Cannot serialize integers in Mac OS X 10.7

[johnezang]

Cannot serialize integers in Mac OS X 10.7

[johnezang]

After working with Andy on this bug (thanks @andypotion!), we were able to determine the cause of the problem.

However, since this is a bug that is specific to Mac OS X 10.7 / Lion, there are various NDA issues involved in discussing the problem publicly.

A work-around is known, but there's a legitimate question as to whether or not this is a bug in JSONKit or not. It's not clear if the work around should be checked in or if the problem should be resolved "up stream" from JSONKit, so to speak.

[johnezang]

This is likely a duplicate of issue #9.

[snej]

JSONKit is groping into an NSNumber object to dereference the 'isa' field. As far as I know this is not kosher since it makes assumptions about object memory layout that Apple could change in future OS versions, including Lion. I don't think you can assign blame upstream to Foundation.

This is probably faster than using the Obj-C runtime API to look up the class, but I don't think you can continue to do it, at least not in these hypothetical future OS versions/configurations where Apple may or may not have changed the layout of certain objects. You might need to use #ifdefs to fall back to safer, if slower, techniques.

[snej]

Now that Lion is no longer under NDA, could someone please post the workaround as a patch?

[hiltonc]

I'm also running into this problem. Anyone have a fix?

[snej]

My current workaround is to use NSJSONSerialization instead, when it's available. I do a runtime check to look up the class by name, and then call it if it's there instead of JSONKit.

[0xced]

I guess that Tagged pointers and fast-pathed CFNumber integers in Lion is the cause of this problem.

[andypotion]

I just submitted a pull request for this. People needing the fix ASAP should check out my fork.

[johnezang]

Fixed in commit c2ef692.