statelyai · Andarist · Mar 24, 2023 · Mar 13, 2023 · Mar 14, 2023 · Mar 17, 2023
diff --git a/.changeset/fresh-garlics-fry.md b/.changeset/fresh-garlics-fry.md
@@ -0,0 +1,22 @@
+---
+'xstate': major
+---
+
+Autoforwarding events is no longer supported and the `autoForward` property has been removed.
+
+Instead of autoforwarding, events should be explicitly sent to actors:
+
+```diff
+invoke: {
+  id: 'child',
+  src: 'someSrc',
+- autoForward: true
+},
+// ...
+on: {
+  // ...
++ EVENT_TO_FORWARD: {
++   actions: sendTo('child', (_, event) => event)
++ }
+}
+```
diff --git a/packages/core/src/actions/invoke.ts b/packages/core/src/actions/invoke.ts
@@ -85,7 +85,7 @@ export function invoke<
 
       resolvedInvokeAction.execute = (actorCtx) => {
         const interpreter = actorCtx.self as AnyInterpreter;
-        const { id, autoForward, ref } = resolvedInvokeAction.params;
+        const { id, ref } = resolvedInvokeAction.params;
         if (!ref) {
           if (!IS_PRODUCTION) {
             warn(
@@ -100,10 +100,6 @@ export function invoke<
             return;
           }
           try {
-            if (autoForward) {
-              interpreter._forwardTo.add(actorRef);
-            }
-
             actorRef.start?.();
           } catch (err) {
             interpreter.send(error(id, err));

diff --git a/packages/core/src/interpreter.ts b/packages/core/src/interpreter.ts
@@ -1,6 +1,5 @@
 import type {
   ActorContext,
-  AnyActorRef,
   AnyStateMachine,
   ActorBehavior,
   EventFromBehavior,
@@ -115,9 +114,6 @@ export class Interpreter<
    */
   public sessionId: string;
 
-  // TODO: remove
-  public _forwardTo: Set<AnyActorRef> = new Set();
-
   private _doneEvent?: DoneEvent;
 
   public src?: string;
@@ -303,8 +299,6 @@ export class Interpreter<
   }
 
   private _process(event: SCXML.Event<TEvent>) {
-    this.forward(event);
-
     try {
       const nextState = this.behavior.transition(
         this._state,
@@ -418,14 +412,6 @@ export class Interpreter<
     this.mailbox.enqueue(_event);
   }
 
-  // TODO: remove
-  private forward(event: SCXML.Event<TEvent>): void {
-    // The _forwardTo set will be empty for non-machine actors anyway
-    for (const child of this._forwardTo) {
-      child.send(event);
-    }
-  }
-
   // TODO: make private (and figure out a way to do this within the machine)
   public delaySend(
     sendAction: SendActionObject | RaiseActionObject<any, any, any>

diff --git a/packages/core/src/machine.schema.json b/packages/core/src/machine.schema.json
@@ -292,10 +292,6 @@
         },
         "src": {
           "type": "string"
-        },
-        "autoForward": {
-          "type": "boolean",
-          "default": false
         }
       },
       "required": ["type", "id", "src"],

diff --git a/packages/core/src/scxml.ts b/packages/core/src/scxml.ts
@@ -445,8 +445,7 @@ function toConfig(
 
       return {
         ...(element.attributes!.id && { id: element.attributes!.id as string }),
-        src: scxmlToMachine(content, options),
-        autoForward: element.attributes!.autoforward === 'true'
+        src: scxmlToMachine(content, options)
       };
     });
 

diff --git a/packages/core/src/types.ts b/packages/core/src/types.ts
@@ -396,12 +396,6 @@ export interface InvokeDefinition<
    * The source of the actor's behavior to be invoked
    */
   src: string;
-  /**
-   * If `true`, events sent to the parent service will be forwarded to the invoked service.
-   *
-   * Default: `false`
-   */
-  autoForward?: boolean;
 
   input?: Mapper<TContext, TEvent, any> | any;
   /**
@@ -530,12 +524,6 @@ export interface InvokeConfig<
    * The source of the machine to be invoked, or the machine itself.
    */
   src: string | ActorBehavior<any, any>; // TODO: fix types
-  /**
-   * If `true`, events sent to the parent service will be forwarded to the invoked service.
-   *
-   * Default: `false`
-   */
-  autoForward?: boolean;
 
