Error

In Solidity, developers can define errors in three main forms: revert, require, and assert. The main differences between these methods from a functional perspective are two-fold:

1. Whether they can throw developer-defined error reasons;
2. Whether they can throw developer-defined errors carrying variables;

The main differences are as follows:

Type	Custom Reason	Carries Variable	Example
revert	✅	✅	Reason: UnauthorizedAccess(0x05D01CAF54524A610CCF187082201120757f7AE5)
require	✅	❌	Reason: UnauthorizedAccess
assert	❌	❌	Reason: Assertion violated

DemoCode

Below, we use the three forms of errors to observe the changes in gas usage:

contract Error {
    error UnauthorizedAccess();

    // gas: 164
    function errorRevert() external pure {
        if (true) revert UnauthorizedAccess();
    }

    // gas: 268
    function errorRequire() external pure {
        require(false, "UnauthorizedAccess");
    }

    // gas: 180
    function errorAssert() external pure {
        assert(false);
    }
}

the gas optimization suggestions are as follows:

🌟1. revert is the most recommended as it can throw error messages as well as related variables.

🌟2. The string in require is stored on-chain, which not only consumes more gas but also increases the contract size. It is recommended to choose based on actual needs.

🌟3. If there's a scenario where assert is used, it's suggested to replace it with revert.