Commit ef5d4744 authored by John Snow's avatar John Snow Committed by Philippe Mathieu-Daudé
Browse files

python/qmp.py: Do not return None from cmd_obj 



This makes typing the qmp library difficult, as it necessitates wrapping
Optional[] around the type for every return type up the stack. At some
point, it becomes difficult to discern or remember why it's None instead
of the expected object.

Use the python exception system to tell us exactly why we didn't get an
object. Remove this special-cased return.

Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Message-Id: <20200710052220.3306-5-jsnow@redhat.com>
Signed-off-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
parent e3a23b48

python/qemu/qmp.py

+5 −9
Original line number Diff line number Diff line
@@ -225,22 +225,18 @@ class QEMUMonitorProtocol: 
        self.__sockfile = self.__sock.makefile(mode='r')

        return self.__negotiate_capabilities()



    def cmd_obj(self, qmp_cmd):

    def cmd_obj(self, qmp_cmd: QMPMessage) -> QMPMessage:

        """

        Send a QMP command to the QMP Monitor.



        @param qmp_cmd: QMP command to be sent as a Python dict

        @return QMP response as a Python dict or None if the connection has

                been closed

        @return QMP response as a Python dict

        """

        self.logger.debug(">>> %s", qmp_cmd)

        try:

        self.__sock.sendall(json.dumps(qmp_cmd).encode('utf-8'))

        except OSError as err:

            if err.errno == errno.EPIPE:

                return None

            raise err

        resp = self.__json_read()

        if resp is None:

            raise QMPConnectError("Unexpected empty reply from server")

        self.logger.debug("<<< %s", resp)

        return resp