Versioning

[blockchain-iot]

Versioning

[jaszczw]

There is a couple of ways of achieving that:

You can use delegatecall available in solidity that will call a method in another smart contract together with changeable variable currentVersionAddress we can call 'current' version of the contract from our 'proxy'.

example from https://github.com/shaunazzopardi/smart-contract-versioning called 'Proxy/Interface method'

    address currentVersion = <someAddress>;
    
    <type> <varName>;
    function <methodName>() public returns(<type>){
        if(currentVersion.delegatecall(msg.data)){
            returns <varName>;
        }
        else{
            revert();
        }
    }

Only Owner of the contract can modify the currentVersionAddress.

In more details it concept is explained on https://ethereum.stackexchange.com/questions/2404/upgradeable-smart-contracts

One of the limits of that approach is that you can have only variables available in the original contract, meaning you would have to either know a priori what will you require or provide a magic map of anything.

Sources:

1. https://github.com/shaunazzopardi/smart-contract-versioning
2. https://ethereum.stackexchange.com/questions/2404/upgradeable-smart-contracts
3. https://forum.ethereum.org/discussion/4595/versioning-of-smart-contracts

[michalmikolajczyk]

Versioning best practices
https://blog.zeppelin.solutions/proxy-libraries-in-solidity-79fbe4b970fd
https://medium.com/rocket-pool/upgradable-solidity-contract-design-54789205276d

[michalmikolajczyk]

Consider moving to Zeppelin OS https://docs.zeppelinos.org/docs/start.html