From a62da807c300a1e09443689ead7f8c01386bef30 Mon Sep 17 00:00:00 2001
From: daiwei <daiwei521@126.com>
Date: Mon, 13 Feb 2023 17:45:37 +0800
Subject: [PATCH] chore: rebase

---
 packages/reactivity/src/effectScope.ts        |  8 ++++--
 .../runtime-core/__tests__/apiWatch.spec.ts   | 27 +++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/packages/reactivity/src/effectScope.ts b/packages/reactivity/src/effectScope.ts
index c644d03fae6..3ded91da878 100644
--- a/packages/reactivity/src/effectScope.ts
+++ b/packages/reactivity/src/effectScope.ts
@@ -81,8 +81,12 @@ export class EffectScope {
   stop(fromParent?: boolean) {
     if (this._active) {
       let i, l
-      for (i = 0, l = this.effects.length; i < l; i++) {
-        this.effects[i].stop()
+      // #5783
+      // effects will be changed when a watcher stoped.
+      // so we need to copy it for iteration.
+      const effectsToStop = this.effects.slice()
+      for (i = 0, l = effectsToStop.length; i < l; i++) {
+        effectsToStop[i].stop()
       }
       for (i = 0, l = this.cleanups.length; i < l; i++) {
         this.cleanups[i]()
diff --git a/packages/runtime-core/__tests__/apiWatch.spec.ts b/packages/runtime-core/__tests__/apiWatch.spec.ts
index 1b9f500da3c..c0dc1f4d300 100644
--- a/packages/runtime-core/__tests__/apiWatch.spec.ts
+++ b/packages/runtime-core/__tests__/apiWatch.spec.ts
@@ -1126,6 +1126,33 @@ describe('api: watch', () => {
     expect(spy).toHaveBeenCalledTimes(2)
   })
 
+  test('handle nested watcher stop properly', () => {
+    let instance: ComponentInternalInstance
+    const Comp = {
+      setup() {
+        instance = getCurrentInstance()!
+        watch(
+          () => 1,
+          (val, oldVal, onCleanup) => {
+            const stop = watch(
+              () => 2,
+              () => {}
+            )
+            onCleanup(stop)
+          },
+          { immediate: true }
+        )
+        return () => ''
+      }
+    }
+    const root = nodeOps.createElement('div')
+    createApp(Comp).mount(root)
+    expect(instance!.scope.effects.length).toBe(3)
+
+    instance!.scope.stop()
+    expect(instance!.scope.effects[0].active).toBe(false)
+  })
+
   it('watching sources: ref<any[]>', async () => {
     const foo = ref([1])
     const spy = vi.fn()