requestFactory: NPE while traversing local read-only proxies

[juli...@googlemail.com]

Hi,

I've recently set up remote logging which now gives me more visibility
on client-side bugs. One problem that I've discovered this way, but
never ran into myself, are spurious errors like the ones attached
below. As you can see, the stack trace isn't always identical but it
usually looks like an NPE somewhere in AbstractRequestContext.doFire.

Now, my understanding is that this might have to do with the
requestContext looking for any changes to local proxies. What baffles
me, though, is that for the specific RequestContext involved in these
errors the entities are never edited - the corresponding proxy class
doesn't even have setters, and edit() is never called. The calls in
question here are purely for getting data from the server
(specifically, a total entity count and one result page, for
populating a page of a CellTable). That's why I'm not sure why
getVersion would even have to be called on the client side at all.

I've double-checked that all arguments to the count and list
operations are non-null.

So far I don't know how to reproduce this error or else I would try to
condense it into a test case. I'm hoping you might have an idea of
where I could start looking? Also, is there any way I can make the
stack traces more informative or enable other relevant debug output?

Thanks.

2011-03-03 13:49:22,399 ERROR [redacted.client2.Redacted] - Uncaught
Exception
java.lang.Throwable: (TypeError): dynamicCast($getWrapped(this
$static.this$0), 420) is null
stack: $getVersion_0([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:42867
traverseProperties_14([object Object],[object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:42835
$traverse([object Object],[object Object],[object Object])@http://
redacted/redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:6485
encodeForJsoPayload([object Object],[object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:31332
encode_1([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:31322
$doFire([object Object],null)@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:6836
$fire([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:6864
$updateTable([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:12395
$onEntityUpdated_0([object Object],[object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:13757
execute_8()@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:14509
runScheduledTasks([object Array],[object Array])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:33076
$flushPostEventPumpCommands([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:32998
execute_50()@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:33128
execute_49([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:33030
entry0(execute_49,[object XPCCrossOriginWrapper],[object
Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:32920
([object Object])@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:32905
(1)@http://redacted/
redacted2/2411BB0FEDEB3CF297698EEE5A91AE69.cache.html:33094

2011-03-03 11:26:06,170 ERROR [redacted.client2.Redacted] - Uncaught
Exception
java.lang.Throwable: (TypeError): dynamicCast($getWrapped(this
$static.this$0), 420) is null
stack: $setInvocations([object Object],[object Object])@http://
redacted/redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:42886
$doFire([object Object],null)@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:6836
$fire([object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:6864
$updateTable([object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:12395
$onEntityUpdated_0([object Object],[object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:13757
execute_8()@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:14529
runScheduledTasks([object Array],[object Array])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:33088
$flushPostEventPumpCommands([object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:33010
execute_50()@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:33140
execute_49([object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:33042
entry0(execute_49,[object XPCCrossOriginWrapper],[object
Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:32932
([object Object])@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:32917
(11)@http://redacted/
redacted2/60ADBFDB7F1A7A4BFF0BF2BFD8E2F9E4.cache.html:33106