Does not work with createSSRApp

[danelowe]

Version

6.0.0-beta.7

Browser and OS info

Firefox 86.0 / macOS 11.1

Steps to reproduce

Download https://github.com/vitejs/vite.git and cd to packages/playground/ssr-vue

run npm i vite, then npm run dev. Open localhost:3000 in browser and try to use vue-devtools.

What is expected?

Vue devtools shows an app running on localhost:3000

What is actually happening?

Vue devtools shows 'No App' in the app selector.

Errors in console:

Uncaught (in promise) TypeError: record.rootInstance is null
    registerAppJob moz-extension://a954018d-dafd-ae48-aeca-7157f39e6cca/build/backend.js:1437
    registerApp moz-extension://a954018d-dafd-ae48-aeca-7157f39e6cca/build/backend.js:1403
    run moz-extension://a954018d-dafd-ae48-aeca-7157f39e6cca/build/backend.js:4373
    queue moz-extension://a954018d-dafd-ae48-aeca-7157f39e6cca/build/backend.js:4379

---

If you open up main.js in the example project and change the code to use createApp, devtools will work.

import App from './App.vue'
import { createApp as _createApp } from 'vue'
import { createRouter } from './router'

// SSR requires a fresh app instance per request, therefore we export a function
// that creates a fresh app instance. If using Vuex, we'd also be creating a
// fresh store here.
export function createApp() {
  const app = _createApp(App)
  const router = createRouter()
  app.use(router)
  return { app, router }
}

There are mentions of this at #1289, but that issue seemed to have been closed due to a flood of comments from people using Vue 2.

This issue is also present when using chrome, and when using standalone vue-devtools app.

[danelowe]

Based on #1289 (comment), I added a workaround.

const instance = app.mount(rootContainer, true)
app._container._vnode = instance.$.vnode