Unsafe task-local binding #2222
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| ```swift | ||
| func order() async { | ||
| $wasabiPreference.unsafePushValue(.with) | ||
| defer { TL.$number.unsafePopValue() } |
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Where is TL.$number coming from? Shouldn't this be $wasabiPreference.unsafePopValue()?
| @WasabiPreference(.with) | ||
| func order() async { | ||
| // $wasabiPreference.unsafePushValue(.with) | ||
| // defer { TL.$number.unsafePopValue() } |
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Same here, I'm confused about the TL.$number.
| /// - SeeAlso: ``withValue(_:file:line:)`` | ||
| /// - SeeAlso: ``unsafePushValue(_:file:line:)`` | ||
| @inlinable | ||
| public func unsafePopValue(file: String = #fileID, line: UInt = #line) |
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Do you also want to include the body of this method?
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Nope, we're not showing implementation details -- it is swift runtime builtins
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In that case I'd remove the body from unsafePushValue as well: https://github.com/apple/swift-evolution/pull/2222/files/258dcb1baf3ca64625fa5de307cf86da5d562de1#diff-78f598930dd0a3b9e4f0bcb4c50b84efd89866f095a2bc84bd7193753b8a57cdR166
Co-authored-by: Moritz Lang <hi@slashmo.codes>
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| ```swift | ||
| func order() async { | ||
| $wasabiPreference.withValue(.with) { |
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Sorry, what is .with here? It is not mentioned anywhere in the text or declared in the examples—is this some existing concurrency API?
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It's the value set for the wasabiPreference task-local within the closure scope. I suppose there are .with and .without, but I think this should be written down as part of the proposal. CC @ktoso
The $taskLocal.withValue API is the existing (safe) API to bind task-local values.
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The Language Steering Group is going to sit on this until we figure out in the function-body macros proposal whether this sort of thing really has to be necessary. I think we're hoping that it doesn't. |
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Sounds good, agreed! I've put it into "draft" to signal that this isn't going to be reviewed for the time being. |
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This provides building blocks necessary to build tracing macros (or similar) which use body "preamble" macros.