Function _wait_for_ready_signal

Lib/profiling/sampling/cli.py:220–247

Wait for the ready signal from the subprocess, checking for early death.

(sync_sock, process, timeout)

def _wait_for_ready_signal(sync_sock, process, timeout):
    """Wait for the ready signal from the subprocess, checking for early death."""
    deadline = time.monotonic() + timeout
    sel = selectors.DefaultSelector()
    sel.register(sync_sock, selectors.EVENT_READ)

    try:
        while True:
            _check_process_died(process)

            remaining = deadline - time.monotonic()
            if remaining <= 0:
                raise socket.timeout("timed out")

            if not sel.select(timeout=min(0.1, remaining)):
                continue

            conn, _ = sync_sock.accept()
            try:
                ready_signal = conn.recv(_RECV_BUFFER_SIZE)
            finally:
                conn.close()

            if ready_signal != _READY_MESSAGE:
                raise RuntimeError(f"Invalid ready signal received: {ready_signal!r}")
            return
    finally:
        sel.close()


def _run_with_sync(original_cmd, suppress_output=False):