VNode.elm missing for nested slots after component update

[jkzing]

Version

2.2.6

Reproduction link

https://jsfiddle.net/jingkaizhao/f11tpysz/5/

Steps to reproduce

1. open and run fiddle
2. open chrome devtool
3. click 'update' button
4. see result in console

What is expected?

In updated hook, vnode inside slots children (this.$slots.default) should have a reference to its DOM element on property vnode.elm

What is actually happening?

vnode.elm is undefined

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Did some investigation on it.
It just happened on nested component, (<slot> as children for another component). And it only happened after patching, it means in the initial stage (mounted hook), the vnode has correct reference to its DOM node, but after update (updated hook), the elm reference is missing.

[HerringtonDarkholme]

It seems slot vnode will be copied across different components. So the vnode in nested copmonent is not updated. Still needs deeper investigation...

[yyx990803]

This is somewhat expected behavior because slot nodes are shallow-cloned during render, so when nested passes the slot nodes down to block, block clones the slot nodes and then patches them (adding .elm in the process), however, the slot nodes in nested remain non-patched.

This is a wontfix because you should not be relying on vnode.elm in your render functions. This is not part of intended usage for vnodes.