Multiple inheritance in Solidity

Question

I have a contract C that is Ownable so I can use ownerOnly on its admin functions. Recently, I added some functionality that I'm going to start using in other projects. I refactored the functionality out to a second contract Refactored, so now contract C is Refactored, Ownable.

But then I discovered that some of the functionality of Refactored needs to be protected as well, so I added contract Refactored is Ownable and everything broke with a Linearization of inheritance graph impossible error.

I ended up leaving Ownable on Refactored and removing it from C - and that solved it - but now it looks like C is using ownerOnly functionality without including Ownable - i.e. it works, but doesn't look good.

Is there any way I can have both contracts be Ownable and still have one of them inherit the other? (I'd like to avoid having a variable in C be of type Refactored because then I'll have to expose a bunch of getter functions, negating the whole refactoring).

Answer 1

I ended up leaving Ownable on Refactored and removing it from C - and that solved it - but now it looks like C is using ownerOnly functionality without including Ownable

I don't know why you'd think that. That's how inheritence works in pretty much any object-oriented language. If B is A's child and C is B's child, A is C's parent.

To answer your question, no, there's no way of doing what you're trying to do. You'll have to do with how it is currently.