(Refactor) Ensure user has at least one address

[phahulin]

Before filing an issue, please provide the following information:

• What is it? (leave one option)
  • (Refactor) proposal (i.e. no new features or updates, just code optimization/library updates)

Make explicit check that user has at least one address registered. If not, return empty string https://github.com/poanetwork/poa-popa/blob/4a3cd0f2ab913383bbcf85ad51828acd66461ac2/blockchain/contracts/ProofOfPhysicalAddress.sol#L185-L190

[fvictorio]

Doing this would mean removing the checkUserExists modifier, since users are removed when their only address is removed. Are you OK with that?

[phahulin]

Let's keep both checkUserExists and add the new check. Auditor's concern is "for the future development" when it might be possible to have user with 0 addresses or popa contract will be separated into multiple contracts

[fvictorio]

Sorry, I don't follow.

The checkUserExists modifier throws an error if the user doesn't exist. If we want to return an empty string, we need to remove the modifier.

We can do something like this:

    function userLastSubmittedName(address wallet)
    public constant returns (string)
    {
        if (userExists(wallet)) {
            return users[wallet].physicalAddresses[users[wallet].physicalAddresses.length-1].name;
        }

        return "";
    }

[phahulin]

Oh, yes, you're right, thanks. Let me check with auditors

[phahulin]

@fvictorio so the concern is the following: in the current implementation users always have addresses, but it might happen in the future that a user can exist but has no addresses. So suggestion is to keep the modifier and add explicit check that physicalAddresses.length>0 before getting name. If physicalAddresses.length==0 - return empty string.