fix cancellation id prefix.

Author: mbrandonw

Sources/ComposableArchitecture/Internal/NavigationID.swift

@@ -23,14 +23,18 @@ struct NavigationIDPath: Hashable, Sendable {
 
   var prefixes: [NavigationIDPath] {
     (0...self.path.count).map { index in
-      NavigationIDPath(path: Array(self.path.dropFirst(index)))
+      NavigationIDPath(path: Array(self.path.prefix(self.path.count - index)))
     }
   }
 
   func appending(_ element: NavigationID) -> Self {
     .init(path: self.path + [element])
   }
 
+  mutating func append(_ element: NavigationID) {
+    self.path.append(element)
+  }
+
   public var id: Self { self }
 }
 

Sources/ComposableArchitecture/Store.swift

@@ -177,7 +177,7 @@ public final class Store<State, Action> {
     let (initialState, reducer, dependencies) = withDependencies(prepareDependencies ?? { _ in }) {
       @Dependency(\.self) var dependencies
       var updatedDependencies = dependencies
-      updatedDependencies.navigationIDPath = NavigationIDPath(path: [NavigationID()])
+      updatedDependencies.navigationIDPath.append(NavigationID())
       return (initialState(), reducer(), updatedDependencies)
     }
     self.init(

Sources/ComposableArchitecture/TestStore.swift

@@ -541,7 +541,7 @@ public final class TestStore<State: Equatable, Action> {
     let reducer = Dependencies.withDependencies {
       prepareDependencies(&$0)
       sharedChangeTracker.track(&$0)
-      $0.navigationIDPath = NavigationIDPath(path: [NavigationID()])
+      $0.navigationIDPath.append(NavigationID())
     } operation: {
       TestReducer(Reduce(reducer()), initialState: initialState())
     }

Tests/ComposableArchitectureTests/Reducers/PresentationReducerTests.swift

@@ -1109,7 +1109,7 @@ final class PresentationReducerTests: BaseTCATestCase {
     await presentationTask.cancel()
   }
 
-  func testNavigation_cancelID_parentCancellation() async {
+  func testNavigation_cancelID_parentCancellation() async throws {
     struct Grandchild: Reducer {
       struct State: Equatable {}
       enum Action: Equatable {
@@ -1193,17 +1193,15 @@ final class PresentationReducerTests: BaseTCATestCase {
     let store = await TestStore(initialState: Parent.State()) {
       Parent()
     }
-    let childPresentationTask = await store.send(.presentChild) {
+    await store.send(.presentChild) {
       $0.child = Child.State()
     }
-    let grandchildPresentationTask = await store.send(.child(.presented(.presentGrandchild))) {
+    await store.send(.child(.presented(.presentGrandchild))) {
       $0.child?.grandchild = Grandchild.State()
     }
     await store.send(.child(.presented(.startButtonTapped)))
     await store.send(.child(.presented(.grandchild(.presented(.startButtonTapped)))))
     await store.send(.stopButtonTapped)
-    await grandchildPresentationTask.cancel()
-    await childPresentationTask.cancel()
   }
 
   func testNavigation_cancelID_parentCancelTwoChildren() async {

Tests/ComposableArchitectureTests/StoreTests.swift

@@ -1251,7 +1251,6 @@ final class StoreTests: BaseTCATestCase {
     }
     await store1.send(.tap)
     await store2.send(.tap)
-    try await Task.sleep(nanoseconds: 100_000_000)
     await store2.send(.cancelButtonTapped)
     await clock.run()
     await store1.receive(\.response) {