   input?: Mapper<TContext, TEvent, any> | any;
   /**
@@ -1142,7 +1130,6 @@ export interface InvokeAction {
   type: ActionTypes.Invoke;
   src: string | ActorRef<any>;
   id: string;
-  autoForward?: boolean;
   exec?: undefined;
   meta: MetaObject | undefined;
 }
@@ -1160,7 +1147,6 @@ export interface InvokeActionObject extends BaseActionObject {
   params: {
     src: string | ActorRef<any>;
     id: string;
-    autoForward?: boolean;
     exec?: undefined;
     ref?: ActorRef<any>;
     meta: MetaObject | undefined;
@@ -1620,13 +1606,6 @@ export interface InterpreterOptions<_TActorBehavior extends AnyActorBehavior> {
    */
   devTools?: boolean | DevToolsAdapter; // TODO: add enhancer options
 
-  /**
-   * If `true`, events from the parent will be sent to this interpreter.
-   *
-   * Default: `false`
-   */
-  autoForward?: boolean;
-
   sync?: boolean;
 
   /**

diff --git a/packages/core/test/invoke.test.ts b/packages/core/test/invoke.test.ts
@@ -98,65 +98,7 @@ const fetcherMachine = createMachine({
 });
 
 describe('invoke', () => {
-  it('should start services (external machines)', (done) => {
-    const childMachine = createMachine({
-      id: 'child',
-      initial: 'init',
-      states: {
-        init: {
-          entry: [sendParent({ type: 'INC' }), sendParent({ type: 'INC' })]
-        }
-      }
-    });
-
-    const someParentMachine = createMachine<{ count: number }>(
-      {
-        id: 'parent',
-        context: { count: 0 },
-        initial: 'start',
-        states: {
-          start: {
-            invoke: {
-              src: 'child',
-              id: 'someService',
-              autoForward: true
-            },
-            always: {
-              target: 'stop',
-              guard: (ctx) => ctx.count === 2
-            },
-            on: {
-              INC: {
-                actions: assign({ count: (ctx) => ctx.count + 1 })
-              }
-            }
-          },
-          stop: {
-            type: 'final'
-          }
-        }
-      },
-      {
-        actors: {
-          child: childMachine
-        }
-      }
-    );
-
-    const actor = interpret(someParentMachine).onDone(() => {
-      // 1. The 'parent' machine will enter 'start' state
-      // 2. The 'child' service will be run with ID 'someService'
-      // 3. The 'child' machine will enter 'init' state
-      // 4. The 'entry' action will be executed, which sends 'INC' to 'parent' machine twice
-      // 5. The context will be updated to increment count to 2
-      expect(actor.getSnapshot().context.count).toEqual(2);
-      done();
-    });
-
-    actor.start();
-  });
-
-  it('should forward events to services if autoForward: true', () => {
+  it('child can immediately respond to the parent with multiple events', () => {
     const childMachine = createMachine({
       id: 'child',
       initial: 'init',
@@ -184,16 +126,17 @@ describe('invoke', () => {
           start: {
             invoke: {
               src: 'child',
-              id: 'someService',
-              autoForward: true
+              id: 'someService'
             },
             always: {
               target: 'stop',
               guard: (ctx) => ctx.count === -3
             },
             on: {
               DEC: { actions: assign({ count: (ctx) => ctx.count - 1 }) },
-              FORWARD_DEC: undefined
+              FORWARD_DEC: {
+                actions: sendTo('child', { type: 'FORWARD_DEC' })
+              }
             }
           },
           stop: {
@@ -216,7 +159,7 @@ describe('invoke', () => {
     service
       .onDone(() => {
         // 1. The 'parent' machine will not do anything (inert transition)
-        // 2. The 'FORWARD_DEC' event will be forwarded to the 'child' machine (autoForward: true)
+        // 2. The 'FORWARD_DEC' event will be "forwarded" to the 'child' machine
         // 3. On the 'child' machine, the 'FORWARD_DEC' event sends the 'DEC' action to the 'parent' thrice
         // 4. The context of the 'parent' machine will be updated from 2 to -1
 
