prevent None struct to be used in to_io

diff --git a/remoto/lib/execnet/gateway_base.py b/remoto/lib/execnet/gateway_base.py
index 30e6e1acc325bbf00374ec5efe48cc837c0c3edf..45b2351afbfd8ca0751f994ef9facbc477508785 100644 (file)
--- a/remoto/lib/execnet/gateway_base.py
+++ b/remoto/lib/execnet/gateway_base.py
@@ -376,9 +376,10 @@ class Message:
         return Message(msgtype, channel, io.read(payload))
 
     def to_io(self, io):
-        header = struct.pack('!bii', self.msgcode, self.channelid,
-                             len(self.data))
-        io.write(header+self.data)
+        if struct.pack is not None:
+            header = struct.pack('!bii', self.msgcode, self.channelid,
+                                 len(self.data))
+            io.write(header+self.data)
 
     def received(self, gateway):
         self._types[self.msgcode](self, gateway)