Add strictArgumentEncodingCheck to BaseContract and use it in contract templates

2 files changed, 127 insertions, 0 deletions

diff --git a/packages/base-contract/src/index.ts b/packages/base-contract/src/index.ts
index a240fb8b6..e354f109e 100644
--- a/packages/base-contract/src/index.ts
+++ b/packages/base-contract/src/index.ts
@@ -82,6 +82,23 @@ export class BaseContract {
         }
         return txDataWithDefaults;
     }
+    // Throws if the given arguments cannot be safely/correctly encoded based on
+    // the given inputAbi. An argument may not be considered safely encodeable
+    // if it overflows the corresponding Solidity type, there is a bug in the
+    // encoder, or the encoder performs unsafe type coercion.
+    public static strictArgumentEncodingCheck(inputAbi: DataItem[], args: any[]): void {
+        const coder = (ethers as any).utils.AbiCoder.defaultCoder;
+        const params = abiUtils.parseEthersParams(inputAbi);
+        const rawEncoded = coder.encode(params.names, params.types, args);
+        const rawDecoded = coder.decode(params.names, params.types, rawEncoded);
+        for (let i = 0; i < rawDecoded.length; i++) {
+            const original = args[i];
+            const decoded = rawDecoded[i];
+            if (!abiUtils.isAbiDataEqual(params.names[i], params.types[i], original, decoded)) {
+                throw new Error(`Cannot safely encode argument: ${params.names[i]} (${original}) of type ${params.types[i]}. (Possible type overflow or other encoding error)`);
+            }
+        }
+    }
     protected _lookupEthersInterface(functionSignature: string): ethers.Interface {
         const ethersInterface = this._ethersInterfacesByFunctionSignature[functionSignature];
         if (_.isUndefined(ethersInterface)) {
diff --git a/packages/base-contract/test/base_contract_test.ts b/packages/base-contract/test/base_contract_test.ts
new file mode 100644
index 000000000..57aacdc8a
--- /dev/null
+++ b/packages/base-contract/test/base_contract_test.ts
@@ -0,0 +1,110 @@
+import * as chai from 'chai';
+import 'mocha';
+
+import { BaseContract } from '../src';
+
+const { expect } = chai;
+
+describe('BaseContract', () => {
+    describe('strictArgumentEncodingCheck', () => {
+        it('works for simple types', () => {
+            BaseContract.strictArgumentEncodingCheck([{ name: 'to', type: 'address' }], ['0xe834ec434daba538cd1b9fe1582052b880bd7e63']);
+        });
+        it('works for array types', () => {
+            const inputAbi = [{
+                name: 'takerAssetFillAmounts',
+                type: 'uint256[]',
+            }];
+            const args = [
+                [
+                    '9000000000000000000',
+                    '79000000000000000000',
+                    '979000000000000000000',
+                    '7979000000000000000000',
+                ],
+            ];
+            BaseContract.strictArgumentEncodingCheck(inputAbi, args);
+        });
+        it('works for tuple/struct types', () => {
+            const inputAbi = [
+                {
+                    components: [
+                        {
+                            name: 'makerAddress',
+                            type: 'address',
+                        },
+                        {
+                            name: 'takerAddress',
+                            type: 'address',
+                        },
+                        {
+                            name: 'feeRecipientAddress',
+                            type: 'address',
+                        },
+                        {
+                            name: 'senderAddress',
+                            type: 'address',
+                        },
+                        {
+                            name: 'makerAssetAmount',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'takerAssetAmount',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'makerFee',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'takerFee',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'expirationTimeSeconds',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'salt',
+                            type: 'uint256',
+                        },
+                        {
+                            name: 'makerAssetData',
+                            type: 'bytes',
+                        },
+                        {
+                            name: 'takerAssetData',
+                            type: 'bytes',
+                        },
+                    ],
+                    name: 'order',
+                    type: 'tuple',
+                },
+            ];
+            const args = [
+                {
+                    makerAddress: '0x6ecbe1db9ef729cbe972c83fb886247691fb6beb',
+                    takerAddress: '0x0000000000000000000000000000000000000000',
+                    feeRecipientAddress: '0xe834ec434daba538cd1b9fe1582052b880bd7e63',
+                    senderAddress: '0x0000000000000000000000000000000000000000',
+                    makerAssetAmount: '0',
+                    takerAssetAmount: '200000000000000000000',
+                    makerFee: '1000000000000000000',
+                    takerFee: '1000000000000000000',
+                    expirationTimeSeconds: '1532563026',
+                    salt: '59342956082154660870994022243365949771115859664887449740907298019908621891376',
+                    makerAssetData: '0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48',
+                    takerAssetData: '0xf47261b00000000000000000000000001d7022f5b17d2f8b695918fb48fa1089c9f85401',
+                },
+            ];
+            BaseContract.strictArgumentEncodingCheck(inputAbi, args);
+        });
+        it('throws for integer overflows', () => {
+            expect(() => BaseContract.strictArgumentEncodingCheck([{ name: 'amount', type: 'uint8' }], ['256'])).to.throw();
+        });
+        it('throws for fixed byte array overflows', () => {
+            expect(() => BaseContract.strictArgumentEncodingCheck([{ name: 'hash', type: 'bytes8' }], ['0x001122334455667788'])).to.throw();
+        });
+    });
+});