Version

3.0.5

Reproduction link

https://jsfiddle.net/f74pxo2h/

  <transition name="empty">
    <div></div>
  </transition>

Steps to reproduce

as shown in JSFiddle

What is expected?

Render component properly

What is actually happening?

Crashed with: TypeError: Cannot read property 'length' of null

if we add v-if or v-show or some children to the div, it will work properly. sample:

<transition name="empty">
    <div>Some content</div>
</transition>
<transition name="empty">
    <div v-if="visible"></div>
</transition>

Has been fixed in https://github.com/vuejs/vue-next/commit/347a8798a4c5f0b426f3ac84a01d752d823fb51b

Not yet released