Class ExThread

tests/test_filelock.py:270–284

class ExThread(threading.Thread):
    def __init__(self, target: Callable[[], None], name: str) -> None:
        super().__init__(target=target, name=name)
        self.ex: _ExcInfoType | None = None

    def run(self) -> None:
        try:
            super().run()
        except Exception:  # pragma: no cover  # a worker that raises fails the test; a healthy run never lands here
            self.ex = sys.exc_info()

    def join(self, timeout: float | None = None) -> None:
        super().join(timeout=timeout)
        if self.ex is not None:
            raise RuntimeError from self.ex[1]  # pragma: no cover  # only a worker that raised gets re-raised here


# 100 threads x 100 acquisitions is thousands of lock cycles; the 20s default is tight on a loaded Windows runner.