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Accepted
Deepak Sharma
Asked: 2025-01-07 18:49:33 +0800 CST

在监视任务中 Actor 的已发布值时，Swift 6 生成错误

  • 772

以下代码在 Xcode 中 Swift 6 语言版本下构建时出错。这是架构问题还是有简单的解决方法？类型Bool是，Sendable但它的发布者不是。

Non-sendable type 'Published<Bool>.Publisher' in implicitly asynchronous access to actor-isolated property '$isRecording' cannot cross actor boundary

import Foundation

final class Recorder {
    
    var writer = Writer()
    var isRecording = false
    
    func startRecording() {
        Task { [writer] in
            await writer.startRecording()
            print("started recording")
        }
    }
    
    func stopRecording() {
        Task { [writer] in
            await writer.stopRecording()
            print("stopped recording")
        }
    }
    
    func observeValues() {
        
        Task {
            for await value in await writer.$isRecording.values {
                isRecording = value
            }
        }
    }
}

actor Writer {
    @Published private(set) public var isRecording = false
    
    func startRecording() {
        isRecording = true
    }
    
    func stopRecording() {
        isRecording = false
    }
}

请参阅此屏幕截图以查看我看到的 AVCam 示例代码中的实际错误（唯一的修改是输入@preconcurrency）import AVFoundation。

请参阅此屏幕截图以了解我看到的 AVCam 示例代码中的实际错误（未经修改）

1 个回答

  1. Best Answer

    我不会@Published使用然后获取values，而是直接使用AsyncStream来传递值。AsyncStream如果流元素可发送，那么也是可发送的。

    @propertyWrapper
struct Streamed<T: Sendable> {
    private var continuation: AsyncStream<T>.Continuation
    
    var projectedValue: AsyncStream<T>
    
    var wrappedValue: T {
        didSet {
            continuation.yield(wrappedValue)
        }
    }
    
    init(wrappedValue: T) {
        self.wrappedValue = wrappedValue
        (projectedValue, continuation) = AsyncStream.makeStream()
        continuation.yield(wrappedValue)
    }
}

actor Writer {
    @Streamed private(set) public var isRecording = false
    
    func startRecording() {
        isRecording = true
    }
    
    func stopRecording() {
        isRecording = false
    }
}

    observedValues然后在

    @MainActor
func observeValues() {
    Task {
        for await value in await writer.$isRecording {
            isRecording = value
        }
    }
}

    请注意，为了isRecording = value安全起见，需要将observeValues整体Recorder隔离到全局参与者。

    • 1

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