CoreData, Concurrency, and Background Context Confusion

Using Swift
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1

I don't understand why Example 1 fails to compile and Example 2 compiles just fine in swift 6?

Note in the following examples that gDataController.container is an NSPersistentContainer

Example 1:

try await gDataController.container.performBackgroundTask { bkContext in
	try bkContext.save()
}

The Example 1 error is:

:cross_mark: Sending value of non-Sendable type '(NSManagedObjectContext) throws -> ()' risks causing data races

However Example 2 compiles just fine:

Example 2:

let bkContext = gDataController.container.newBackgroundContext()
try bkContext.performAndWait {
	try bkContext.save()
}

It would appear to me that these are exactly opposite of my expectations. Clearly in Example 2, bkContext is being passed into the closure.

Can anyone explain this?

2

Did you manage to find out a solution to getting the first to compile? I'd like to use that because it uses the async and it returns a value.

3

Nope, sometimes it works and sometimes it does not. I've not been able to figure out the magic sauce.

So I do this, which is probably wrong:

try await gDataController.container.performBackgroundTask { @Sendable bkMOC in