How to mark methods to be invoked only from the main thread in Obj-C?

I'm experimenting with the new Xcode 9 Main Thread Checker

This is pretty neat. I'd like to now mark / annotate my Obj-C methods to be invoked only from the main thread so the Main Thread Checker can kick-in automatically when attached to the debugger. I can't find any way to do this.

Solution

You can't (see update). But you could use an assert to do it manually (like PSPDFKit does for example)

assert(Thread.isMainThread, "Method must be called from the MainThread only!")

Update:

There's no way. Tweet from an employee:

unfortunately not; you cannot teach Main Thread Checker about you APIs (CC @kubamracek)

by @zaks_anna (Program analysis @apple)

Update2: There's an open radar being tracked by Apple, with ID#32659599. So hopefully, it will be implemented soon™.