Ethereum Improvement ProposalsAbstract
This EIP standardizes an interface containing a single function, multicall, allowing EOAs to call multiple functions of a smart contract in a single transaction, and revert all calls if any call fails.
Motivation
Currently, in order to transfer several ERC-721 NFTs, one needs to submit a number of transactions equal to the number of NFTs being tranferred. This wastes users' funds by requiring them to pay 21000 gas fee for every NFT they transfer.
Specification
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 and RFC 8174.
Contracts implementing this EIP must implement the following interface:
pragma solidity ^0.8.0;
interface IMulticall {
/// @notice Takes an array of abi-encoded call data, delegatecalls itself with each calldata, and returns the abi-encoded result
/// @dev Reverts if any delegatecall reverts
/// @param data The abi-encoded data
/// @returns results The abi-encoded return values
function multicall(bytes[] calldata data) external virtual returns (bytes[] memory results);
/// @notice OPTIONAL. Takes an array of abi-encoded call data, delegatecalls itself with each calldata, and returns the abi-encoded result
/// @dev Reverts if any delegatecall reverts
/// @param data The abi-encoded data
/// @param values The effective msg.values. These must add up to at most msg.value
/// @returns results The abi-encoded return values
function multicallPayable(bytes[] calldata data, uint256[] values) external payable virtual returns (bytes[] memory results);
}
Rationale
Needs discussion.
Backwards Compatibility
This is compatible with most existing multicall functions.
Reference Implementation
pragma solidity ^0.8.0;
/// Derived from OpenZeppelin's implementation
abstract contract Multicall is IMulticall {
function multicall(bytes[] calldata data) external virtual returns (bytes[] memory results) {
results = new bytes[](data.length);
for (uint256 i = 0; i < data.length; i++) {
(bool success, bytes memory returndata) = address(this).delegatecall(data);
require(success);
results[i] = returndata;
}
return results;
}
}
Security Considerations
Needs discussion.
Copyright
Copyright and related rights waived via CC0.