v-model update being bubbled up on root components

[Kurira]

Version

3.0.0-rc.4

Reproduction link

https://codesandbox.io/s/hungry-mendeleev-dfiy9

Steps to reproduce

1. Open https://codesandbox.io/s/hungry-mendeleev-dfiy9
2. Press count button

What is expected?

It should correctly increase count value to 3 and so on. Works on vue2.

What is actually happening?

Now it sets the whole wrapper object to that number, instead of the property.

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Wrapping hello component in a div works as a workaround.

[posva]

In your example your Hello component is using v-model but it should just pass a prop since it's not modifying its modelValue prop. Otherwise you have to provide the inheritAttrs: false option to it so it doesn't inherit the binding and event listener from its parent and put it on the Test component, which conflict with the added v-model. That's also why a wrapper fixes the problem.

You can find more information at existing RFCs like vuejs/rfcs#31