GH-17 fix issue with simultaneous accesses to viewModel property

Author: rickclephas

KMMViewModelCore/KMMViewModel.swift

@@ -9,7 +9,7 @@ import Combine
 import KMMViewModelCoreObjC
 
 /// A Kotlin Multiplatform Mobile ViewModel.
-public protocol KMMViewModel: ObservableObject where ObjectWillChangePublisher == ObservableObjectPublisher {
+public protocol KMMViewModel: AnyObject, ObservableObject where ObjectWillChangePublisher == ObservableObjectPublisher {
     /// The `ViewModelScope` of this `KMMViewModel`.
     var viewModelScope: ViewModelScope { get }
 }

KMMViewModelCore/ObservableViewModel.swift

@@ -21,20 +21,11 @@ public final class ObservableViewModel<ViewModel: KMMViewModel>: ObservableObjec
 
     public let objectWillChange: ObservableViewModelPublisher
 
-    private var _viewModel: ViewModel
-    public var viewModel: ViewModel { _viewModel }
+    public let viewModel: ViewModel
 
     internal init(_ viewModel: ViewModel) {
         objectWillChange = ObservableViewModelPublisher(viewModel.viewModelScope, viewModel.objectWillChange)
-        self._viewModel = viewModel
-    }
-    
-    public func get<T>(_ keyPath: KeyPath<ViewModel, T>) -> T {
-        _viewModel[keyPath: keyPath]
-    }
-    
-    public func set<T>(_ keyPath: WritableKeyPath<ViewModel, T>, to newValue: T) {
-        _viewModel[keyPath: keyPath] = newValue
+        self.viewModel = viewModel
     }
 }
 

KMMViewModelSwiftUI/ObservableViewModelProjection.swift

@@ -22,9 +22,10 @@ public extension ObservableViewModel {
 
         public subscript<T>(dynamicMember keyPath: WritableKeyPath<ViewModel, T>) -> Binding<T> {
             Binding {
-                observableObject.get(keyPath)
+                observableObject.viewModel[keyPath: keyPath]
             } set: { value in
-                observableObject.set(keyPath, to: value)
+                var viewModel = observableObject.viewModel
+                viewModel[keyPath: keyPath] = value
             }
         }
     }