Revert

What is Revert?

A revert is a smart contract instruction that halts execution and rolls back all state changes from a transaction. It is the primary mechanism contracts use to enforce rules and reject invalid operations.

How does Revert work?

1. A contract evaluates a condition via a require statement during execution.
2. If the condition fails, a revert is triggered and all changes are rolled back.
3. The user still pays gas for computation up to the point of failure.
4. The transaction is recorded on-chain with a "Reverted" status and an error message.

Why does Revert matter?

Reverts enable atomic all-or-nothing transactions, ensuring a multi-step operation either completes fully or has zero effect. This is essential for safe financial interactions on-chain.

Key features of Revert

• Complete rollback of all state changes within the failed transaction
• Gas is still consumed up to the point of failure
• Error messages help developers and users diagnose issues
• Enables atomic multi-protocol transactions

Examples of Revert

Trying to swap more tokens than exist in a Uniswap pool triggers a revert. A mint contract reverts if the 10000 token supply cap has already been reached.