Solidity Programming Language – Revert and Assert

Mainly used for error handling.

In Solidity, revert and assert are two mechanisms used for handling errors and unexpected conditions in smart contracts. While they might seem similar, they serve slightly different purposes:

Revert: The revert keyword is used to revert the current transaction due to an error condition or to revert the state changes made within a contract function. It allows you to provide a custom error message that explains why the transaction is reverting. Reverting is typically used for expected conditions where it’s acceptable for the transaction to fail without causing any harm to the blockchain state.

Assert: The assert keyword is used to ensure that a condition is always true. If the condition evaluates to false, the transaction is reverted, and any state changes are rolled back. Assert is used to check for internal errors or invariant violations that should never occur if the contract is functioning correctly.

In summary, revert is used to handle expected conditions and provide custom error messages, while assert is used to enforce internal consistency and invariant conditions within the contract. Both are important for writing secure and robust smart contracts.

The key difference between require and revert lies in their intended use cases and semantics. require is typically used for input validation and to enforce preconditions, while revert is more versatile and can be used for any situation where you need to revert the transaction with a custom error message or handle exceptional conditions. Additionally, require is often used for conditions that are expected to hold true in normal circumstances, while revert is used for exceptional or unexpected conditions.

Use of assert -> is used for 2 thing: Bug identification and Security

Advantages:

1) This do the same thing while returning the unused gas.

2) Undo the value of state variable if it change.

Revert having power of custom error.

Code:

Output: