Update State example (#192)

* Fix Transaction.current crash issue

* Add StateTests case

Author: Kyle-Ye

Example/HostingExample/ViewController.swift

@@ -47,28 +47,29 @@ struct ContentView: View {
     @State private var first = true
 
     var body: some View {
-        if first {
-            Color.red
-                .onAppear {
-                    print("Red appear")
-                    DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
-                        first.toggle()
-                    }
+//        if first {
+        Color(uiColor: first ? .red : .blue)
+            .onAppear {
+                print("View appear")
+                DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+                    first.toggle()
                 }
-                .onDisappear {
-                    print("Red disappear")
-                }
-        } else {
-            Color.blue
-                .onAppear {
-                    print("Blue appear")
-                    DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
-                        first.toggle()
-                    }
-                }
-                .onDisappear {
-                    print("Blue disappear")
-                }
-        }
+            }
+            // .id(first)
+//                .onDisappear {
+//                    print("Red disappear")
+//                }
+//        } else {
+//            Color.blue
+//                .onAppear {
+//                    print("Blue appear")
+//                    DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+//                        first.toggle()
+//                    }
+//                }
+//                .onDisappear {
+//                    print("Blue disappear")
+//                }
+//        }
     }
 }

Sources/OpenSwiftUICore/Data/Transaction/Transaction.swift

@@ -91,8 +91,8 @@ public struct Transaction {
     }
 
     package static var current: Transaction {
-        if let data = _threadTransactionData() as? AnyObject {
-            Transaction(plist: PropertyList(data: data))
+        if let data = _threadTransactionData() {
+            Transaction(plist: PropertyList(data: data as? AnyObject))
         } else {
             Transaction()
         }

Sources/OpenSwiftUICore/Graph/GraphHost.swift

@@ -371,7 +371,7 @@ extension GraphHost {
         style: _GraphMutation_Style = .deferred,
         mayDeferUpdate: Bool = true
     ) where T: GraphMutation {
-        preconditionFailure("TODO")
+        // preconditionFailure("TODO")
     }
 
     package final func asyncTransaction(

Tests/OpenSwiftUICompatibilityTests/SwiftUICore/Data/Environment/EnvironmentValuesTest.swift renamed to Tests/OpenSwiftUICompatibilityTests/SwiftUICore/Data/Environment/EnvironmentValuesTests.swift

@@ -1,13 +1,10 @@
 //
-//  EnvironmentValuesTest.swift
-//
-//
-//  Created by Kyle on 2023/11/21.
-//
+//  EnvironmentValuesTests.swift
+//  OpenSwiftUICompatibilityTests
 
 import Testing
 
-struct EnvironmentValuesTest {
+struct EnvironmentValuesTests {
     struct BoolKey: EnvironmentKey {
         fileprivate static var name: String { "EnvironmentPropertyKey<BoolKey>" }
 

Tests/OpenSwiftUICompatibilityTests/SwiftUICore/Data/State/StateTests.swift

@@ -0,0 +1,38 @@
+//
+//  StateTests.swift
+//  OpenSwiftUICompatibilityTests
+
+import Testing
+
+#if canImport(Darwin)
+struct StateTests {
+    @Test
+    func appear() async throws {
+        struct ContentView: View {
+            var confirmation: Confirmation
+
+            @State private var toggle = false
+            
+            var body: some View {
+                AnyView(EmptyView())
+                    .onAppear {
+                        toggle.toggle()
+                        if toggle {
+                            confirmation()
+                        }
+                    }
+            }
+        }
+
+        #if os(iOS)
+        await confirmation { @MainActor confirmation in
+            let vc = UIHostingController(rootView: ContentView(confirmation: confirmation))
+            vc.triggerLayout()
+            workaroundIssue87(vc)
+        }
+        #endif
+    }
+    
+    // TODO: Add disappear support and test case
+}
+#endif

Tests/OpenSwiftUICompatibilityTests/SwiftUICore/Modifier/ViewModifier/AppearanceActionModifierTests.swift

@@ -8,12 +8,6 @@ import Testing
 struct AppearanceActionModifierTests {
     @Test
     func appear() async throws {
-        guard #unavailable(iOS 18) else {
-            withKnownIssue {
-                Issue.record("Known crash issue on iOS 18")
-            }
-            return
-        }
         struct ContentView: View {
             var confirmation: Confirmation