Fix ForEach Collection change rendered View correctness

.gitignore

@@ -12,3 +12,4 @@ DerivedData/
 .swiftpm
 vcpkg_installed/
 *.trace
+notes.json

Examples/Bundler.toml

@@ -64,3 +64,8 @@ version = '0.1.0'
 identifier = 'dev.swiftcrossui.HoverExample'
 product = 'HoverExample'
 version = '0.1.0'
+
+[apps.ForEachExample]
+identifier = 'dev.swiftcrossui.ForEachExample'
+product = 'ForEachExample'
+version = '0.1.0'

Examples/Package.swift

@@ -76,6 +76,10 @@ let package = Package(
         .executableTarget(
             name: "HoverExample",
             dependencies: exampleDependencies
-        )
+		),
+		.executableTarget(
+            name: "ForEachExample",
+            dependencies: exampleDependencies
+		)
     ]
 )

Examples/Sources/ForEachExample/ForEachApp.swift

@@ -0,0 +1,92 @@
+import DefaultBackend
+import Foundation
+import SwiftCrossUI
+
+#if canImport(SwiftBundlerRuntime)
+    import SwiftBundlerRuntime
+#endif
+
+@main
+@HotReloadable
+struct ForEachApp: App {
+    @State var items = (0..<20).map { Item("\($0)") }
+    @State var biggestValue = 19
+    @State var insertionPosition = 10
+
+    var body: some Scene {
+        WindowGroup("ForEach") {
+            #hotReloadable {
+                ScrollView {
+                    VStack {
+                        Button("Append") {
+                            biggestValue += 1
+                            items.append(.init("\(biggestValue)"))
+                        }
+
+                        #if !os(tvOS)
+                            Button(
+                                "Insert in front of current item at position \(insertionPosition)"
+                            ) {
+                                biggestValue += 1
+                                items.insert(.init("\(biggestValue)"), at: insertionPosition)
+                            }
+
+                            Slider($insertionPosition, minimum: 0, maximum: items.count - 1)
+                                .onChange(of: items.count) {
+                                    let upperLimit = max(items.count - 1, 0)
+                                    insertionPosition = min(insertionPosition, upperLimit)
+                                }
+                        #endif
+
+                        ForEach(Array(items.enumerated()), id: \.element.id) { (index, item) in
+                            ItemRow(
+                                item: item,
+                                isFirst: index == 0,
+                                isLast: index == items.count - 1
+                            ) {
+                                items.remove(at: index)
+                            } moveUp: {
+                                guard index != items.startIndex else { return }
+                                items.swapAt(index, index - 1)
+                            } moveDown: {
+                                guard index != items.endIndex else { return }
+                                items.swapAt(index, index + 1)
+                            }
+                        }
+                    }
+                    .padding(10)
+                }
+            }
+        }
+        .defaultSize(width: 400, height: 800)
+    }
+}
+
+struct ItemRow: View {
+    var item: Item
+    let isFirst: Bool
+    let isLast: Bool
+    var remove: () -> Void
+    var moveUp: () -> Void
+    var moveDown: () -> Void
+
+    var body: some View {
+        HStack {
+            Text(item.value)
+            Button("Delete") { remove() }
+            Button("⌃") { moveUp() }
+                .disabled(isFirst)
+            Button("⌄") { moveDown() }
+                .disabled(isLast)
+        }
+    }
+}
+
+struct Item: Identifiable {
+    let id = UUID()
+    var value: String
+
+    init(_ value: String) {
+        self.value = value
+    }
+}

Examples/Sources/GreetingGeneratorExample/GreetingGeneratorApp.swift

@@ -39,7 +39,7 @@ struct GreetingGeneratorApp: App {
                                 .padding(.top, 20)
 
                             ScrollView {
-                                ForEach(greetings.reversed()[1...]) { greeting in
+                                ForEach(greetings.reversed()[1...], id: \.self) { greeting in
                                     Text(greeting)
                                 }
                             }

Examples/Sources/StressTestExample/StressTestApp.swift

@@ -43,12 +43,11 @@ struct StressTestApp: App {
                             for _ in 0..<1000 {
                                 values.append(Self.options.randomElement()!)
                             }
-
                             self.values[tab!] = values
                         }
                         if let values = values[tab!] {
                             ScrollView {
-                                ForEach(values) { value in
+                                ForEach(values, id: \.self) { value in
                                     Text(value)
                                 }
                             }.frame(minWidth: 300)

Examples/Sources/WebViewExample/WebViewApp.swift

@@ -37,10 +37,14 @@ struct WebViewApp: App {
                     }
                     .padding()
 
-                    WebView($url)
-                        .onChange(of: url) {
-                            urlInput = url.absoluteString
-                        }
+                    #if !os(tvOS)
+                        WebView($url)
+                            .onChange(of: url) {
+                                urlInput = url.absoluteString
+                            }
+                    #else
+                        Text("WebView isn't supported on tvOS")
+                    #endif
                 }
             }
         }

