[pygtk] ORBit and python

[Gustavo J. A. M. Carneiro]

On Ter, 2006-09-26 at 10:03 +1000, Russell Strong wrote:
> Hi,
> 
> I've been pulling my hair out the last couple of days trying to get a 
> simple python/ORBit example working.
> 
> The server code ( see below ) show the following error
> Traceback (most recent call last):
>   File "server", line 14, in increment
>     self.count += 1
> AttributeError: 'Counter' object has no attribute 'count'
> 
> Adding a line print dir(self) to increment shows there really is no 
> count. Huh???
> 
> The client ( see below ) shows:
> Traceback (most recent call last):
>   File "client", line 13, in ?
>     counter.increment()
> CORBA.UNKNOWN
> 
> HELP !!!
> 
> Client Code
> ----------------
> 
> #!/usr/bin/env python
> 
> import ORBit
> ORBit.load_file ('Test.idl')
> import CORBA, Test
> 
> orb = CORBA.ORB_init()
> ior = open('/tmp/orbit-python.ior').readline()
> counter = orb.string_to_object(ior)
> 
> for i in xrange(10001):
>         try:
>                 counter.increment()
>         except Test.Counter, data:
>                 print 'Overflow : ', data.count
> 
> 
> Server Code
> ----------------
> 
> #!usr/bin/env python
> 
> import ORBit
> ORBit.load_file('Test.idl')
> import CORBA, Test, Test__POA
> 
> class Counter(Test__POA.Counter):
> 
>         def __init__(self):
>                 Test__POA.Counter.__init__(self)
>                 self.count = 0
> 
>         def increment(self):
>                 self.count += 1
>                 if self.count > 10000:
>                         e = Test.TestInterface.Overflow()
>                         e.count = self.count
>                         raise Test.TestInterface.Overflow, e
> 
> orb = CORBA.ORB_init()
> poa = orb.resolve_initial_references("RootPOA")

If you change this code:

> ref = Counter()._this()

to this:

> counter = Counter()
> ref = counter._this()

Then it works (after you fix the rest of the code,
s/Test.TestInterface.Overflow/Test.Counter.Overflow/).

The reason is that this expression "Counter()._this()" creates a
Counter() servant, takes a CORBA object reference to it, but then the
servant's reference count drops to zero and the servant is deallocated
and deactivated.  So the client ends up receiving a reference to a dead
object.

I'm not completely sure yet, but this looks like a PyORBit bug.  Could
you open a bug report in bugzilla?  Thanks.

-- 
Gustavo J. A. M. Carneiro
<gjc at inescporto.pt> <gustavo at users.sourceforge.net>
The universe is always one step beyond logic.