[3.0.0beta1] Crash on observing NSProgress

[piercifani]

Hello,

Sorry to bug again, but I'm finding another crash when (attempting) to observe the progress of a task. I created a gist that again reproduces the crash.

Thanks for your time and I can't thank you enough for your work on this library!

[zwaldowski]

It's no bother at all.

I'm sorry to say this issue is in the code your posted. ProgressObserver.observeValue(forKeyPath:of:change:context:) is implemented as:

    public func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [String : Any]?, context: UnsafeMutableRawPointer?)

In Swift 3.0, at least, it should be:

    override public func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?)

[piercifani]

I'm sorry but I'm seeing the same crash. Updated gist with fix to the observeValue method here.

[zwaldowski]

You started making other changes to the code! 😁

A Progress instance needs to be created with the discreteProgress(totalUnitCount:) factory method. I'll see what I can do about working around requiring this, or if nothing else documenting it better. Thanks.

[piercifani]

Hey Zach! Yes, I did change the code that created the Progress instances as a way of trying out different approaches, and it inadvertently got pushed to the gist, sorry about that.

I am still seeing issue in my real app, but for now I think it's related to my code. I'll dig deeper to find that out.

Thanks a lot!

PS: Yeah, it'll be great to have documented how to use the progress tracking feature of Task