use ethers abi parser to validate function abi

src/conditions/base/contract.ts

@@ -1,3 +1,4 @@
+import { ethers } from 'ethers';
 import Joi from 'joi';
 
 import { ETH_ADDRESS_REGEXP } from '../const';
@@ -6,31 +7,51 @@ import { RpcCondition, rpcConditionRecord } from './rpc';
 
 export const STANDARD_CONTRACT_TYPES = ['ERC20', 'ERC721'];
 
-const functionAbiVariable = Joi.object({
- internalType: Joi.string(), // TODO is this needed?
- name: Joi.string().required(),
- type: Joi.string().required(),
-});
-
 const functionAbiSchema = Joi.object({
  name: Joi.string().required(),
  type: Joi.string().valid('function').required(),
- inputs: Joi.array().items(functionAbiVariable),
- outputs: Joi.array().items(functionAbiVariable),
- // TODO: Should we restrict this to 'view'?
- stateMutability: Joi.string(),
+ inputs: Joi.array(),
+ outputs: Joi.array(),
+ stateMutability: Joi.string().valid('view', 'pure').required(),
 }).custom((functionAbi, helper) => {
+ // Is `functionABI` a valid function fragment?
+ let asInterface;
+ try {
+ asInterface = new ethers.utils.Interface([functionAbi]);
+ } catch (e: unknown) {
+ const { message } = e as Error;
+ return helper.message({
+ custom: message,
+ });
+ }
+
+ if (!asInterface.fragments) {
+ return helper.message({
+ custom: '"functionAbi" is missing a function fragment',
+ });
+ }
+
+ if (asInterface.fragments.length > 1) {
+ return helper.message({
+ custom: '"functionAbi" must contain exactly one function fragment',
+ });
+ }
+
+ // Now we just need to validate against the parent schema
  // Validate method name
  const method = helper.state.ancestors[0].method;
- if (functionAbi.name !== method) {
+ const functionFragment = asInterface.fragments.filter(
+ (f) => f.name === method
+ )[0];
+ if (!functionFragment) {
  return helper.message({
- custom: '"method" must be the same as "functionAbi.name"',
+ custom: '"functionAbi" does not contain the method specified as "method"',
  });
  }
 
  // Validate nr of parameters
  const parameters = helper.state.ancestors[0].parameters;
- if (functionAbi.inputs?.length !== parameters.length) {
+ if (functionFragment.inputs.length !== parameters.length) {
  return helper.message({
  custom: '"parameters" must have the same length as "functionAbi.inputs"',
  });
@@ -39,7 +60,7 @@ const functionAbiSchema = Joi.object({
  return functionAbi;
 });
 
-export const contractConditionRecord: Record<string, Joi.Schema> = {
+export const contractConditionRecord = {
  ...rpcConditionRecord,
  contractAddress: Joi.string().pattern(ETH_ADDRESS_REGEXP).required(),
  standardContractType: Joi.string()

test/unit/conditions/base/contract.test.ts

@@ -7,7 +7,7 @@ import {
 import { ContractCondition } from '../../../../src/conditions/base';
 import { USER_ADDRESS_PARAM } from '../../../../src/conditions/const';
 import { fakeWeb3Provider } from '../../../utils';
-import { testContractConditionObj } from '../../testVariables';
+import { testContractConditionObj, testFunctionAbi } from '../../testVariables';
 
 describe('validation', () => {
  it('accepts on a valid schema', () => {
@@ -103,30 +103,10 @@ describe('accepts either standardContractType or functionAbi but not both or non
 });
 
 describe('supports custom function abi', () => {
- const fakeFunctionAbi = {
- name: 'myFunction',
- type: 'function',
- inputs: [
- {
- name: 'account',
- type: 'address',
- },
- {
- name: 'myCustomParam',
- type: 'uint256',
- },
- ],
- outputs: [
- {
- name: 'someValue',
- type: 'uint256',
- },
- ],
- };
  const contractConditionObj = {
  ...testContractConditionObj,
  standardContractType: undefined,
- functionAbi: fakeFunctionAbi,
+ functionAbi: testFunctionAbi,
  method: 'myFunction',
  parameters: [USER_ADDRESS_PARAM, ':customParam'],
  returnValueTest: {

test/unit/testVariables.ts

@@ -48,6 +48,7 @@ export const testContractConditionObj = {
 export const testFunctionAbi = {
  name: 'myFunction',
  type: 'function',
+ stateMutability: 'view',
  inputs: [
  {
  internalType: 'address',
@@ -67,5 +68,4 @@ export const testFunctionAbi = {
  type: 'uint256',
  },
  ],
- stateMutability: 'view',
 };