[saagarjha]

Yeah, I'm not sure how far explicitly restricting the list of classes you can instantiate will go because of class clusters, etc which make it basically impossible to actually create "just" an NSString or NSData. However, it's still possible to have "secure" decoding if all subclasses preserves the semantics of their superclass, since applications will not be able to tell the difference. The issue here is that some classes did things that were outright incorrect with regards to their subclassing contract, and NSCoding made it possible for these poorly-written classes to be instantiated in unexpected contexts. (Oh, and thanks for fixing your formatting.)

[olliej]

XPC requires a specific set of classes to be enumerated outside the core datatypes, and that is something bounded. There is no part of your software that should ever be enumerating anything other than a deliberate concrete type. That's how we got into this mess in the first place :D

[re formatting: my desire to indent bullet points is matched only by HNs desire to then make each bullet point a single line \o/]