UpgradabilityPatterns.sol

UpgradabilityPatterns.sol

pragma solidity ^0.5.10;

// V1

contract AccountV1Storage {
    uint lastInitializedVersion;
    uint a;
}

contract AccountV1 is AccountV1Storage {
    
    function initialize(uint _a) external {
        require(lastInitializedVersion == 0);
        lastInitializedVersion = 1;
        
        a = _a;
    }

    /**
     *  Some functions
     */
}


// V2


contract AccountV2 is AccountV1 {
    
    /**
     *  Some functions
     */
}



// V3

contract AccountV3Storage {
    uint b;
}

contract AccountV3 is AccountV1, AccountV3Storage {
    
    function initialize_v3 (uint _b) external {
        require(lastInitializedVersion == 1);
        lastInitializedVersion = 3;
        
        b = _b;
    }

    /**
     *  Some functions
     */
}