When app.unmount() is called immediately after app.mount(), an error will be reported, as follows:

[withoutmeat]

Version

6.0.0-beta.12

Browser and OS info

Chrome 90 / Mac 10.15.7

Steps to reproduce

main.ts

import { createApp } from "vue";
import App from "./App.vue";

const vm = createApp(App);
vm.mount("#app");
vm.unmount();

What is expected?

no error.

What is actually happening?

throw error: TypeError: Cannot set property 'VUE_DEVTOOLS_UID' of null at registerAppJob (backend.js:743)

[Akryum]

Will display a warning instead of throwing