diff --git a/EIPS/eip-1363.md b/EIPS/eip-1363.md index d4984c37998c9f..6f1ce58c7ae4f5 100644 --- a/EIPS/eip-1363.md +++ b/EIPS/eip-1363.md @@ -11,21 +11,23 @@ requires: 20, 165 --- ## Simple Summary -Defines a token interface for [ERC-20](./eip-20.md) tokens that supports executing recipient code after `transfer` or `transferFrom`, or spender code after `approve`. +Defines a token interface for [EIP-20](./eip-20.md) tokens that supports executing recipient contract code after `transfer` or `transferFrom`, or spender contract code after `approve` in a single transaction. ## Abstract -Standard functions a token contract and contracts working with tokens can implement to make a token Payable. +The following are the transfer, transferFrom, approve and callback functions standardized in this EIP: `transferAndCall` and `transferFromAndCall` will call an `onTransferReceived` on a `ERC1363Receiver` contract. `approveAndCall` will call an `onApprovalReceived` on a `ERC1363Spender` contract. ## Motivation -There is no way to execute code after a [ERC-20](./eip-20.md) transfer or approval (i.e. making a payment), so to make an action it is required to send another transaction and pay GAS twice. +There is no way to execute any code on a receiver or spender contract after an [EIP-20](./eip-20.md) `transfer`, `transferFrom` or `approve` so, to make an action, it is required to send another transaction. +This introduces complexity on UI development and friction on adoption because users must wait for the first transaction to be executed and then send the second one. They must also pay GAS twice. -This proposal wants to make token payments easier and working without the use of any other listener. It allows to make a callback after a transfer or approval in a single transaction. +This proposal aims to make tokens capable of performing actions more easily and working without the use of any other listener. +It allows to make a callback on a receiver or spender contract, after a transfer or an approval, in a single transaction. -There are many proposed uses of Ethereum smart contracts that can accept [ERC-20](./eip-20.md) payments. +There are many proposed uses of Ethereum smart contracts that can accept [EIP-20](./eip-20.md) callbacks. Examples could be * to create a token payable crowdsale @@ -33,19 +35,19 @@ Examples could be * paying invoices * making subscriptions -For these reasons it was named as **"Payable Token"**. +For these reasons it was originally named **"Payable Token"**. Anyway you can use it for specific utilities or for any other purposes who require the execution of a callback after a transfer or approval received. -This proposal has been inspired by the [ERC-721](./eip-721.md) `onERC721Received` and `ERC721TokenReceiver` behaviours. +This proposal has been inspired by the [EIP-721](./eip-721.md) `onERC721Received` and `ERC721TokenReceiver` behaviours. ## Specification -Implementing contracts **MUST** implement the [ERC-1363](./eip-1363.md) interface as well as the [ERC-20](./eip-20.md) and [ERC-165](./eip-165.md) interfaces. +Implementing contracts **MUST** implement the [EIP-1363](./eip-1363.md) interface as well as the [EIP-20](./eip-20.md) and [EIP-165](./eip-165.md) interfaces. ```solidity pragma solidity ^0.8.0; -interface ERC1363 /* is ERC20, ERC165 */ { +interface ERC1363 is ERC20, ERC165 { /* * Note: the ERC-165 identifier for this interface is 0xb0202a11. * 0xb0202a11 === @@ -60,56 +62,56 @@ interface ERC1363 /* is ERC20, ERC165 */ { /** * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver * @param to address The address which you want to transfer to - * @param value uint256 The amount of tokens to be transferred + * @param amount uint256 The amount of tokens to be transferred * @return true unless throwing */ - function transferAndCall(address to, uint256 value) external returns (bool); + function transferAndCall(address to, uint256 amount) external returns (bool); /** * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver * @param to address The address which you want to transfer to - * @param value uint256 The amount of tokens to be transferred + * @param amount uint256 The amount of tokens to be transferred * @param data bytes Additional data with no specified format, sent in call to `to` * @return true unless throwing */ - function transferAndCall(address to, uint256 value, bytes memory data) external returns (bool); + function transferAndCall(address to, uint256 amount, bytes memory data) external returns (bool); /** * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver - * @param from address The address which you want to send tokens from + * @param sender address The address which you want to send tokens from * @param to address The address which you want to transfer to - * @param value uint256 The amount of tokens to be transferred + * @param amount uint256 The amount of tokens to be transferred * @return true unless throwing */ - function transferFromAndCall(address from, address to, uint256 value) external returns (bool); + function transferFromAndCall(address sender, address to, uint256 amount) external returns (bool); /** * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver - * @param from address The address which you want to send tokens from + * @param sender address The address which you want to send tokens from * @param to address The address which you want to transfer to - * @param value uint256 The amount of tokens to be transferred + * @param amount uint256 The amount of tokens to be transferred * @param data bytes Additional data with no specified format, sent in call to `to` * @return true unless throwing */ - function transferFromAndCall(address from, address to, uint256 value, bytes memory data) external returns (bool); + function transferFromAndCall(address sender, address to, uint256 