When a props property is undefined, component does not render the received style.

[hareku]

Version

3.0.0-alpha.5

Reproduction link

https://codepen.io/hareku/pen/PoqGdYB

Steps to reproduce

1. Render ChildWithProps.
2. Render ChildWithoutProps.

What is expected?

The span elements of ChildWithProps and ChildWithoutProps should have `style="font-size: red".

What is actually happening?

ChildWithoutProps does not have `style="font-size: red".

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I think, even props is undefined, components should work the same as ChildWithProps.

[loiacon]

It appears to be something on attributes merge.

https://github.com/vuejs/vue-next/blob/a840e7ddf0b470b5da27b7b2b8b5fcf39a7197a2/packages/runtime-core/src/componentRenderUtils.ts#L79-L92

[underfin]

vuejs/rfcs#92.
If components with no props declaration, will be not implicit fallthrough attrs.

[yyx990803]

Maybe class and style should be special cased even when no props are declared.

[ysj16]

Maybe class and style should be special cased even when no props are declared.

All attrs will fallthrough in vue 2.x

[yyx990803]

@ysj16 see the RFC linked in the commit.