recv hangs if there’s no timeout and connection closes

[JetForMe]

recv() is supposed to return a 0-length bytes object when the connection closes. But the check for bytes, although it tests the timeout, doesn’t test the connection status, and thus hangs forever if the connection closes.

[JetForMe]

This is a potential fix:

        while not self._available():
            if self._status in (wiznet5k.adafruit_wiznet5k.SNSR_SOCK_CLOSED, wiznet5k.adafruit_wiznet5k.SNSR_SOCK_CLOSE_WAIT):
                break

    @_check_socket_closed
    def recv(
        # pylint: disable=too-many-branches
        self,
        bufsize: int,
        flags: int = 0,
    ) -> bytes:
        """
        Receive data from the socket. The return value is a bytes object representing the data
        received. The maximum amount of data to be received at once is specified by bufsize.

        :param int bufsize: Maximum number of bytes to receive.
        :param int flags: ignored, present for compatibility.

        :return bytes: Data from the socket.
        """
        stamp = time.monotonic()
        while not self._available():
            if self._status in (wiznet5k.adafruit_wiznet5k.SNSR_SOCK_CLOSED, wiznet5k.adafruit_wiznet5k.SNSR_SOCK_CLOSE_WAIT):
                break
            if self._timeout and 0 < self._timeout < time.monotonic() - stamp:
                break
            time.sleep(0.05)
        bytes_on_socket = self._available()
        if not bytes_on_socket:
            return b""
        bytes_to_read = min(bytes_on_socket, bufsize)
        if self._sock_type == SOCK_STREAM:
            bytes_read = _the_interface.socket_read(self._socknum, bytes_to_read)[1]
        else:
            bytes_read = _the_interface.read_udp(self._socknum, bytes_to_read)[1]
        gc.collect()
        return bytes(bytes_read)