From 84c46c1ae95cea34355245a12ca2471eca996337 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Mon, 16 Oct 2023 20:40:57 +0200
Subject: [PATCH] Fixed an issue with not all actions of initial transitions
 being executed (#4357)

---
 .changeset/grumpy-shrimps-draw.md  |  5 +++++
 packages/core/src/StateMachine.ts  |  5 +++--
 packages/core/src/stateUtils.ts    | 27 ++++++++++++++++--------
 packages/core/test/actions.test.ts | 34 ++++++++++++++++++++++++++++++
 4 files changed, 60 insertions(+), 11 deletions(-)
 create mode 100644 .changeset/grumpy-shrimps-draw.md

diff --git a/.changeset/grumpy-shrimps-draw.md b/.changeset/grumpy-shrimps-draw.md
new file mode 100644
index 0000000000..2d5e264fe6
--- /dev/null
+++ b/.changeset/grumpy-shrimps-draw.md
@@ -0,0 +1,5 @@
+---
+'xstate': patch
+---
+
+Fixed an issue with not all actions of initial transitions resolving to the initial state of the machine itself being executed.
diff --git a/packages/core/src/StateMachine.ts b/packages/core/src/StateMachine.ts
index e181a78137..9dc73d7447 100644
--- a/packages/core/src/StateMachine.ts
+++ b/packages/core/src/StateMachine.ts
@@ -15,7 +15,8 @@ import {
   resolveActionsAndContext,
   resolveStateValue,
   transitionNode,
-  isAtomicStateNode
+  isAtomicStateNode,
+  getInitialStateNodes
 } from './stateUtils.ts';
 import type {
   AreAllImplementationsAssumedToBeProvided,
@@ -455,7 +456,7 @@ export class StateMachine<
     const nextState = microstep(
       [
         {
-          target: [...preInitialState.configuration].filter(isAtomicStateNode),
+          target: [...getInitialStateNodes(this.root)],
           source: this.root,
           reenter: true,
           actions: [],
diff --git a/packages/core/src/stateUtils.ts b/packages/core/src/stateUtils.ts
index cb9fea5d22..11d25d7991 100644
--- a/packages/core/src/stateUtils.ts
+++ b/packages/core/src/stateUtils.ts
@@ -126,7 +126,9 @@ export function getConfiguration(
   for (const s of configuration) {
     // if previously active, add existing child nodes
     if (s.type === 'compound' && (!adjList.get(s) || !adjList.get(s)!.length)) {
-      getInitialStateNodes(s).forEach((sn) => configurationSet.add(sn));
+      getInitialStateNodesWithTheirAncestors(s).forEach((sn) =>
+        configurationSet.add(sn)
+      );
     } else {
       if (s.type === 'parallel') {
         for (const child of getChildren(s)) {
@@ -135,7 +137,8 @@ export function getConfiguration(
           }
 
           if (!configurationSet.has(child)) {
-            for (const initialStateNode of getInitialStateNodes(child)) {
+            const initialStates = getInitialStateNodesWithTheirAncestors(child);
+            for (const initialStateNode of initialStates) {
               configurationSet.add(initialStateNode);
             }
           }
@@ -594,9 +597,19 @@ function isHistoryNode(
   return stateNode.type === 'history';
 }
 
-export function getInitialStateNodes(
+export function getInitialStateNodesWithTheirAncestors(
   stateNode: AnyStateNode
-): Array<AnyStateNode> {
+) {
+  const states = getInitialStateNodes(stateNode);
+  for (const initialState of states) {
+    for (const ancestor of getProperAncestors(initialState, stateNode)) {
+      states.add(ancestor);
+    }
+  }
+  return states;
+}
+
+export function getInitialStateNodes(stateNode: AnyStateNode) {
   const set = new Set<AnyStateNode>();
 
   function iter(descStateNode: AnyStateNode): void {
@@ -606,10 +619,6 @@ export function getInitialStateNodes(
     set.add(descStateNode);
     if (descStateNode.type === 'compound') {
       for (const targetStateNode of descStateNode.initial.target) {
-        for (const a of getProperAncestors(targetStateNode, stateNode)) {
-          set.add(a);
-        }
-
         iter(targetStateNode);
       }
     } else if (descStateNode.type === 'parallel') {
@@ -621,7 +630,7 @@ export function getInitialStateNodes(
 
   iter(stateNode);
 
-  return [...set];
+  return set;
 }
 /**
  * Returns the child state node from its relative `stateKey`, or throws.
diff --git a/packages/core/test/actions.test.ts b/packages/core/test/actions.test.ts
index 8e8b55e3db..9b9a1a6a25 100644
--- a/packages/core/test/actions.test.ts
+++ b/packages/core/test/actions.test.ts
@@ -2170,6 +2170,40 @@ describe('initial actions', () => {
       ]
     `);
   });
+
+  it('should execute actions of all initial transitions resolving to the initial state value', () => {
+    const spy = jest.fn();
+    const machine = createMachine({
+      initial: {
+        target: 'a',
+        actions: () => spy('root')
+      },
+      states: {
+        a: {
+          initial: {
+            target: 'a1',
+            actions: () => spy('inner')
+          },
+          states: {
+            a1: {}
+          }
+        }
+      }
+    });
+
+    createActor(machine).start();
+
+    expect(spy.mock.calls).toMatchInlineSnapshot(`
+      [
+        [
+          "root",
+        ],
+        [
+          "inner",
+        ],
+      ]
+    `);
+  });
 });
 
 describe('actions on invalid transition', () => {