State Migration Verifier and Finalizer

WHAT IT DOES

The State Migration Verifier and Finalizer enables developers to verify that state data has been correctly copied during contract migrations and to finalize the migration process by marking the old contract as deprecated. Verification ensures that all user positions, token balances, storage slots, contract variables, mapping data, array data, and struct data have been accurately transferred to the new contract. Finalization is the final step in a migration—it marks the old contract as deprecated, preventing further interaction and signaling that the migration is complete.

The tool reads old contract state, new contract state, user positions, token balances, storage slots, contract variables, mapping data, array data, struct data, verification parameters, and migration history. It performs hash comparison or key-value verification to confirm that data was correctly copied. The tool supports three operation modes: Verify Only (check data integrity without making changes), Finalize (mark old contract as deprecated), and Verify & Finalize (perform both operations).

HOW TO USE

1. Connect your wallet using the Connect button. The tool automatically detects your connected address and network.

2. Select the network where your contracts are deployed using the network dropdown.

3. Enter the old contract address (source) and the new contract address (destination).

4. Enter the data mapping keys (comma-separated) you want to verify.

5. Select the operation mode: Verify Only, Finalize, or Verify & Finalize.

6. Set a gas limit appropriate for the verification and/or finalization.

7. Click "Preview verification" to see what will be verified and/or finalized.

8. Review the verification details in the preview panel.

9. Click "Execute" to submit the transaction through your wallet.

10. The tool will read data from both contracts, compare it, and finalize the migration if requested.

TECHNICAL MECHANISM

The tool reads state data from both the old and new contracts using view functions or direct storage slot access. For each data key, it retrieves the value from both contracts and compares them. Verification uses hash comparison (keccak256) of the serialized data or direct key-value matching. If verification passes and finalization is requested, the tool calls the new contract's finalizeMigration function, which typically sets the old contract's address as deprecated, emits a finalization event, and updates the contract state to indicate that the migration is complete. The tool also checks the migration status before executing to prevent double-finalization. After finalization, the old contract may be paused or marked inactive to prevent further state changes.

WHAT IT CANNOT SEE

This tool cannot verify that the price feed is accurate or reliable; it relies on the contracts' internal state. It cannot detect if the oracle has been compromised or manipulated. It cannot ensure that verification will execute at the optimal price due to gas costs. It cannot guarantee that verification will complete successfully if the new contract has not been audited or contains bugs. It cannot verify that the contracts have not been modified beyond the intended migration. It cannot detect if the data verification is optimal or if the data structure is correctly aligned. It cannot recover funds if execution fails due to contract bugs, insufficient gas, out-of-gas errors, or blockchain reorgs. It cannot verify that data being verified is legitimate or has not been tampered with. It cannot predict storage slot collisions or conflicts between the old and new contracts. It cannot guarantee execution during extreme network congestion or high gas price conditions. It cannot detect if the new contract has been compromised. It cannot prevent the user from canceling or modifying verification/finalization parameters through other interfaces. It cannot ensure that verification is economically optimal or that gas costs do not exceed the migration value. It cannot guarantee that all data has been correctly verified or that finalization will be irreversible. It cannot ensure that the old contract will be properly deprecated.

PLEASE NOTE

This tool is designed for EVM-compatible blockchains (Ethereum, Polygon, Arbitrum, Optimism, Base, BSC, Avalanche, Fantom, and others). It requires an active wallet connection and sufficient native currency for gas fees. Always verify the old and new contract addresses, data keys, and operation mode before executing. Finalization is irreversible—ensure verification passes before finalizing. The tool is provided as-is with no warranty; users assume full responsibility for their transactions and should exercise caution when verifying and finalizing migrations. For mainnet usage, ensure both contract versions have been audited and you understand the risks of finalization including irreversible deprecation.