Version

3.0.4

Reproduction link

https://codesandbox.io/s/awesome-christian-1kv3v?file=/src/App.vue

Steps to reproduce

1. Create a List component with slot.
2. Pass multiple items to List with list rendering.
3. Set value to items asynchronously.

What is expected?

Items rendered as expected

What is actually happening?

Items did't render and got an error TypeError: Cannot read property '0' of null

If items was intialized with one element at least, it works fine. And I also tried it with vue@3.0.3, everything is ok.

This bug might be caused by https://github.com/vuejs/vue-next/blame/v3.0.4/packages/runtime-core/src/renderer.ts#L1007, I'm also looking for its root cause.

This has been fixed in https://github.com/vuejs/vue-next/commit/c59897c7b0dbd82b5bbf3fbca945c0639ac37fb8. Not released