vnode not work for functional from v2.5.14

[yozman]

Version

2.5.15

Reproduction link

https://codepen.io/yozman/pen/JLdaRZ

Steps to reproduce

the codepen is a demo for v2.5.13,
it's works well,
when change to v2.5.14 or v2.5.15,
there is blank output

What is expected?

work well as v2.5.13

What is actually happening?

blank output

[yozman]

@yyx990803
need ur help,
could u plz fix it.

[LinusBorg]

Mentioning Evan will not get your help faster, we read every issue and priorize all issues accoring to the grater needs of Vue and the ecosystem.

[jkzing]

By using v-bind="item", you are converting a VNode instance into a "vnode like" object, that's the reason you are not seeing your expected result.

Although that usage worked in previous version, I recommend to use a more standard way:

Vue.component('value-vnode', {
  functional: true,
  render: (h, { props }) => props.value
})

<div>
  <op-vnode :value="$slots.default"/>
</div>

[posva]

hhm, not sure you should v-bind the whole vnode, the type gets lost. If you only need to bind one value, just use one single prop:

pretty much what @jkzing said (as I was writing this before his comment got published 😆 )

[HerringtonDarkholme]

OP's usage should be covered in #7765.

For more board usage, should we support v-bind for non-plain object?

On the other hand, returning a non vnode data in render function doesn't make much sense. It might invalidate JS engine's type speculation, which might harm runtime performance(not sure).

[yozman]

@jkzing
maybe there should be a helper function createVNode
to change vnode like to vnode
or how can I use this cloneVNode?

[jkzing]

Actually I'm pretty agree with @HerringtonDarkholme, that render function should return only vnode data. As returning non vnode object was working in previous version, a warning would be more reasonable than a fix?

[yozman]

@jkzing
I don't think so.
v-bind is a alias like jsx {...props}
but in this case it not work like {...props}

what is v-bind mean ?
bind something whatever what it is,
if u don't want to support this,
u guys should change v-bind to v-bind.object I think

[HerringtonDarkholme]

bind something whatever what it is,

Sadly that's not how Vue works at all.

Vue's vnode has two domProps and attrs fields and they are handled differently internally.
This means Vue has to create two separate objects to extract props and attrs. https://github.com/vuejs/vue/blob/dev/src/core/instance/render-helpers/bind-object-props.js#L42-L44

On the other hand, React flavor's JSX only have one props. So passing object as is makes sense.

[yozman]

@HerringtonDarkholme
not matter what Vue work as,
the meaning is for v-bind should be,
or u guys should change v-bind to v-bind:object

[LinusBorg]

Well, you don't get to define what v-bind means.

[yozman]

@HerringtonDarkholme @jkzing @LinusBorg
it's works well untill 2.5.13
should this be a breaking change?

[yozman]

if it is a breaking change,
should be on 3.x
not 2.x

[LinusBorg]

it's works well untill 2.5.13
should this be a breaking change?

It was never intended to work, so no, it's not a breaking change

or u guys should change v-bind to v-bind:object

Now that, on the other hand, would be a very big breaking change, because props named object would no longer work as expected.