Package.swift

@@ -122,6 +122,10 @@ let package = Package(
             url: "https://github.com/stackotter/swift-winui",
             revision: "1695ee3ea2b7a249f6504c7f1759e7ec7a38eb86"
         ),
+        .package(
+            url: "https://github.com/apple/swift-collections.git",
+            .upToNextMinor(from: "1.2.1")
+        ),
         .package(
             url: "https://github.com/stackotter/swift-benchmark",
             .upToNextMinor(from: "0.2.0")
@@ -150,6 +154,7 @@ let package = Package(
                 "HotReloadingMacrosPlugin",
                 .product(name: "ImageFormats", package: "swift-image-formats"),
                 .product(name: "Logging", package: "swift-log"),
+                .product(name: "OrderedCollections", package: "swift-collections"),
             ],
             exclude: [
                 "Builders/ViewBuilder.swift.gyb",

Sources/SwiftCrossUI/Builders/MenuItemsBuilder.swift

@@ -4,7 +4,7 @@ public struct MenuItemsBuilder {
     public static func buildBlock() -> [MenuItem] {
         []
     }
-    
+
     public static func buildPartialBlock(first: Button) -> [MenuItem] {
         [.button(first)]
     }
@@ -21,8 +21,8 @@ public struct MenuItemsBuilder {
         first.items
     }
 
-    public static func buildPartialBlock<Items: Collection>(
-        first: ForEach<Items, [MenuItem]>
+    public static func buildPartialBlock<Items: Collection, ID: Hashable>(
+        first: ForEach<Items, ID, [MenuItem]>
     ) -> [MenuItem] {
         first.elements.map(first.child).flatMap { $0 }
     }
@@ -55,9 +55,9 @@ public struct MenuItemsBuilder {
         accumulated + buildPartialBlock(first: next)
     }
 
-    public static func buildPartialBlock<Items: Collection>(
+    public static func buildPartialBlock<Items: Collection, ID: Hashable>(
         accumulated: [MenuItem],
-        next: ForEach<Items, [MenuItem]>
+        next: ForEach<Items, ID, [MenuItem]>
     ) -> [MenuItem] {
         accumulated + buildPartialBlock(first: next)
     }

Sources/SwiftCrossUI/Environment/Actions/OpenURLAction.swift

@@ -11,10 +11,12 @@ public struct OpenURLAction {
             do {
                 try backend.openExternalURL(url)
             } catch {
-                logger.warning("failed to open external url", metadata: [
-                    "url": "\(url)",
-                    "error": "\(error)",
-                ])
+                logger.warning(
+                    "failed to open external url",
+                    metadata: [
+                        "url": "\(url)",
+                        "error": "\(error)",
+                    ])
             }
         }
     }

Sources/SwiftCrossUI/Environment/Actions/RevealFileAction.swift

@@ -15,10 +15,12 @@ public struct RevealFileAction {
             do {
                 try backend.revealFile(file)
             } catch {
-                logger.warning("failed to reveal file", metadata: [
-                    "url": "\(file)",
-                    "error": "\(error)",
-                ])
+                logger.warning(
+                    "failed to reveal file",
+                    metadata: [
+                        "url": "\(file)",
+                        "error": "\(error)",
+                    ])
             }
         }
     }

Sources/SwiftCrossUI/Layout/LayoutSystem.swift

@@ -59,7 +59,8 @@ public enum LayoutSystem {
         var tag: String?
 
         public init(
-            computeLayout: @escaping @MainActor (ProposedViewSize, EnvironmentValues) ->
+            computeLayout:
+                @escaping @MainActor (ProposedViewSize, EnvironmentValues) ->
                 ViewLayoutResult,
             commit: @escaping @MainActor () -> ViewLayoutResult,
             tag: String? = nil

Sources/SwiftCrossUI/Views/Button.swift

@@ -21,8 +21,7 @@ public struct Button: Sendable {
     }
 }
 
-extension Button: View {
-}
+extension Button: View {}
 
 extension Button: ElementaryView {
     public func asWidget<Backend: AppBackend>(backend: Backend) -> Backend.Widget {

Sources/SwiftCrossUI/Views/EitherView.swift

@@ -59,7 +59,7 @@ extension EitherView: TypeSafeView {
         switch storage {
             case .a(let a):
                 switch children.node {
-                    case let .a(nodeA):
+                    case .a(let nodeA):
                         result = nodeA.computeLayout(
                             with: a,
                             proposedSize: proposedSize,
@@ -82,7 +82,7 @@ extension EitherView: TypeSafeView {
                 }
             case .b(let b):
                 switch children.node {
-                    case let .b(nodeB):
+                    case .b(let nodeB):
                         result = nodeB.computeLayout(
                             with: b,
                             proposedSize: proposedSize,