diff mbox series

[v4,04/16] python/qmp.py: Do not return None from cmd_obj

Message ID 20200626204133.14500-5-jsnow@redhat.com
State Superseded
Headers show
Series [v4,01/16] python/qmp.py: Define common types | expand

Commit Message

John Snow June 26, 2020, 8:41 p.m. UTC 
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@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
---
 python/qemu/qmp.py | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)
diff mbox series

Patch

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 @@  def accept(self, timeout=15.0):
         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