Why Sender address emitted in event differs from saved in storage?

Question

The wallet address that is sent through event differs from the one stored in contract

Hi, I have a contract that is deployed to development network through truffle. I trigger function that looks like this:

    struct Round {
        bool isValue;
        uint32 id;
        RoundState state;
        address[] addresses;
        RoundBet[] bets;
        mapping(address => bool) betUsers;
        mapping(address => uint256) userBets;
        uint256 winTicket;
        uint256 amount;
        uint256 lastTicket;
        address winner;
    }
.....

    event roundBet(
        address user,
        uint256 amount,
        uint256 start,
        uint256 end
    );

......
function test() payable public {
        Round storage round = roundsHistory[currentRound];
        require(round.isValue == true);
        require(round.state == RoundState.started);
        require(msg.value >= MIN_BET);
        uint256 amount = msg.value - msg.value % MIN_STEP;
        if(!round.betUsers[msg.sender]){
            round.addresses.push(msg.sender);
            round.betUsers[msg.sender] = true;
        }
        round.userBets[msg.sender] += amount;
        uint256 sticket = round.lastTicket + 1;
        uint256 eticket = sticket + amount;
        uint256 length = round.bets.push(RoundBet(true, sticket, eticket, msg.sender, amount));

        round.amount += amount;
        round.lastTicket = eticket;

        if(round.addresses.length == 2){
            round.state = RoundState.running;
            emit roundTimerStart(currentRound);
        }
        emit roundBet(msg.sender,amount, sticket, eticket);
}

AS you can see I emit roundBet event at the end of function call. The problem is that value of "user" of that event differs from msg.sender that is stored in round.addresses(values stored in round.addresses - is currect and the one emited - is wrong)

score 1 · Answer 1 · answered Jan 09 '19 at 10:17

1

If you are using Metamask, keep in mind that it does not switch the account set as msg.sender to the contract, it seems to use the first account (0) to sign every transaction.

We encountered the same problem during a school project.

answered Jan 09 '19 at 10:17

SomeDutchGuy

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Ok but msg.sender does not equal to account[0] either. It's just some kind of random number prefixed 0x for example all accounts that I use start with 0x4 but the value returned by emit starts with 0x9 and has characters in it. – 1099511627776 Jan 09 '19 at 11:21
2

I've just figured that may be emit crops first 2 characters from address – 1099511627776 Jan 09 '19 at 11:22
@1099511627776 Was it the case? – saman.shahmohamadi Jan 09 '19 at 12:38
Did you manage to solve the issue? You might want to share it in that case and mark it as the answer for others encountering the same problem. – SomeDutchGuy Jan 09 '19 at 12:46
Well I did not manage to solve it directly but I've found a workaround – 1099511627776 Jan 09 '19 at 19:22

score 1 · Answer 2 · answered Jan 16 '19 at 06:22

First of all about platform. It was tron not ethereum. May be in ethereum there is no such issue. So what I did:

I do not pass address in event. I save it in internal structure
In event I do pass index of saved address in structure
I've wrote a separate method that returns address (and other usefull info) from internal structures by its index.

So by using this workaround I was able to get needed information from contract.

Why Sender address emitted in event differs from saved in storage?

2 Answers2