ERC827代币transferFrom函数在Web3中测试遇revert异常求助

Hey there! Let's dig into why your transferFrom() call (using user1 to invoke your test contract via ERC827) is hitting a revert—especially since other tests for both contracts are working fine. Here are the key areas to check:

1. Verify ERC20 Allowance for user1 #

Even though address a2 holds 10 tokens, ERC827's transferFrom() relies on the standard ERC20 authorization model. Make sure:

• User1 has been properly approved by a2 to spend the required token amount. You can confirm this by checking await token.allowance(a2, user1) in your test setup—this value needs to be >= the amount you're trying to transfer.
• If the allowance is missing or too low, add a step where a2 calls approve(user1, amount) before the transferFrom test. For example:

  await token.connect(a2).approve(user1, 10);
  const allowance = await token.allowance(a2, user1);
  expect(allowance).to.equal(10);
  

2. Check Test Contract's tokenReceived() Implementation #

ERC827 requires that contract recipients implement the tokenReceived() function to handle post-transfer logic. If your test contract is missing this or has an incorrect implementation, the transaction will revert:

• Ensure the function signature matches exactly:

  function tokenReceived(address _from, address _to, uint256 _value, bytes calldata _data) external returns (bytes4) {
      // Your custom logic here
      return bytes4(keccak256("tokenReceived(address,address,uint256,bytes)"));
  }
  

• The return value is critical—if you don't return the correct function selector, the ERC827 contract will trigger a revert. Even if your logic works, skipping this return value will break the flow.

3. Validate the _data Parameter Encoding #

The _data parameter is used to encode the function call for your test contract. A mistake here will cause the test contract to fail, which propagates back as a revert in transferFrom():

• Double-check that you're encoding the function call correctly. For example, if you're calling testFunction(uint256 x) on the test contract, _data should be:

  const data = testContract.interface.encodeFunctionData("testFunction", [5]);
  

• Test the encoded _data directly by calling the test contract's function without going through ERC827. If that call fails, the issue is with the test contract function or encoding, not the ERC827 transfer.

4. Ensure Sufficient Gas is Allocated #

ERC827's transferFrom() does two things: transfers tokens and executes a contract call. This uses more gas than a standard ERC20 transfer. If your test sets a low gas limit, you might hit an out-of-gas error (which shows up as a revert):

• Try increasing the gas limit explicitly when making the transferFrom call. For example:

  await token.connect(user1).transferFrom(a2, testContract.address, 10, data, { gas: 1_000_000 });
  

• Adjust the gas value based on your contract's actual requirements—you can estimate it first with await token.connect(user1).estimateGas.transferFrom(...).

5. Double-Check ERC827 Contract Logic #

Even if other tests pass, verify that your ERC827's transferFrom() implementation correctly handles contract recipients:

• Ensure that after transferring tokens, the contract properly calls the recipient's tokenReceived() function and checks the return value. Some implementations skip this check for regular addresses but enforce it for contracts—if your test contract is a contract address, this check must pass.

内容的提问来源于stack exchange，提问作者user1756501