Allow .onReceive to accept any type of AsyncSequence. (#8)

.swiftpm/xcode/xcshareddata/xcschemes/AsyncValue.xcscheme

@@ -0,0 +1,67 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1400"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "AsyncValue"
+               BuildableName = "AsyncValue"
+               BlueprintName = "AsyncValue"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AsyncValue"
+            BuildableName = "AsyncValue"
+            BlueprintName = "AsyncValue"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

AsyncValueTestApp/TestPlans/AllTests.xctestplan

@@ -16,15 +16,13 @@
   },
   "testTargets" : [
     {
-      "parallelizable" : true,
       "target" : {
         "containerPath" : "container:AsyncValueTestApp.xcodeproj",
         "identifier" : "2AA580C628C2FFD7006EE900",
         "name" : "AsyncValueTestAppUITests"
       }
     },
     {
-      "parallelizable" : true,
       "target" : {
         "containerPath" : "container:..",
         "identifier" : "AsyncValueTests",

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.5
+// swift-tools-version: 5.7
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription

README.md

@@ -130,7 +130,7 @@ class MyObservableObject: ObservableObject {
 }
 ```
 
-There is also an `.onRecieve(stream:perform:)` view modifier that allows you to respond to changes from an @AsyncValue
+There is also an `.onRecieve(sequence:perform:)` view modifier that allows you to respond to changes from any AsyncSequence.
 
 ```swift
 struct MyView: View {

Sources/AsyncValue/View+AsyncValue.swift

@@ -10,47 +10,69 @@
 import SwiftUI
 
 public extension View {
-    /// Adds a modifier for this view that fires an action when a specific `AsyncValue` changes.
+    /// Adds a modifier for this view that fires an action when a specific `AsyncSequence` yields new values.
     /// - Parameters:
-    ///   - stream: the async stream to recieve updates from
+    ///   - sequence: the async sequence to recieve updates from
     ///   - handler: handler for new values
     /// - Returns: some View
     ///
     /// This view modifier works very similarly to `.onReceive(publisher:perform:)` and `.onChange(value:perform:)`
     ///
+    /// A warning will be printed to the console if the provided `AsyncSequence` throws an error. And no new values will be returned.
+    /// As such, it is recommended that `AsyncStream` is used rather than a custom `AsyncSequence` implementation.
+    ///
     /// ```swift
     ///  struct MyView: View {
     ///     var body: some View {
     ///         Text("Hello World!")
     ///             .onReceive(myService.$myValue) { value in
     ///                 print("The value changed to: \(value)")
     ///             }
+    ///             .onReceive(myService.myStream) { newValue in
+    ///                 print("My stream value changed to: \(newValue)")
+    ///             }
     ///     }
     ///  }
     ///
     ///  class MyService: ObservableObject {
     ///     @AsyncValue var myValue: String = "Test" {
     ///         willSet { objectWillChange.send() }
     ///     }
+    ///
+    ///     lazy var myStream: AsyncStream<Int> = {
+    ///         // initialize and return some async stream here
+    ///     }()
     ///  }
     /// ```
-    @ViewBuilder func onReceive<Value>(
-        _ stream: AsyncStream<Value>,
-        perform handler: @escaping (Value) async -> Void
+    @ViewBuilder func onReceive<Sequence: AsyncSequence>(
+        _ sequence: Sequence,
+        perform handler: @escaping (Sequence.Element) async -> Void
     ) -> some View {
         if #available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *) {
             task {
-                for await value in stream {
-                    await handler(value)
+                do {
+                    for try await value in sequence {
+                        await handler(value)
+                    }
+                } catch is CancellationError {
+                    // cancellation errors are valid and we can ignore them.
+                } catch {
+                    Self.printErrorWarning(error: error, sequence: sequence, function: #function, line: #line, file: #file)
                 }
             }
         } else {
             var task: Task<Void, Never>? = nil
 
             onAppear {
                 task = Task {
-                    for await value in stream {
-                        await handler(value)
+                    do {
+                        for try await value in sequence {
+                            await handler(value)
+                        }
+                    } catch is CancellationError {
+                        // cancellation errors are valid and we can ignore them.
+                    } catch {
+                        Self.printErrorWarning(error: error, sequence: sequence, function: #function, line: #line, file: #file)
                     }
                 }
             }
@@ -59,6 +81,21 @@ public extension View {
             }
         }
     }
+
+    private static func printErrorWarning(
+        error: Error,
+        sequence: any AsyncSequence,
+        function: StaticString = #function,
+        line: Int = #line,
+        file: StaticString = #file
+    ) {
+        print("""
+        [AsyncValue] - warning: usage of .onReceive(sequence:handler:) with unhandled throwing sequence at: \(file) \(function) \(line)
+        The AsyncSequence throwing the error: \(type(of: sequence))
+        The error has been caught here to help with debugging purposes: \(String(describing: error))
+        Please handle any errors thrown in your custom AsyncSequence implementation, or try using AsyncStream instead.
+        """)
+    }
 }
 
 #endif