Isolate cancellation in root stores.

Sources/ComposableArchitecture/Internal/NavigationID.swift

@@ -38,6 +38,8 @@ struct NavigationID: Hashable, @unchecked Sendable {
   private let identifier: AnyHashable?
   private let tag: UInt32?
 
+
+
   enum Kind: Hashable {
     case casePath(root: Any.Type, value: Any.Type)
     case keyPath(AnyKeyPath)
@@ -111,6 +113,12 @@ struct NavigationID: Hashable, @unchecked Sendable {
     }
   }
 
+  init(kind: Kind, identifier: AnyHashable?, tag: UInt32?) {
+    self.kind = kind
+    self.identifier = identifier
+    self.tag = tag
+  }
+
   static func == (lhs: Self, rhs: Self) -> Bool {
     lhs.kind == rhs.kind
       && lhs.identifier == rhs.identifier

Sources/ComposableArchitecture/Store.swift

@@ -174,7 +174,17 @@ public final class Store<State, Action> {
     @ReducerBuilder<State, Action> reducer: () -> R,
     withDependencies prepareDependencies: ((inout DependencyValues) -> Void)? = nil
   ) {
-    let (initialState, reducer, dependencies) = withDependencies(prepareDependencies ?? { _ in }) {
+    let prepDeps: (inout DependencyValues) -> Void = {
+      $0.navigationIDPath = NavigationIDPath(path: [
+        NavigationID(
+          kind: .keyPath(\State.self),
+          identifier: UUID(),
+          tag: nil
+        )
+      ])
+      prepareDependencies?(&$0)
+    }
+    let (initialState, reducer, dependencies) = withDependencies(prepDeps) {
       @Dependency(\.self) var dependencies
       return (initialState(), reducer(), dependencies)
     }
@@ -329,7 +339,8 @@ public final class Store<State, Action> {
   }
 
   @available(
-    *, deprecated,
+    *,
+    deprecated,
     message:
       "Pass 'state' a key path to child state and 'action' a case key path to child action, instead. For more information see the following migration guide: https://pointfreeco.github.io/swift-composable-architecture/main/documentation/composablearchitecture/migratingto1.5#Store-scoping-with-key-paths"
   )

Tests/ComposableArchitectureTests/StoreTests.swift

@@ -1213,6 +1213,58 @@ final class StoreTests: BaseTCATestCase {
       }
     }
   }
+
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  @MainActor func testRootStoreCancellationIsolation() async throws {
+    let clock = TestClock()
+    let store1 = Store(initialState: RootStoreCancellationIsolation.State()) {
+      RootStoreCancellationIsolation()
+    } withDependencies: {
+      $0.continuousClock = clock
+    }
+    let store2 = Store(initialState: RootStoreCancellationIsolation.State()) {
+      RootStoreCancellationIsolation()
+    } withDependencies: {
+      $0.continuousClock = clock
+    }
+    store1.send(.tap)
+    store2.send(.tap)
+    try await Task.sleep(nanoseconds: 100_000_000)
+    store2.send(.cancelButtonTapped)
+    await clock.run()
+    XCTAssertEqual(store1.count, 42)
+    XCTAssertEqual(store2.count, 0)
+  }
+  @available(iOS 16, macOS 13, tvOS 16, watchOS 9, *)
+  @Reducer struct RootStoreCancellationIsolation {
+    @ObservableState struct State: Equatable {
+      var count = 0
+    }
+    enum Action {
+      case cancelButtonTapped
+      case response(Int)
+      case tap
+    }
+    @Dependency(\.continuousClock) var clock
+    enum CancelID { case effect }
+    var body: some ReducerOf<Self> {
+      Reduce<State, Action> { state, action in
+        switch action {
+        case .cancelButtonTapped:
+          return .cancel(id: CancelID.effect)
+        case .response(let value):
+          state.count = value
+          return .none
+        case .tap:
+          return .run { send in
+            try await clock.sleep(for: .seconds(1))
+            await send(.response(42))
+          }
+          .cancellable(id: CancelID.effect)
+        }
+      }
+    }
+  }
 }
 
 #if canImport(Testing)