👀 Views: 32 💬 Answers: 1 📅 Created: 2025-06-01

solidity ethereum smart-contracts debugging Solidity

I need some guidance on I'm relatively new to this, so bear with me. I've looked through the documentation and I'm still confused about I'm working on a project using Solidity version 0.8.17 where I have two smart contracts: `Token` and `Crowdsale`. The `Crowdsale` contract is supposed to call a function in the `Token` contract to transfer tokens to participants. However, I'm working with a `revert opcode` behavior every time I attempt to execute this function from the `Crowdsale`. Here's a simplified version of both contracts: ```solidity // Token.sol pragma solidity ^0.8.17; contract Token { mapping(address => uint256) public balances; uint256 public totalSupply; constructor(uint256 _initialSupply) { totalSupply = _initialSupply; balances[msg.sender] = _initialSupply; } function transfer(address _to, uint256 _amount) public returns (bool) { require(balances[msg.sender] >= _amount, "Insufficient balance"); balances[msg.sender] -= _amount; balances[_to] += _amount; return true; } } // Crowdsale.sol pragma solidity ^0.8.17; import "./Token.sol"; contract Crowdsale { Token public token; constructor(address _tokenAddress) { token = Token(_tokenAddress); } function buyTokens(uint256 _amount) public { require(token.transfer(msg.sender, _amount), "Transfer failed"); } } ``` I deploy the `Token` contract and then the `Crowdsale` contract, passing the `Token` contract address. When I call `buyTokens` from an external account, I get the following behavior: ``` Transaction reverted: revert opcode ``` I've checked the balances, and the deployer of the `Token` has sufficient tokens. The `transfer` function seems to be straightforward, but I'm puzzled as to why it's reverting. I've confirmed that the `Crowdsale` contract is correctly initialized with the `Token` contract address. I've also tried debugging with Remix, but I haven't found any obvious issues. Can someone guide to figure out what might be going wrong here? My development environment is Linux. How would you solve this? I'm using Solidity latest in this project. How would you solve this?