Awaiting APIs
So, this is the first time I am filling a bug report against a whole WWDC talk asking for its retraction for misleading info and describing unimplemented features. It’s the “Efficiency awaits: Background tasks in SwiftUI”.
Well, they did say that it “awaits.”
The talk describes
.backgroundTask(.urlSession("...")) {}modifier, and leaves its body empty - because there is no valid code that could work there. This part seems to be entirely unimplemented, probably planned to be finished for WWDC 22, but never completed even 3 years later.If you google the code, you will find many developers having spent hours and days trying to implement the solution from this talk, only to end up in dead end.
More details are in this forum post.
I recently wasted time on a similar issue, trying to get Core Data’s indexed:by: function to work. It’s supposed to be the equivalent of this. I wasn’t able to find the function in the documentation, but I had notes on it from WWDC 2017 Session 210, where it was displayed on a slide and also live-demoed. This wouldn’t be the first time the documentation was missing. But in this case it looks like the implementation is also missing, i.e. that the function was pulled after the demo. I don’t know why—it seems like a straightforward feature that they already had working. (Perhaps a hint that it was in flux is that the order of the function’s arguments are backwards in the slide vs. in the demo code.)
Previously:
