Update _EnvironmentKeyTransformModifier implementation

Package.resolved

@@ -6,7 +6,7 @@
       "location" : "https://github.com/OpenSwiftUIProject/OpenGraph",
       "state" : {
         "branch" : "main",
-        "revision" : "8baf226a2dd579d70febed94aa5bb23a04e1e56e"
+        "revision" : "ed01e7196afe56bf953f2f14b0b463208dda9c8d"
       }
     },
     {

Sources/OpenSwiftUI/Core/Attribute/AsyncAttribute.swift

@@ -0,0 +1,16 @@
+//
+//  AsyncAttribute.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+
+internal import OpenGraphShims
+
+protocol AsyncAttribute: _AttributeBody {}
+
+extension Attribute {
+    func syncMainIfReferences<V>(do body: (Value) -> V) -> V {
+        fatalError("TODO")
+    }
+}

Sources/OpenSwiftUI/Data/Environment/EnvironmentKeyTransformModifier.swift

@@ -3,9 +3,11 @@
 //  OpenSwiftUI
 //
 //  Audited for RELEASE_2021
-//  Status: WIP
+//  Status: Blocked by syncMainIfReferences
 //  ID: 1DBD4F024EFF0E73A70DB6DD05D5B548
 
+internal import OpenGraphShims
+
 @frozen
 public struct _EnvironmentKeyTransformModifier<Value>: PrimitiveViewModifier, _GraphInputsModifier {
     public var keyPath: WritableKeyPath<EnvironmentValues, Value>
@@ -17,12 +19,22 @@ public struct _EnvironmentKeyTransformModifier<Value>: PrimitiveViewModifier, _G
         self.transform = transform
     }
 
-    public static func _makeInputs(modifier: _GraphValue<_EnvironmentKeyTransformModifier<Value>>, inputs: inout _GraphInputs) {
-
+    public static func _makeInputs(modifier: _GraphValue<Self>, inputs: inout _GraphInputs) {
+        let childEnvironment = ChildEnvironment(
+            modifier: modifier.value,
+            environment: inputs.cachedEnvironment.wrappedValue.environment,
+            oldKeyPath: nil
+        )
+        let attribute = Attribute(childEnvironment)
+        let cachedEnvironment = CachedEnvironment(attribute)  
+        inputs.cachedEnvironment = MutableBox(cachedEnvironment)
+        inputs.changedDebugProperties.insert(.environment)
     }
 }
 
 extension View {
+    /// Transforms the environment value of the specified key path with the
+    /// given function.
     @inlinable
     public func transformEnvironment<V>(
         _ keyPath: WritableKeyPath<EnvironmentValues, V>,
@@ -35,6 +47,47 @@ extension View {
     }
 }
 
-private struct ChildEnvironment {
+private struct ChildEnvironment<Value>: StatefulRule, AsyncAttribute {
+    @Attribute
+    private var modifier: _EnvironmentKeyTransformModifier<Value>
+    private var _environment: Attribute<EnvironmentValues>
+    private var oldValue: Value?
+    private var oldKeyPath: WritableKeyPath<EnvironmentValues, Value>?
+
+    init(modifier: Attribute<_EnvironmentKeyTransformModifier<Value>>,
+         environment: Attribute<EnvironmentValues>,
+         oldValue: Value? = nil,
+         oldKeyPath: WritableKeyPath<EnvironmentValues, Value>?
+    ) {
+        _modifier = modifier
+        _environment = environment
+        self.oldValue = oldValue
+        self.oldKeyPath = oldKeyPath
+    }
 
+    var description: String {
+        "EnvironmentTransform: EnvironmentValues"
+    }
+
+    typealias Value = EnvironmentValues
+
+    mutating func updateValue() {
+        var (environment, environmentChanged) = _environment.changedValue()
+        let keyPath = modifier.keyPath
+        var newValue = environment[keyPath: keyPath]
+        _modifier.syncMainIfReferences { modifier in
+            modifier.transform(&newValue)
+        }
+        guard !environmentChanged,
+              let valueChanged = oldValue.map({ compareValues($0, newValue, mode: ._2) }), !valueChanged,
+              let keyPathChanged = oldKeyPath.map({ $0 == keyPath }), !keyPathChanged,
+              hasValue
+        else {
+            environment[keyPath: keyPath] = newValue
+            value = environment
+            oldValue = newValue
+            oldKeyPath = keyPath
+            return
+        }
+    }
 }

Sources/OpenSwiftUI/View/Core/Debug/TODO/ViewDebug.swift

@@ -56,16 +56,16 @@ extension _ViewDebug {
             self.rawValue = rawValue
         }
 
-        public static let type = Property(rawValue: 1 << Property.type.rawValue)
-        public static let value = Property(rawValue: 1 << Property.value.rawValue)
-        public static let transform = Property(rawValue: 1 << Property.transform.rawValue)
-        public static let position = Property(rawValue: 1 << Property.position.rawValue)
-        public static let size = Property(rawValue: 1 << Property.size.rawValue)
-        public static let environment = Property(rawValue: 1 << Property.environment.rawValue)
-        public static let phase = Property(rawValue: 1 << Property.phase.rawValue)
-        public static let layoutComputer = Property(rawValue: 1 << Property.layoutComputer.rawValue)
-        public static let displayList = Property(rawValue: 1 << Property.displayList.rawValue)
-        public static let all = Property(rawValue: 0xFFFF_FFFF)
+        public static let type = Properties(rawValue: 1 << Property.type.rawValue)
+        public static let value = Properties(rawValue: 1 << Property.value.rawValue)
+        public static let transform = Properties(rawValue: 1 << Property.transform.rawValue)
+        public static let position = Properties(rawValue: 1 << Property.position.rawValue)
+        public static let size = Properties(rawValue: 1 << Property.size.rawValue)
+        public static let environment = Properties(rawValue: 1 << Property.environment.rawValue)
+        public static let phase = Properties(rawValue: 1 << Property.phase.rawValue)
+        public static let layoutComputer = Properties(rawValue: 1 << Property.layoutComputer.rawValue)
+        public static let displayList = Properties(rawValue: 1 << Property.displayList.rawValue)
+        public static let all = Properties(rawValue: 0xFFFF_FFFF)
     }
 }