From 7c1e665215adf22bf2d8fff776a0a58e7dfee0f9 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Tue, 4 May 2021 11:34:15 -0400
Subject: [PATCH] wip: root instance $destroy before $mount

---
 packages/runtime-core/src/compat/global.ts | 28 +++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/packages/runtime-core/src/compat/global.ts b/packages/runtime-core/src/compat/global.ts
index 4cf57743a..0949d5971 100644
--- a/packages/runtime-core/src/compat/global.ts
+++ b/packages/runtime-core/src/compat/global.ts
@@ -1,6 +1,7 @@
 import {
   isReactive,
   reactive,
+  stop,
   track,
   TrackOpTypes,
   trigger,
@@ -13,7 +14,8 @@ import {
   EMPTY_OBJ,
   isArray,
   isObject,
-  isString
+  isString,
+  invokeArrayFns
 } from '@vue/shared'
 import { warn } from '../warning'
 import { cloneVNode, createVNode } from '../vnode'
@@ -467,8 +469,28 @@ export function installCompatMount(
           devtoolsUnmountApp(app)
         }
         delete app._container.__vue_app__
-      } else if (__DEV__) {
-        warn(`Cannot unmount an app that is not mounted.`)
+      } else {
+        const { bum, effects, um } = instance
+        // beforeDestroy hooks
+        if (bum) {
+          invokeArrayFns(bum)
+        }
+        if (isCompatEnabled(DeprecationTypes.INSTANCE_EVENT_HOOKS, instance)) {
+          instance.emit('hook:beforeDestroy')
+        }
+        // stop effects
+        if (effects) {
+          for (let i = 0; i < effects.length; i++) {
+            stop(effects[i])
+          }
+        }
+        // unmounted hook
+        if (um) {
+          invokeArrayFns(um)
+        }
+        if (isCompatEnabled(DeprecationTypes.INSTANCE_EVENT_HOOKS, instance)) {
+          instance.emit('hook:destroyed')
+        }
       }
     }