transaction get revert by calling view method from another contract constructor

Question

I havae two contract Record and Register.

Register.sol looks like:

pragma solidity ^0.4.24;

contract Register {
    string private name;

    constructor(string entityname) public {
        name = entityname;
    }

    function getName() public view returns (string username) {
        return name;
    }
}

And in Record.sol:

pragma solidity ^0.4.24;

import "./Register.sol";

contract Record {    
    constructor(address ownerAddr, address providerAddr) public {
        Register(ownerAddr).getName();
        Register(providerAddr).getName();
    }
}

FYI, Record just want to call getName() method of Register contract in its constructor. In the test file I want to create new Record using the following code but got this error VM Exception while processing transaction: revert.

beforeEach('create new Register and Record contract', async () => {
    providerA = await Register.new("Dr Strange", {from: accounts[0]});
    providerB = await Register.new("Maybe", {from: accounts[1]});
    record = await Record.new(providerA.address, providerB.addresss);
})

What should I do?

• Truffle v4.1.14 (core: 4.1.14)

• Solidity v0.4.24 (solc-js)

• Ganache v1.2.2

============================ UPDATE ==============================

I think its the problem of the contract iteself, not the test script. Because using Remix, Register contract can be deployed, but Record cannot even be deployed.

Answer 1

guestA and guestB are not initialized yet. Therefore, their values will be 0. You can't call getName on address 0.

You'll have to initialize these variables with the addresses of the actual deployed Registers.

Answer 2

Take a minute to think what does Register(ownerAddr) even mean.

The constructor of contract Register takes a string, not an address.

That said, here is how I would implement this:

File IRegister.sol:

pragma solidity ^0.4.24;

interface IRegister {
    function getName() public view returns (string);
}

File Register.sol:

pragma solidity ^0.4.24;

import "./IRegister.sol";

contract Register is IRegister {
    string private name;

    constructor(string entityname) public {
        name = entityname;
    }

    function getName() public view returns (string) {
        return name;
    }
}

File Record.sol:

pragma solidity ^0.4.24;

import "./IRegister.sol";

contract Record {
    constructor(address ownerAddr, address providerAddr) public {
        IRegister x = IRegister(ownerAddr);
        IRegister y = IRegister(providerAddr);
        string xName = x.getName();
        string yName = y.getName();
    }
}

Answer 3

Well, problem solved. But someone please tell me why.

The problem is solved by seperating the record contract initializer to it part, namely from

beforeEach('create new Register and Record contract', async () => {
    providerA = await Register.new("Dr Strange", {from: accounts[0]});
    providerB = await Register.new("Maybe", {from: accounts[1]});
    record = await Record.new(providerA.address, providerB.addresss);
})

to

beforeEach('create new Register and Record contract', async () => {
    providerA = await Register.new("Dr Strange", {from: accounts[0]});
    providerB = await Register.new("Maybe", {from: accounts[1]});
})

it("check record initializer", async () => {
    record = await Record.new(providerA.address, providerB.address, "Test");
    record.owner().then(patient => {
        assert.equal(patient, accounts[1], "Owner of the record is wrong!");
    })
})