Vue.js version

2.0.2

Steps to reproduce

1. Create component

Vue.component('testcomponent', {
  render: h => h('div', 'contain')
})

2. Use the components within the parent component template with className

  <div id="appcomponent">
    <testcomponent class="testclass" />
  </div>

What is Expected?

Expected to render on the server side

  <div id="appcomponent">
    <div class="testclass">contain</div>
  </div>

Similarly, as the client-side

What is actually happening?

The server side is not renders classes in dynamically generated components

  <div id="appcomponent">
    <div>contain</div>
  </div>

At the same time, the client side, renders everything with classes

  <div id="appcomponent">
    <div class="testclass">contain</div>
  </div>

This behavior causes a twitch of the interface, due to the belated addition of classes with styles.
Also incorrect display if the js file not to load on slow internet.