Re: Unresolved Issues with libxml2

[Doug Simons]

Thanks, Fred!

I can confirm that your change fixes the crash for me. I'll see about providing 
a test case that demonstrates my issue #1 soon.

Cheers,

Doug

On Apr 4, 2012, at 3:38 PM, Fred Kiefer wrote:

> Hi Doug,
> 
> thank you for providing this test code. I could reproduce the problem
> and have committed a simplified version of your test code to SVN. Plus a
> solution to the problem.
> It turned out to be caused by the private document I use to hold
> detached nodes. This together with the code that allows the document to
> provide replacement classes for node types could lead to a segmentation
> fault. I fixed this by not allowing the private document to be
> considered in class replacements. Please test again with SVN code.
> 
> If you are interested in a solution to your issue #1, please provide some 
> test code that shows this behaviour.
> 
> Cheers,
> Fred
> 
> On 04.04.2012 00:56, Doug Simons wrote:
>> Hello Fred,
>> 
>> Thanks for all of your work on the XML classes, and for your summary
>> of the areas that still need attention. My original issue #1 (at the
>> beginning of this thread) is still outstanding as well. My issues #2
>> and #3 have been resolved -- thanks!
>> 
>> As it happens, I managed to get back to this yesterday, and spent
>> most of yesterday and today trying to isolate the memory crash I was
>> seeing. It turns out there were (unfortunately) a lot of red herrings
>> in my earlier description of the sequence that leads to the crash,
>> and obviously some missing steps or you would have been able to
>> reproduce it. I was finally able to reproduce the crash myself and
>> create a minimal test case for this problem.
>> 
>> Unfortunately, I've now spent too much time on this to do much more
>> with it. I appreciate that you've spent a lot of time on this code,
>> too, but I hope you might be able to figure out how to resolve this
>> problem. If not, we will revert to a slightly earlier version of the
>> NSXML* code for now, which doesn't crash in this way.
>> 
>> Regards,
>> 
>> Doug
>> 
>> Here is my crashTest:
>> 
>> #import "ObjectTesting.h" #import<Foundation/NSAutoreleasePool.h>
>> #import<Foundation/NSXMLDocument.h>
>> #import<Foundation/NSXMLElement.h>
>> 
>> int main() { NSAutoreleasePool *arp = [NSAutoreleasePool new];
>> NSXMLDocument *node; NSXMLDocument *node2; NSXMLElement *elem;
>> NSXMLElement *elem2; NSXMLNode *child; NSXMLNode *child2;
>> 
>> NSString *simpleXML = @"<num>6</num>";
>> 
>> // create two documents (containing root elements with the same name
>> ("num") -- may be significant?) node = [[NSXMLDocument alloc]
>> initWithXMLString:simpleXML options:0 error:NULL]; PASS(node != nil,
>> "document was initialized from a string");
>> 
>> node2 = [[NSXMLDocument alloc] initWithXMLString:simpleXML options:0
>> error:NULL]; PASS(node2 != nil, "document 2 was initialized from a
>> string");
>> 
>> // detach the root elements from their documents elem = [node
>> rootElement]; //  PASS_EQUAL([elem XMLString], simpleXML, "root
>> element is correct"); [elem detach];
>> 
>> elem2 = [node2 rootElement]; //  PASS_EQUAL([elem2 XMLString],
>> simpleXML, "root element 2 is correct"); [elem2 detach];
>> 
>> // now, simply accessing the text node child of each element leads to
>> a CRASH child = [elem childAtIndex:0]; child2 = [elem2
>> childAtIndex:0];
>> 
>> [node release]; [node2 release];
>> 
>> [arp release]; arp = nil;
>> 
>> return 0; }
>