createDelegate built its NSURLSessionDataDelegate with objc_allocateClassPair
and then sent it +alloc without ever calling objc_registerClassPair. The runtime
requires registration before a class pair can be used; everything up to then is
still being assembled. Register it, after the methods and the ivar go on.
The response header arrays were VLAs sized from the count the server sent, so a
response with enough headers walked the stack off the end, and one with no
headers at all declared zero-length VLAs, which is undefined by itself. Heap
now, and skipped when there's nothing to read.
The NSURLSession was also kept in the response without retaining it, while the
autorelease pool it came from is drained on the way out of the function. It only
survived because a session keeps itself alive while it has tasks running. Retain
it, release it when the response closes.
Finally, addMethod/addIvar signalled failure with assert alone, which is
compiled out in release - a delegate missing its methods would just never
receive data and the request would hang with nothing logged.
Henrik Rydgård
cb2de6317c