empty class is rendered although I return false

[271ch]

Version

2.6.10

Reproduction link

https://codesandbox.io/s/vue-template-cob7z

Steps to reproduce

Execute the application and look at the the 2nd level div element in the body.

What is expected?

I expect <div>

What is actually happening?

I get <div class="">

This behaviour is in contrast with the otherwise normal behaviour of the vue framework of hiding elements with a false value.

[posva]

class and style have a proper handling and, differently from other attributes, when set to undefined, they keep the empty attribute on the element, probably for performance reasons