Thread.current is unnecessarily noasync

[weissi]

swift-corelibs-foundation/Sources/Foundation/Thread.swift

Line 85 in c28bf23

@available(*, noasync)

Thread.current is very useful as a debugging mechanism to understand the ordering of code running concurrently and/or in parallel. This is very useful to use from async functions.

Sure, the workaround is just

extension Thread {
    public static var currentThread: Thread {
        return Thread.current
    }
}

but that shouldn't be necessary.

[parkera]

Maybe it's useful for debugging, but it's wrong to conflate a task with a thread. Making this API available in async contexts seems like a mistake to me. @phausler did the original audit, though, so pulling him in for his opinion.

[weissi]

Maybe it's useful for debugging, but it's wrong to conflate a task with a thread. Making this API available in async contexts seems like a mistake to me. @phausler did the original audit, though, so pulling him in for his opinion.

Sure, it's important to not conflate tasks & threads, just like it was always important to not conflate DispatchQueues and threads. And yet we didn't try to ban you calling Thread.current from a DispatchQueue. And it's really important for debugging (and sometimes even when logging around problematic sections).

Also: Allowing it anywhere doesn't cause any hard, we're using it anyway but today we have to work around it (with that extension Thread)