Draft of debugging the multiple inheritance problems in km.

* Added __init__ methods to KernelManager classes.
* Played with multiple inheritance between the Qt and non-Qt
  classes.
* But, the prompt doesn't show up for the first line of input???

IPython/frontend/qt/kernelmanager.py

@@ -10,7 +10,13 b' from IPython.zmq.kernelmanager import KernelManager, SubSocketChannel, \\'
     XReqSocketChannel, RepSocketChannel
 from util import MetaQObjectHasTraits
 
-
+# When doing multiple inheritance from QtCore.QObject and other classes
+# the calling of the parent __init__'s is a subtle issue:
+# * QtCore.QObject does not call super so you can't use super and put
+#   QObject first in the inheritance list.
+# * QtCore.QObject.__init__ takes 1 argument, the parent. So if you are going
+#   to use super, any class that comes before QObject must pass it something
+#   reasonable.
 
 class QtSubSocketChannel(SubSocketChannel, QtCore.QObject):
 
@@ -106,7 +112,6 b' class QtRepSocketChannel(RepSocketChannel, QtCore.QObject):'
         QtCore.QObject.__init__(self)
         RepSocketChannel.__init__(self, *args, **kw)
 
-
 class QtKernelManager(KernelManager, QtCore.QObject):
     """ A KernelManager that provides signals and slots.
     """
@@ -124,6 +129,10 b' class QtKernelManager(KernelManager, QtCore.QObject):'
     xreq_channel_class = QtXReqSocketChannel
     rep_channel_class = QtRepSocketChannel
 
+    def __init__(self, *args, **kw):
+        QtCore.QObject.__init__(self)
+        KernelManager.__init__(self, *args, **kw)
+
     #---------------------------------------------------------------------------
     # 'KernelManager' interface
     #---------------------------------------------------------------------------

IPython/frontend/qt/util.py

@@ -11,6 +11,7 b' from IPython.utils.traitlets import HasTraits'
 MetaHasTraits = type(HasTraits)
 MetaQObject = type(QtCore.QObject)
 
+# You can switch the order of the parents here.
 class MetaQObjectHasTraits(MetaQObject, MetaHasTraits):
     """ A metaclass that inherits from the metaclasses of both HasTraits and
         QObject. 
@@ -18,8 +19,9 b' class MetaQObjectHasTraits(MetaQObject, MetaHasTraits):'
         Using this metaclass allows a class to inherit from both HasTraits and
         QObject. See QtKernelManager for an example.
     """
-
-    def __init__(cls, name, bases, dct):
-        MetaQObject.__init__(cls, name, bases, dct)
-        MetaHasTraits.__init__(cls, name, bases, dct)
+    # pass
+    # ???You can get rid of this, but only if the order above is MetaQObject, MetaHasTraits
+    # def __init__(cls, name, bases, dct):
+    #     MetaQObject.__init__(cls, name, bases, dct)
+    #     MetaHasTraits.__init__(cls, name, bases, dct)
         

IPython/zmq/kernelmanager.py

@@ -385,6 +385,7 b' class KernelManager(HasTraits):'
         self._rep_address = (LOCALHOST, 0) if rep_address is None else rep_address
         self.context = zmq.Context() if context is None else context
         self.session = Session() if session is None else session
+        super(KernelManager, self).__init__()
 
     #--------------------------------------------------------------------------
     # Channel management methods: