[qemu-xen staging] python/qmp.py: Do not return None from cmd_obj

[patchbot@xxxxxxx]

commit ef5d474472426eda6abf8128cdb1d026af94862b
Author:     John Snow <jsnow@xxxxxxxxxx>
AuthorDate: Fri Jul 10 01:22:08 2020 -0400
Commit:     Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
CommitDate: Tue Jul 14 22:22:22 2020 +0200

    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: John Snow <jsnow@xxxxxxxxxx>
    Reviewed-by: Kevin Wolf <kwolf@xxxxxxxxxx>
    Message-Id: <20200710052220.3306-5-jsnow@xxxxxxxxxx>
    Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
---
 python/qemu/qmp.py | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/python/qemu/qmp.py b/python/qemu/qmp.py
index aa8a666b8a..ef3c919b76 100644
--- a/python/qemu/qmp.py
+++ b/python/qemu/qmp.py
@@ -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
+        self.__sock.sendall(json.dumps(qmp_cmd).encode('utf-8'))
         resp = self.__json_read()
+        if resp is None:
+            raise QMPConnectError("Unexpected empty reply from server")
         self.logger.debug("<<< %s", resp)
         return resp
 
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging