b48cc47a4c
Python 3.14 moves initializer state into a worker context. The old worker arguments fail on the first submission to a fresh executor. Use the current stdlib worker signature while preserving daemon shutdown and per-submission profile isolation. Cover worker initialization and context isolation on reused threads. Verified on Python 3.14.7: 41 focused tests pass through scripts/run_tests.sh. Ruff and diff checks pass. Packaged release verification remains pending.
55 lines
2.2 KiB
Python
55 lines
2.2 KiB
Python
"""Shared daemon-thread ThreadPoolExecutor.
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Stdlib workers are non-daemon AND registered in ``_threads_queues``, whose atexit
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hook joins every worker even after ``shutdown(wait=False)`` — one wedged worker
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(tool blocked on network I/O, hung provider, stuck subagent) blocks interpreter
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exit forever. This variant spawns daemon workers and skips that registration.
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Use it for best-effort/interruptible work that must never hold the process open;
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NOT for work that must complete before exit (durable writes belong on foreground
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threads with explicit bounded joins).
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"""
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from __future__ import annotations
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import threading
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import weakref
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from concurrent.futures import ThreadPoolExecutor
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from concurrent.futures.thread import _worker
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from contextvars import copy_context
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__all__ = ["DaemonThreadPoolExecutor"]
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class DaemonThreadPoolExecutor(ThreadPoolExecutor):
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"""ThreadPoolExecutor variant whose workers do not block process exit."""
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def submit(self, fn, /, *args, **kwargs):
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"""Keep each task in its caller's profile scope, even on a reused worker.
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Thread-start context cannot track later submissions from other profiles
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(#54937). The stdlib worker context manages initialization, not contextvars.
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"""
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ctx = copy_context()
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def _run_with_context(*call_args, **call_kwargs):
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return ctx.run(fn, *call_args, **call_kwargs)
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return super().submit(_run_with_context, *args, **kwargs)
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def _adjust_thread_count(self) -> None:
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# Match CPython 3.14 worker startup, but keep abandoned work out of the
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# interpreter's atexit joins: daemon=True and no _threads_queues entry.
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if self._idle_semaphore.acquire(timeout=0):
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return
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def weakref_cb(_, q=self._work_queue):
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q.put(None)
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num_threads = len(self._threads)
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if num_threads < self._max_workers:
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thread_name = "%s_%d" % (self._thread_name_prefix or self, num_threads)
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t = threading.Thread(
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name=thread_name, target=_worker, daemon=True,
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args=(weakref.ref(self, weakref_cb), self._create_worker_context(), self._work_queue),
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)
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t.start()
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self._threads.add(t)
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