Fix SwiftUI synchronous fetch definitions not rendering

Example/iOS-Example/Model+Fetchable.swift

@@ -20,9 +20,7 @@ extension FetchableObjectProtocol where Self: Model {
 
         return FetchDefinition<Self>(
             request: { completion in
-                DispatchQueue.main.async {
-                    completion(fetchAll())
-                }
+                completion(fetchAll())
             },
             objectCreationToken: ModelCreationToken<Self>(),
             dataResetTokens: dataResetTokens

Example/iOS-Example/Model.swift

@@ -116,11 +116,11 @@ extension Model: FetchableObjectProtocol {
     }
 
     func observeIsDeletedChanges(_ handler: @escaping @MainActor () -> Void) -> InvalidatableToken {
-        self.observe(\.isDeleted, options: [.old, .new]) { @MainActor(unsafe) object, change in
+        self.observe(\.isDeleted, options: [.old, .new]) { object, change in
             guard let old = change.oldValue, let new = change.newValue, old != new else {
                 return
             }
-            handler()
+            unsafeHandler(for: handler)
         }
     }
 
@@ -133,6 +133,13 @@ extension Model: FetchableObjectProtocol {
     }
 }
 
+@MainActor(unsafe)
+private func unsafeHandler(for handler: @MainActor () -> Void) {
+    assert(Thread.isMainThread)
+    // This is a dumb wrapper, but I can't otherwise have a "clean" compile
+    handler()
+}
+
 // MARK: - Private Helpers
 
 private extension Model {

Example/iOS-Example/SwiftUIView.swift

@@ -33,24 +33,22 @@ struct SwiftUIView: View {
             .transition(.slide)
             .navigationBarTitle("SwiftUI Example", displayMode: .inline)
             .navigationBarItems(
-                leading:
-                    Button {
-                        Model.reset()
-                    } label: {
-                        Image(systemName: "trash")
-                    },
-                trailing:
-                    Button {
-                        try? Model().save()
-                    } label: {
-                        Image(systemName: "plus")
-                    }
+                leading: Button {
+                    Model.reset()
+                } label: {
+                    Image(systemName: "trash")
+                },
+                trailing: Button {
+                    try? Model().save()
+                } label: {
+                    Image(systemName: "plus")
+                }
             )
         }
     }
 }
 
-// Mark: List Row
+// MARK: List Row
 extension SwiftUIView {
     @ViewBuilder
     func row(for model: Model) -> some View {

Example/iOS-Example/ViewController.swift

@@ -131,7 +131,7 @@ private extension ViewController {
     func addItem(_ sender: Any) {
         try? Model().save()
     }
-    
+
     @objc
     func showSwiftUI(_ sender: Any) {
         present(UIHostingController(rootView: SwiftUIView()), animated: true)

FetchRequests/Sources/SwiftUI/FetchableRequest.swift

@@ -100,8 +100,11 @@ public struct FetchableRequest<FetchedObject: FetchableObject>: DynamicProperty
             return
         }
 
+        var isSynchronous = true
+
         defer {
             fetchController.performFetch()
+            isSynchronous = false
         }
 
         let controller = fetchController
@@ -112,12 +115,22 @@ public struct FetchableRequest<FetchedObject: FetchableObject>: DynamicProperty
             guard let controller else {
                 return
             }
-            withAnimation(animation) {
-                let newVersion = binding.wrappedValue.version + 1
-                binding.wrappedValue = FetchableResults(
-                    contents: controller.fetchedObjects,
-                    version: newVersion
-                )
+            let change: () -> Void = {
+                withAnimation(animation) {
+                    let newVersion = binding.wrappedValue.version + 1
+                    binding.wrappedValue = FetchableResults(
+                        contents: controller.fetchedObjects,
+                        version: newVersion
+                    )
+                }
+            }
+
+            if isSynchronous {
+                DispatchQueue.main.async {
+                    change()
+                }
+            } else {
+                change()
             }
         }
     }

FetchRequests/Tests/Controllers/CollapsibleSectionsFetchedResultsControllerTestCase.swift

@@ -145,11 +145,11 @@ extension CollapsibleSectionsFetchedResultsControllerTestCase {
         let originalObjects = createTestObjects(count: 20, inSectionsOfLength: 10)
         try performFetch(originalObjects)
 
-        XCTAssert(controller.sections[0].allObjects.count == 10)
+        XCTAssertEqual(controller.sections[0].allObjects.count, 10)
         XCTAssertEqual(controller.sections[0].displayableObjects.count, maxNumberOfItems)
 
-        XCTAssert(controller.sections[1].allObjects.count == 10)
-        XCTAssert(controller.sections[1].displayableObjects.count == controller.sections[1].allObjects.count)
+        XCTAssertEqual(controller.sections[1].allObjects.count, 10)
+        XCTAssertEqual(controller.sections[1].displayableObjects.count, controller.sections[1].allObjects.count)
 
         controller.update(section: controller.sections[0], maximumNumberOfItemsToDisplay: 6)
         XCTAssertEqual(controller.sections[0].displayableObjects.count, 6)

FetchRequests/Tests/Models/FetchableObjectProtocolTestCase.swift

@@ -14,10 +14,10 @@ class FetchableObjectProtocolTestCase: XCTestCase {
         let data: TestObject.RawData = ["id": "1", "test": 2]
         var newData: TestObject.RawData = ["id": "1", "test": 3]
 
-        XCTAssertFalse(data == newData)
+        XCTAssertNotEqual(data, newData)
 
         newData.test = 2
 
-        XCTAssertTrue(data == newData)
+        XCTAssertEqual(data, newData)
     }
 }

FetchRequests/Tests/Models/JSONTestCase.swift

@@ -418,7 +418,7 @@ extension JSONTestCase {
     func testNonJsonNSObjectForBoxedJSON() {
         let set = NSSet(objects: "1", "2")
         let boxed = BoxedJSON(__object: set)
-        XCTAssertTrue(boxed == nil)
+        XCTAssertNil(boxed)
     }
 
     func testJsonNSObjectForBoxedJSON() {