[jacorb-developer] Unexpected behaviour in JacORB 3.6 and 3.6.1 (Bug 1011 and 1012)

[Hugo Roenick]

Hi guys.

Theres is a while since I noticed that the JacORB update to 3.6 caused one of our test case to fail, but I didn't manage to reserve the necessary time to isolate the problem and report to you guys.
Sorry about that.

Well, I finally did manage to save some time and I'm working on this on the last few days.
The problem is a little trick to explain, so I will try to be as clear that I can. 
I'm sorry in advance for the extension of this mail.

The main problem in this specific test is that we start to receive an unexpected error on client side. This is the stack trace is something like (this one is from the isolated demo that I created and will attach in a bug issue):

Exception in thread "main" java.util.NoSuchElementException
	at java.util.ArrayDeque.removeFirst(ArrayDeque.java:278)
	at java.util.ArrayDeque.pop(ArrayDeque.java:507)
	at org.jacorb.orb.portableInterceptor.ClientInterceptorIterator.invoke(ClientInterceptorIterator.java:169)
	at org.jacorb.orb.portableInterceptor.AbstractInterceptorIterator.iterate(AbstractInterceptorIterator.java:66)
	at org.jacorb.orb.portableInterceptor.ClientInterceptorIterator.iterate(ClientInterceptorIterator.java:79)
	at org.jacorb.orb.portableInterceptor.DefaultClientInterceptorHandler.invokeInterceptors(DefaultClientInterceptorHandler.java:331)
	at org.jacorb.orb.portableInterceptor.DefaultClientInterceptorHandler.handle_send_request(DefaultClientInterceptorHandler.java:135)
	at org.jacorb.orb.Delegate._invoke_internal(Delegate.java:1268)
	at org.jacorb.orb.Delegate.invoke_internal(Delegate.java:1171)
	at org.jacorb.orb.Delegate.invoke(Delegate.java:1159)
	at org.omg.CORBA.portable.ObjectImpl._invoke(ObjectImpl.java:475)
	at demo._DoorStub.canIComeIn(_DoorStub.java:119)
	at demo.door.DoorClient.main(DoorClient.java:41)

I checked that this kind of error does not occur in JacORB 3.5 and is present in versions 3.6 and 3.6.1.

This error is related to making 2 or more remote calls during send_request interception point and doing it while attending to a forward request attempt. (It probably is not a common scenario, but we used this strategy to build a handshake protocol between CORBA parties)

While isolating this problem I stumbled in another unexpected behaviour. Instead of making 2 or more calls inside the send_request interception point, just make 1 more call that is also going to receive an exception and resolve it through a forward_request. In this case I noticed that there is an extra send_request call and the previous one apparently is not completed (does not arrives in server side). 

Let me try to make myself clear with an example:

[client]											[server]
	---- calls A() ---->
	<---- NO_PERMISSION (op = A) ----
	
	receive_exception:
		do forward_request( op = A )

	---- calls A() ---->
		---- send_request( op = A )  ---->
			---- calls B() ---->
			<---- NO_PERMISSION (op = B) ----
			
			receive_exception:
				do forward_request( op = B )
			
			---- calls B() ---->
			<---- successful reply (op = B) ----
		--- complete the send_request( op = A) --->
	// "apparently this completed send_request does not arrives to the server"
	// why ???

	// an extra call is sent. Why??
	---- calls A() ---->
	<---- successful reply (op = A) ----


Placed two bug issues in bugzilla with the demo code (its the same demo, with a different case test enum configured in DoorClient.java):
 - Bug 1011 - NoSuchElementException while making remote calls while attending to a forward_request
 - Bug 1012 - Missed send_request while completing a forward request

Regards,
-- Hugo