conformsToProtocol over DO

[Philip Mötteli]

Hi


I have a heavy crash, that I do not understand why:
I send from a client program the following message:

        [aUser conformsToProtocol:@protocol(UserProtocol)];


This makes my server crash in

        #2 in +[NSObject conformsToProtocol:aProtocol] at NSObject.m:1286


where the protocol list gives something probably wrong:

        (gdb) print *aProtocol
	$3 = {isa = 0x4022c680, protocol_name = 0x0, protocol_list = 
0c8165c78, instance_methods = 0x0, class_methods = 0x1}
        (gdb) print *aProtocol->protocol_list
        $2 = {next = 0x40228580, count = 257, list = {0x0}}


Count is surely wrong and the protocol name of the first protocol too.
So the program crashes with somewhere in libc:

        #0 in strcmp () from /lib/i686/libc.so.6
        #1 in -[Protocol conformsTo:] () from /usr/lib/libobjc.so.1
        #2 in +[NSObject conformsToProtocol:] at NSObject.m:1286
        #3 in -[NSObject conformsToProtocol:] at NSObject.m:1309
        #4 in __builtin_avcall () from /usr/lib/libavcall.so.0
        #5 in GSFFCallInvokeWithTargetAndImp at GSFFCallInvocation.m:638
        #6 in callframe_do_call at callframe.m:442
	#7 in -[NSConnection(Private) _service:forwardForProxy:] at 
NSConnection.m:2390
	#8 in -[NSConnection(Private) handlePortMessage:] at 
NSConnection.m:2149
        #9 in -[NSSocketPort handlePortMessage:] at NSSocketPort.m:1712
	#10 in -[GSTcpHandle receivedEvent:type:extra:forMode:] at 
NSSocketPort.m:1021
	#11 in -[NSSocketPort receivedEvent:type:extra:forMode:] at 
NSSocketPort.m:1864
        #12 in -[GSRunLoopCtxt pollUntil:within:] at NSRunLoop.m:835
        #13 in -[NSRunLoop acceptInputForMode:beforeDate:] at NSRunLoop.m:1960
        #14 in -[NSRunLoop runMode:beforeDate:] at NSRunLoop.m:2030
        #15 in -[NSRunLoop runUntilDate:] at NSRunLoop.m:2051
        #16 in -[NSRunLoop run] at NSRunLoop.m:2039
        #17 in main (argc=1, argv=0xbffff434) at main.m:62


if I replace the call to -conformsToProtocol: with

        [aUser respondsToSelector:@selector(loginName)]

it works.


Does anybody have an idea, why this crashes? Or why perhaps the 
protocol is not correctly sent over the wire?


Thanks
Phil