Extend EVM's context to expose clause information

vips/VIP-241.md

@@ -3,8 +3,7 @@ VIP: 241
 Title: ERC Contract Adoption
 Description: |
  This Vechain Improvement Proposal (VIP) advocates for the adoption of Ethereum Request for Comment (ERC) standards, aiming to eliminate duplication and enhance interoperability by aligning Vechain contracts with their Ethereum counterparts.
-Author: Darren Kelly, [email protected]
-# TODO
+Author: Darren Kelly, [email protected]
 Discussions: https://vechain.discourse.group/t/add-vip-deprecate-vip-token-standards-in-favour-of-erc/93
 Category: Application
 Status: Draft

vips/VIP-ExtensionV3.md

@@ -0,0 +1,137 @@
+---
+Title: EVM Clause Context
+Description: This VIP proposes an enhancement of the built-in extension contract to provide information about the clauses in the current transaction.
+Author: @databeforedishonor and Darren Kelly ([email protected])
+Discussions: https://vechain.discourse.group/t/mtt-induced-vulnerabilities-in-randomized-events/88
+Category: Core
+Status: Draft
+CreatedAt: 2024-04-18
+
+---
+
+## Overview
+
+The below VIP-XXX proposal outlines an upgrade to the EVM, which will expose clause information to the smart contract, via the built-in `extension` contract
+
+## Motivation
+
+Smart contract developers may want to access information about the current clause being executed. For example, a smart contract can limit the number of clauses in case any malicious actor could exploit the contract via multiple clauses.
+
+## Rationale
+
+The design and decision to expose the clause context in the `extension` contract follows the same pattern as [VIP-191](https://github.com/vechain/VIPs/blob/master/vips/VIP-191.md). This time, the `extension` contract will migrate from V2 to V3 to provide the clause context information.
+
+## Specification
+
+The `extension` contract will be extended to provide the following functions: 
+
+```solidity
+/// @title ExtensionV3 extends EVM global functions.
+contract ExtensionV3 is ExtensionV2 {
+
+ /**
+ * @dev Get the index of the current clause in the transaction.
+ */
+ function txClauseIndex() public view returns (uint) {
+ return ExtensionV3Native(this).native_txClauseIndex();
+ }
+
+ /**
+ * @dev Get the total number of clauses in the transaction.
+ */
+ function txClauseCount() public view returns (uint) {
+ return ExtensionV3Native(this).native_txClauseCount();
+ }
+}
+
+contract ExtensionV3Native is ExtensionV2Native {
+ function native_txClauseCount() public view returns (uint);
+
+ function native_txClauseIndex() public view returns (uint);
+}
+```
+
+## Test Cases
+
+### Test Case 1: Get the index of the current clause in the transaction
+
+Given that `3341b04d` is the function signature of the `txClauseIndex` function, the following curl command should return the index of the current clause in the transaction.
+
+#### Request 1
+
+```bash
+curl --request POST \
+ --url 'http://localhost:8669/accounts/*' \
+ --header 'Accept: application/json, text/plain' \
+ --header 'Content-Type: application/json' \
+ --data '{
+ "clauses": [
+ {
+ "to": "0x0000000000000000000000457874656e73696f6e",
+ "value": "0x0",
+ "data": "0xa6dfac1a"
+ },
+ {
+ "to": "0x0000000000000000000000457874656e73696f6e",
+ "value": "0x0",
+ "data": "0xa6dfac1a"
+ }
+ ]
+}'
+```
+
+#### Response 1
+
+```json
+[
+ {
+ "data": "0x0000000000000000000000000000000000000000000000000000000000000001",
+ ...other fields
+ },
+ {
+ "data": "0x0000000000000000000000000000000000000000000000000000000000000002",
+ ...other fields
+ }
+]
+```
+
+### Test Case 2: Get the total number of clauses in the transaction
+
+Given that `c26ae5e1` is the function signature of the `txClauseCount` function, the following curl command should return the total number of clauses in the transaction:
+
+#### Request 2
+
+```bash
+curl --request POST \
+ --url 'http://localhost:8669/accounts/*' \
+ --header 'Accept: application/json, text/plain' \
+ --header 'Content-Type: application/json' \
+ --data '{
+ "clauses": [
+ {
+ "to": "0x0000000000000000000000457874656e73696f6e",
+ "value": "0x0",
+ "data": "0xa6dfac1a"
+ },
+ ...clause 2,
+ ...clause 3
+ ...clause 4
+ ]
+}'
+```
+
+#### Response 2
+
+```json
+[
+ {
+ "data": "0x0000000000000000000000000000000000000000000000000000000000000004",
+ ...other fields
+ },
+ ...output 2,
+ ...output 3
+ ...output 4
+]
+```
+
+Copyright and related rights waived via [CC0](./LICENSE.md).