amount, bytes memory data) external returns (bool); /** * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender * and then call `onApprovalReceived` on spender. * @param spender address The address which will spend the funds - * @param value uint256 The amount of tokens to be spent + * @param amount uint256 The amount of tokens to be spent */ - function approveAndCall(address spender, uint256 value) external returns (bool); + function approveAndCall(address spender, uint256 amount) external returns (bool); /** * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender * and then call `onApprovalReceived` on spender. * @param spender address The address which will spend the funds - * @param value uint256 The amount of tokens to be spent + * @param amount uint256 The amount of tokens to be spent * @param data bytes Additional data with no specified format, sent in call to `spender` */ - function approveAndCall(address spender, uint256 value, bytes memory data) external returns (bool); + function approveAndCall(address spender, uint256 amount, bytes memory data) external returns (bool); } interface ERC20 { @@ -128,7 +130,7 @@ interface ERC165 { } ``` -A contract that wants to accept token payments via `transferAndCall` or `transferFromAndCall` **MUST** implement the following interface: +A contract that wants to accept ERC1363 tokens via `transferAndCall` or `transferFromAndCall` **MUST** implement the following interface: ```solidity /** @@ -149,18 +151,18 @@ interface ERC1363Receiver { * transfer. Return of other than the magic value MUST result in the * transaction being reverted. * Note: the token contract address is always the message sender. - * @param operator address The address which called `transferAndCall` or `transferFromAndCall` function - * @param from address The address which are token transferred from - * @param value uint256 The amount of tokens transferred + * @param spender address The address which called `transferAndCall` or `transferFromAndCall` function + * @param sender address The address which are token transferred from + * @param amount uint256 The amount of tokens transferred * @param data bytes Additional data with no specified format * @return `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))` * unless throwing */ - function onTransferReceived(address operator, address from, uint256 value, bytes memory data) external returns (bytes4); + function onTransferReceived(address spender, address sender, uint256 amount, bytes memory data) external returns (bytes4); } ``` -A contract that wants to accept token payments via `approveAndCall` **MUST** implement the following interface: +A contract that wants to accept ERC1363 tokens via `approveAndCall` **MUST** implement the following interface: ```solidity /** @@ -181,24 +183,28 @@ interface ERC1363Spender { * approval. Return of other than the magic value MUST result in the * transaction being reverted. * Note: the token contract address is always the message sender. - * @param owner address The address which called `approveAndCall` function - * @param value uint256 The amount of tokens to be spent + * @param sender address The address which called `approveAndCall` function + * @param amount uint256 The amount of tokens to be spent * @param data bytes Additional data with no specified format * @return `bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))` * unless throwing */ - function onApprovalReceived(address owner, uint256 value, bytes memory data) external returns (bytes4); + function onApprovalReceived(address sender, uint256 amount, bytes memory data) external returns (bytes4); } ``` +Note that `transferAndCall`, `transferFromAndCall` MUST revert if the recipient is an EOA address, because EOA recipients do not implement the required ERC1363Receiver interface. +Note that `approveAndCall` MUST revert if the spender is an EOA address, because EOA spenders do not implement the required ERC1363Spender interface. + ## Rationale -The choice to use `transferAndCall`, `transferFromAndCall` and `approveAndCall` derives from the [ERC-20](./eip-20.md) naming. They want to highlight that they have the same behaviours of `transfer`, `transferFrom` and `approve` with the addition of a callback on receiver or spender. +The choice to use `transferAndCall`, `transferFromAndCall` and `approveAndCall` derives from the [EIP-20](./eip-20.md) naming. They want to highlight that they have the same behaviours of `transfer`, `transferFrom` and `approve` with the addition of a callback on receiver or spender contracts. ## Backwards Compatibility -This proposal has been inspired also by [ERC-223](https://github.com/ethereum/EIPs/issues/223) and [ERC-677](https://github.com/ethereum/EIPs/issues/677) but it uses the [ERC-721](./eip-721.md) approach, so it doesn't override the [ERC-20](./eip-20.md) `transfer` and `transferFrom` methods and defines the interfaces IDs to be implemented maintaining the [ERC-20](./eip-20.md) backwards compatibility. +This proposal has been inspired also by many previous informal standards. +Unlike these proposals, [EIP-1363](./eip-1363.md) doesn't override the [EIP-20](./eip-20.md) `transfer` and `transferFrom` methods and defines the interfaces IDs to be implemented maintaining backward compatibility with [EIP-20](./eip-20.md). ## Security Considerations -The `approveAndCall` and `transferFromAndCall` methods can be affected by the same issue of the standard [ERC-20](./eip-20.md) `approve` and `transferFrom` method. +The `approveAndCall` and `transferFromAndCall` methods can be affected by the same issue of the standard [EIP-20](./eip-20.md) `approve` and `transferFrom` method. Changing an allowance with the `approveAndCall` methods brings the risk that someone may use both the old and the new allowance by unfortunate transaction ordering.