '
+            f'platform!\n'
+            f'(available: {list(_address_types)})\n'
+        )
 
 
 def is_wrapped_addr(addr: any) -> bool:
@@ -290,7 +303,14 @@ def default_lo_addrs(
     for an input transport key set.
 
     '''
-    return [
+    lo_addrs: list[UnwrappedAddress] = []
-        _default_lo_addrs[transport]
+    for transport in transports:
-        for transport in transports
+        try:
-    ]
+            lo_addrs.append(_default_lo_addrs[transport])
+        except KeyError:
+            raise NotImplementedError(
+                f'No default loopback addr for transport '
+                f'{transport!r} on this platform!\n'
+                f'(available: {list(_default_lo_addrs)})\n'
+            )
+    return lo_addrs

tractor/ipc/_server.py

@@ -62,19 +62,20 @@ from .. import log
 from ..discovery._addr import Address
 from ._chan import Channel
 from ._transport import MsgTransport
-from ._uds import UDSAddress
+
-from ._tcp import TCPAddress
 
 if TYPE_CHECKING:
     from ..runtime._runtime import Actor
     from ..runtime._supervise import ActorNursery
 
 
+from ._tcp import TCPAddress
+from ._uds import UDSAddress
+
 log = log.get_logger()
 
 _PRE_REG_HANDSHAKE_TIMEOUT: float = 10
 
-
 async def maybe_wait_on_canced_subs(
     uid: tuple[str, str],
     chan: Channel,

tractor/ipc/_types.py

@@ -18,17 +18,13 @@
 IPC subsys type-lookup helpers?
 
 '''
-from typing import (
+from typing import Type
-    Type,
-    # TYPE_CHECKING,
-)
-
-import trio
 import socket
+import trio
 
 from tractor.ipc._transport import (
     MsgTransportKey,
-    MsgTransport
+    MsgTransport,
 )
 from tractor.ipc._tcp import (
     TCPAddress,
@@ -37,37 +33,33 @@ from tractor.ipc._tcp import (
 from tractor.ipc._uds import (
     UDSAddress,
     MsgpackUDSStream,
+    HAS_UDS,
 )
 
-# if TYPE_CHECKING:
+# the UDS backend is importable everywhere but only *usable* when
-#     from tractor._addr import Address
+# `HAS_UDS` is `True`; otherwise the runtime registers TCP only.
-
-
 Address = TCPAddress|UDSAddress
 
-# manually updated list of all supported msg transport types
+# the available msg-transport backends on this host: TCP always,
-_msg_transports = [
+# UDS only where usable (`HAS_UDS`). The lookup maps below derive
+# from this single list via each backend's `codec_key` and
+# `address_type`: register a backend here and every map picks it up.
+_msg_transports: list[Type[MsgTransport]] = [
     MsgpackTCPStream,
-    MsgpackUDSStream
 ]
+if HAS_UDS:
+    _msg_transports.append(MsgpackUDSStream)
 
-
+# map a `MsgTransportKey` -> `MsgTransport` type
-# convert a MsgTransportKey to the corresponding transport type
+_key_to_transport: dict[MsgTransportKey, Type[MsgTransport]] = {
-_key_to_transport: dict[
+    (t.codec_key, t.address_type.proto_key): t
-    MsgTransportKey,
+    for t in _msg_transports
-    Type[MsgTransport],
-] = {
-    ('msgpack', 'tcp'): MsgpackTCPStream,
-    ('msgpack', 'uds'): MsgpackUDSStream,
 }
 
-# convert an Address wrapper to its corresponding transport type
+# map an `Address`-wrapper -> `MsgTransport` type
-_addr_to_transport: dict[
+_addr_to_transport: dict[Type[Address], Type[MsgTransport]] = {
-    Type[TCPAddress|UDSAddress],
+    t.address_type: t
-    Type[MsgTransport]
+    for t in _msg_transports
-] = {
-    TCPAddress: MsgpackTCPStream,
-    UDSAddress: MsgpackUDSStream,
 }
 
 
@@ -81,41 +73,51 @@ def transport_from_addr(
 
     '''
     try:
-        return _addr_to_transport[type(addr)]
+        addr_type = type(addr)
+        return _addr_to_transport[addr_type]
 
     except KeyError:
         raise NotImplementedError(
-            f'No known transport for address {repr(addr)}'
+            f'No known transport for address '
+            f'{addr!r}'
         )
 
 
 def transport_from_stream(
     stream: trio.abc.Stream,
-    codec_key: str = 'msgpack'
+    codec_key: str = 'msgpack',
 ) -> Type[MsgTransport]:
     '''
     Given an arbitrary `trio.abc.Stream` and a desired codec,
     find the corresponding `MsgTransport` type.
 
     '''
-    transport = None
+    transport: str|None = None
+
     if isinstance(stream, trio.SocketStream):
         sock: socket.socket = stream.socket
         match sock.family:
             case socket.AF_INET | socket.AF_INET6:
                 transport = 'tcp'
 
-            case socket.AF_UNIX:
+            # `HAS_UDS` short-circuits before `socket.AF_UNIX` on
+            # hosts where that constant is absent.
+            case fam if (
+                HAS_UDS
+                and
+                fam == socket.AF_UNIX
+            ):
                 transport = 'uds'
 
-            case _:
+            case fam:
                 raise NotImplementedError(
-                    f'Unsupported socket family: {sock.family}'
+                    f'Unsupported socket family: {fam}'
                 )
 
     if not transport:
         raise NotImplementedError(
-            f'Could not figure out transport type for stream type {type(stream)}'
+            f'Could not figure out transport type for stream type '
+            f'{type(stream)}'
         )
 
     key = (codec_key, transport)

tractor/ipc/_uds.py

@@ -26,11 +26,21 @@ from pathlib import Path
 import os
 import sys
 from socket import (
-    AF_UNIX,
     SOCK_STREAM,
     SOL_SOCKET,
     error as socket_error,
 )
+# NOTE, `AF_UNIX` is absent on Windows / any CPython built without
+# unix-domain-socket support. Keep this module importable
+# everywhere (so `UDSAddress` stays referenceable for type and
+# `isinstance()` checks plus registry lookups); the `AF_UNIX`-using
+# code paths below are runtime-only and are never reached when the
+# UDS backend is unusable (gated on `trio`'s `has_unix`, see
+# `HAS_UDS`).
+try:
+    from socket import AF_UNIX
+except ImportError:
+    AF_UNIX = None
 import struct
 from typing import (
     Any,
@@ -104,6 +114,16 @@ _SUN_PATH_LIMIT: int = (
 )
 
 
+# single source of truth for whether the UDS backend is usable on this
+# host. Windows can expose `AF_UNIX`, but this backend remains
+# POSIX-only until its credential and lifecycle paths are supported.
+HAS_UDS: bool = (
+    sys.platform != 'win32'
+    and
+    has_unix
+)
+
+
 def unwrap_sockpath(
     sockpath: Path,
 ) -> tuple[Path, Path]: