From bd89ce53a9de417a9372630bb5d433a40acc1a53 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Mon, 15 Aug 2022 15:37:13 +0800
Subject: [PATCH] fix: ensure render watcher of manually created instance is
 correctly tracked in owner scope

fix #12701
---
 src/core/instance/lifecycle.ts | 2 ++
 src/core/observer/watcher.ts   | 6 ++----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/core/instance/lifecycle.ts b/src/core/instance/lifecycle.ts
index df70b7113..fec330ad5 100644
--- a/src/core/instance/lifecycle.ts
+++ b/src/core/instance/lifecycle.ts
@@ -209,6 +209,7 @@ export function mountComponent(
   // we set this to vm._watcher inside the watcher's constructor
   // since the watcher's initial patch may call $forceUpdate (e.g. inside child
   // component's mounted hook), which relies on vm._watcher being already defined
+  vm._scope.on()
   new Watcher(
     vm,
     updateComponent,
@@ -216,6 +217,7 @@ export function mountComponent(
     watcherOptions,
     true /* isRenderWatcher */
   )
+  vm._scope.off()
   hydrating = false
 
   // flush buffer for flush: "pre" watchers queued in setup()
diff --git a/src/core/observer/watcher.ts b/src/core/observer/watcher.ts
index b1f491acb..00bf19b91 100644
--- a/src/core/observer/watcher.ts
+++ b/src/core/observer/watcher.ts
@@ -72,10 +72,8 @@ export default class Watcher implements DepTarget {
     isRenderWatcher?: boolean
   ) {
     recordEffectScope(this, activeEffectScope || (vm ? vm._scope : undefined))
-    if ((this.vm = vm)) {
-      if (isRenderWatcher) {
-        vm._watcher = this
-      }
+    if ((this.vm = vm) && isRenderWatcher) {
+      vm._watcher = this
     }
     // options
     if (options) {