Vyper: Truffle test read mapping value inside struct

Question

I have the following struct inside my vyper file:

races: public({
  start: timestamp,
  end: timestamp,
  racersBetHash: bytes32[address],
  racersBetAmount: wei_value[address]
}[int128])

Then I call this function:

@public
@payable
def registerRacerBet(_tokenHash: bytes32, _raceID: int128) -> bool:
  self.races[_raceID].racersBetAmount[msg.sender] = msg.value
  self.races[_raceID].racersBetHash[msg.sender] = _tokenHash

  log.NewUserBet(_raceID, msg.sender,
                 self.races[_raceID].racersBetHash[msg.sender],
                 self.races[_raceID].racersBetAmount[msg.sender])
  return True

Inside my truffle test, I'm able to test the correctness of the log, so I'm sure that the struct is properly defined but, if I try to read the value of the struct for the two mapping fiels the call turns back zero value.

I have no problems to read start and end

const currentHashBet = await instance.races__racersBetHash.call(0, '0xf17f52151ebef6c7334fad080c5704d77216b732');

currentHashBet: 0x0000000000000000000000000000000000000000000000000000000000000000

Answer 1

You have a few options, the first one being to write your own function that returns an struct correctly.

In Solidity this could look like

pragma solidity ^0.4.13;

contract Project
{
struct Person {
    address addr;
    uint funds;
}

Person[] people;

function getPeople(uint[] indexes)
    public
    returns (address[], uint[])
{
    address[] memory addrs = new address[](indexes.length);
    uint[]    memory funds = new uint[](indexes.length);

    for (uint i = 0; i < indexes.length; i++) {
        Person storage person = people[indexes[i]];
        addrs[i] = person.addr;
        funds[i] = person.funds;
    }

    return (addrs, funds);
  }
}

I think your problem is that you aren't adding the index of the mapping item. See public-struct-array variable getter.

Let me know if you have any questions, also you might have reversed the order of index and address.

const currentHashBet = await instance.races__racersBetHash.call( '0xf17f52151ebef6c7334fad080c5704d77216b732',0);

If I remember correctly, 0x000 is the null value for addresses, doesn't exist.