Looks like this is because props are not properly de-duped when merged. However it seems a bad idea to have duplicate props in multiple mixins. I don't think this is the mixin mechanism's problem, but rather how you use mixins...

IMO when you use multiple mixins, they should each serve a distinct purpose. If you have two mixins that have overlapping responsibilities then you probably need to rethink the design.

Thanks, having duplicated props is actually a bad idea, I think I should remove the dep on A for B and C, then require the mixins [A,B,C] in component D:)

Just curious. Imagine I have a mixin with some prop, I need to redefine its prop default value in component. How can I do it?

@OEvgeny it will probably work like described in docs, not sure about props thought: http://rc.vuejs.org/guide/mixins.html#Option_Merging

@OEvgeny that sounds like a bad idea to me. Ideally you don't want the sub fields of an option to be merged from multiple sources, especially when it is an object like a prop. It makes your code very hard to reason about. Hooks on the other hand makes more sense.

@yyx990803 @azamat-sharapov thank you. I also think there is something wrong with my approach... :)