Transaction Error. Exception thrown in contract code. REVERT opcode when sending ETH to crowdsale

Question

I wanted to follow the tutorial - https://blog.zeppelin.solutions/how-to-create-token-and-initial-coin-offering-contracts-using-truffle-openzeppelin-1b7a5dae99b6 - but there was a new release - https://github.com/OpenZeppelin/zeppelin-solidity/releases/tag/v1.7.0 - so I'm trying to figure it out...

Actual code is verified on Etherscan.

Crowdsale: https://ropsten.etherscan.io/address/0x018ea8f3fef7bd14c7bff98e898842925f05e6ea#code

Coin: https://ropsten.etherscan.io/address/0x37ca578d3d847d27741b2ffc033419a7d11b7bef#code

My account sending ETH to crowdsale: https://ropsten.etherscan.io/address/0x85a363699c6864248a6ffca66e4a1a5ccf9f5567

Transaction hash: https://ropsten.etherscan.io/tx/0x7f99bca20b767073eb48ed2e6d01186c55bcc97ee8316523977e15c4286f6c5a

Here is a short video of me explaining what I'm doing: https://youtu.be/oKP9ea5PNho

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Looking at the code: https://github.com/OpenZeppelin/zeppelin-solidity/blob/3c489127306d09dc08c6a22263134fb5413d2f80/contracts/crowdsale/Crowdsale.sol#L48

function Crowdsale(uint256 _rate, address _wallet, ERC20 _token) public

I instantiate coin and crowdsale in the following way:

contract MailHustleCrowdsale is Crowdsale {

  uint256 _rate = 1000; 
  address _wallet = 0x315f80c7caacbe7fb1c14e65a634db89a33a9637;
  ERC20 _token = new MailHustleCoin();

  function MailHustleCrowdsale() Crowdsale(_rate, _wallet, _token) {          
  }
}

My guess is that the error is somewhere here but cannot figure the working syntax...

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Alternative approach:

How to reference coin contract already onchain?

If including the original source code isn't practical, an easy way to work around it is just to make a stub contract above your own contract containing the function signature of the function you want to call.

For simplicity I've decided to include everything in a single file.

Answer 1

Credit goes to Vidor:

Maybe you can earn some Stack Overflow reputation and put these pointers into the original question?

too much hassle to little fun

I understand, I’ll do this then

I'm realizing I know so little and I should not be touching the code.

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One

function mint(address _to, uint256 _amount) onlyOwner canMint public returns (bool)

Only owner can mint. Coin creation should be in the crowdsale contract.

Two

function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal { require(MintableToken(token).mint(_beneficiary, _tokenAmount)); }

Instead of

function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal { token.transfer(_beneficiary, _tokenAmount); }

Currently you are transferring tokens from the sender address which has 0. You want to go for a minting strategy which is better

Here is TX that works: https://ropsten.etherscan.io/tx/0x1b4c11eee16e06bc53a273a9a805ea11def461c9f81847edb2d8f95daa273ae5

(you can navigate to contract to see the working source)

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Here is a better example: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/examples/SampleCrowdsale.sol