Assigning the ownership in the constructor creates issues for factory patterns

[thegostep]

This creates additional 5k deployment cost to update the ownership as a part of the deployment. I recommend using an initializer function which accepts an arbitrary address as the owner.

openzeppelin-contracts/contracts/access/Ownable.sol

Lines 26 to 30 in ec8efd5

	constructor () {
	address msgSender = _msgSender();
	_owner = msgSender;
	emit OwnershipTransferred(address(0), msgSender);
	}

[frangio]

I agree that using msg.sender in the constructor was a mistake. As far as I can tell there is nothing we can do in a backwards compatible way, unless Solidity supports optional arguments at some point.

[Amxx]

That is not exactly what you are asking for, but if you plan to have your contract inherit from Ownable AND have an initializer, maybe the initializer could use the internal function proposed in #2464

[thegostep]

Nice - that's also a much needed improvement but I would still request removing setting ownership in the constructor

[frangio]

We've come to the following conclusion. We would have slightly preferred to have had the owner constructor argument since the beginning, but at this point we don't want to make the breaking change in the existing contracts.

FWIW, the upcoming storage cost changes in the Berlin hard fork, if I'm reading them correctly, seem to drastically reduce the cost of the extra SSTORE caused by having to use an internal setter in the constructor body after the default value of msg.sender has already been set.