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observe should take @isolated(any) functions #306

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Merged
merged 1 commit into from
Sep 10, 2025
Merged

observe should take @isolated(any) functions #306

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2 changes: 1 addition & 1 deletion Sources/SwiftNavigation/NSObject+Observe.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,7 @@
public func observe(
_ apply: @escaping @MainActor @Sendable (_ transaction: UITransaction) -> Void
) -> ObserveToken {
let token = SwiftNavigation.observe { transaction in
let token = SwiftNavigation._observe { transaction in
MainActor._assumeIsolated {
apply(transaction)
}
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33 changes: 8 additions & 25 deletions Sources/SwiftNavigation/Observe.swift
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Expand Up @@ -56,10 +56,9 @@ import ConcurrencyExtras
/// - Returns: A token that keeps the subscription alive. Observation is cancelled when the token
/// is deallocated.
public func observe(
isolation: (any Actor)? = #isolation,
@_inheritActorContext _ apply: @escaping @Sendable () -> Void
@_inheritActorContext _ apply: @escaping @isolated(any) @Sendable () -> Void
) -> ObserveToken {
observe(isolation: isolation) { _ in apply() }
observe { _ in Result(catching: apply).get() }
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This is a trick similarly employed by the Observations type to convert an @isolated(any) to a synchronous function. I'm not sure if there is a more legit way to assume the isolation of a closure to perform it synchronously.

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@maximkrouk maximkrouk Sep 24, 2025 •
edited
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I'm fixing conflicts for #286 and looks like this implementation gives a bunch of warnings on Xcode 26 beta 4 🤔

Screenshot 2025-09-24 at 12 58 04 PM

Converting @isolated(any) function of type '@isolated(any) @Sendable (UITransaction) -> Void' to synchronous function type '@Sendable (UITransaction) -> Void' is not allowed; this will be an error in a future Swift language mode 🤔

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@maximkrouk These warnings are fine. They even exist in Swift's Observation framework. Luckily they don't show up downstream.

}

/// Tracks access to properties of an observable model.
Expand All @@ -72,37 +71,21 @@ import ConcurrencyExtras
/// - Returns: A token that keeps the subscription alive. Observation is cancelled when the token
/// is deallocated.
public func observe(
isolation: (any Actor)? = #isolation,
@_inheritActorContext _ apply: @escaping @Sendable (_ transaction: UITransaction) -> Void
@_inheritActorContext
_ apply: @escaping @isolated(any) @Sendable (_ transaction: UITransaction) -> Void
) -> ObserveToken {
let actor = ActorProxy(base: isolation)
return observe(
_observe(
apply,
task: { transaction, operation in
Task {
await actor.perform {
operation()
}
await operation()
}
}
)
}
#endif

private actor ActorProxy {
let base: (any Actor)?
init(base: (any Actor)?) {
self.base = base
}
nonisolated var unownedExecutor: UnownedSerialExecutor {
(base ?? MainActor.shared).unownedExecutor
}
func perform(_ operation: @Sendable () -> Void) {
operation()
}
}

func observe(
func _observe(
_ apply: @escaping @Sendable (_ transaction: UITransaction) -> Void,
task: @escaping @Sendable (
_ transaction: UITransaction, _ operation: @escaping @Sendable () -> Void
Expand Down Expand Up @@ -141,7 +124,7 @@ func observe(
private func onChange(
_ apply: @escaping @Sendable (_ transaction: UITransaction) -> Void,
task: @escaping @Sendable (
_ transaction: UITransaction, _ operation: @escaping @Sendable () -> Void
_ transaction: UITransaction, _ operation: @escaping @isolated(any) @Sendable () -> Void
) -> Void
) {
withPerceptionTracking {
Expand Down