@@ -227,102 +170,6 @@ describe('invoke', () => {
     service.send({ type: 'FORWARD_DEC' });
   });
 
-  it('should forward events to services if autoForward: true before processing them', (done) => {
-    const actual: string[] = [];
-
-    const childMachine = createMachine<{ count: number }>({
-      id: 'child',
-      context: { count: 0 },
-      initial: 'counting',
-      states: {
-        counting: {
-          on: {
-            INCREMENT: [
-              {
-                target: 'done',
-                guard: (ctx) => {
-                  actual.push('child got INCREMENT');
-                  return ctx.count >= 2;
-                },
-                actions: assign((ctx) => ({ count: ++ctx.count }))
-              },
-              {
-                target: undefined,
-                actions: assign((ctx) => ({ count: ++ctx.count }))
-              }
-            ]
-          }
-        },
-        done: {
-          type: 'final',
-          data: (ctx) => ({ countedTo: ctx.count })
-        }
-      },
-      on: {
-        START: {
-          actions: () => {
-            throw new Error('Should not receive START action here.');
-          }
-        }
-      }
-    });
-
-    const parentMachine = createMachine<{ countedTo: number }>({
-      id: 'parent',
-      context: { countedTo: 0 },
-      initial: 'idle',
-      states: {
-        idle: {
-          on: {
-            START: 'invokeChild'
-          }
-        },
-        invokeChild: {
-          invoke: {
-            src: childMachine,
-            autoForward: true,
-            onDone: {
-              target: 'done',
-              actions: assign((_ctx, event) => ({
-                countedTo: event.data.countedTo
-              }))
-            }
-          },
-          on: {
-            INCREMENT: {
-              actions: () => {
-                actual.push('parent got INCREMENT');
-              }
-            }
-          }
-        },
-        done: {
-          type: 'final'
-        }
-      }
-    });
-
-    const service = interpret(parentMachine)
-      .onDone(() => {
-        expect(service.getSnapshot().context).toEqual({ countedTo: 3 });
-        expect(actual).toEqual([
-          'child got INCREMENT',
-          'parent got INCREMENT',
-          'child got INCREMENT',
-          'parent got INCREMENT',
-          'child got INCREMENT',
-          'parent got INCREMENT'
-        ]);
-        done();
-      })
-      .start();
-
-    service.send({ type: 'START' });
-    service.send({ type: 'INCREMENT' });
-    service.send({ type: 'INCREMENT' });
-    service.send({ type: 'INCREMENT' });
-  });
-
   it('should start services (explicit machine, invoke = config)', (done) => {
     const childMachine = createMachine<{ userId: string | undefined }>({
       id: 'fetch',
@@ -507,8 +354,7 @@ describe('invoke', () => {
           start: {
             invoke: {
               src: 'child',
-              id: 'someService',
-              autoForward: true
+              id: 'someService'
             },
             on: {
               STOP: 'stop'

diff --git a/packages/core/test/json.test.ts b/packages/core/test/json.test.ts
@@ -19,10 +19,10 @@ describe('json', () => {
         number: 0,
         string: 'hello'
       },
-      invoke: [{ id: 'invokeId', src: 'invokeSrc', autoForward: true }],
+      invoke: [{ id: 'invokeId', src: 'invokeSrc' }],
       states: {
         testActions: {
-          invoke: [{ id: 'invokeId', src: 'invokeSrc', autoForward: true }],
+          invoke: [{ id: 'invokeId', src: 'invokeSrc' }],
           entry: [
             'stringActionType',
             {

diff --git a/packages/core/test/scxml.test.ts b/packages/core/test/scxml.test.ts
@@ -170,8 +170,8 @@ const testGroups: Record<string, string[]> = {
     // 'test225.txml', // unique invokeids generated at invoke time
     // 'test226.txml', // <invoke src="...">
     'test228.txml',
-    'test229.txml',
-    // 'test230.txml', // Manual test (TODO: check)
+    // 'test229.txml', // autoForward not supported in v5
+    // 'test230.txml', // autoForward not supported in v5
     'test232.txml',
     // 'test233.txml', // <finalize> not implemented yet
     // 'test234.txml', // <finalize> not implemented yet