What are the debugging techniques in Hardhat?

Hardhat provides powerful debugging capabilities. Here are the main debugging techniques:

1. Console.log Debugging

Use console.log in Solidity contracts:

solidity
import "hardhat/console.sol";

contract MyContract {
    function setValue(uint256 _value) public {
        console.log("Setting value to:", _value);
        value = _value;
        console.log("Value set successfully");
    }
}

2. Transaction Tracing

Use hardhat --verbose to view detailed transaction information:

bash
npx hardhat test --verbose

Capture error stacks in tests:

javascript
try {
  await contract.someFunction();
} catch (error) {
  console.log(error);
}

3. Hardhat Network Console

Start interactive console:

bash
npx hardhat console

Execute commands in the console:

javascript
const Contract = await ethers.getContractFactory("MyContract");
const contract = await Contract.deploy();
await contract.setValue(42);
console.log(await contract.value());

4. Debugging Tests

Run tests with --debug flag:

bash
npx hardhat test --debug

5. Viewing Events

Listen to contract events:

javascript
contract.on("EventName", (arg1, arg2, event) => {
  console.log("Event emitted:", arg1, arg2);
});

6. State Snapshots

Use snapshot functionality to quickly reset state:

javascript
const snapshot = await ethers.provider.send("evm_snapshot", []);
// Perform operations
await ethers.provider.send("evm_revert", [snapshot]);

7. Gas Analysis

Use gas-reporter plugin to analyze gas usage:

bash
npx hardhat test --gas

Best Practices:

• Use console.log extensively during development
• Remove console.sol import in production
• Use meaningful log messages
• Combine events and logs for debugging
• Utilize snapshot functionality to improve testing efficiency