Added overrides for designated initializers in all classes as required by XCode 7 compiler

[javiertoledo]

I don’t know if this is the kind of solution you expect, I see it more as a quick patch than a good solution, as there are some warnings about deferred NULL pointers. Any ideas for better defaults for C structs would be really appreciated.

[phatblat]

Most values passed to the designated initializers should not be null, unless they are documented as an optional value. Object parameters are also tagged with nonnull if they are optional, but struct parameters don't have an equivalent attribute. The GT* objects are not going to behave correctly (and will most likely crash) without the required dependencies.

In short, the -init method should not be used on most of the objects in this framework. Xcode 7 is highlighting a gap in the API where these methods are still available since they are inherited from NSObject.

I had started on some work to make these -init methods non-functional, but then came across NS_ENFORCE_NSOBJECT_DESIGNATED_INITIALIZER which may actually be the simplest way to deal with this.

[joshaber]

Thanks! As a temporary solution goes, this one has a pretty big footprint 😧

I can't find much info on NS_ENFORCE_NSOBJECT_DESIGNATED_INITIALIZER besides the fact that it exists. How does it behave?

[phatblat]

I don't think there's any docs on NS_ENFORCE_NSOBJECT_DESIGNATED_INITIALIZER yet. I found it mentioned in the Dev Forums, but you can see it in the NSObject.h file of the OS X 10.11 or iOS 9 SDKs:

Looks like it is simply a flag you can use to disable the NS_DESIGNATED_INITIALIZER annotation on -init. So, it will make Xcode 7 stop complaining about not implementing -init, but it won't prevent calls to it.

[javiertoledo]

I think that the ideal solution would be to make init methods from the superclass unavailable, but it looks like that’s not possible...

Searching for more info I found this answer from someone at Apple to the same question https://forums.developer.apple.com/message/15575#15575

As we can’t just wipe out the superclass initializers, marking them as “unavailable” and throwing an exception when they’re accessed looks for me like a better approach than just disabling the warnings or implementing methods with nil objects that doesn’t make sense...

What do you think? If you like this approach I can close this PR and submit a second one later with the change.

[javiertoledo]

I’ve submitted the change I told you about before in PR #477, so I close this one, cheers!