Event log decode fails

[viswanathkgp12]

I've tried decoding OracleRequest event logs from this tx using web3.eth.abi.decodeLog

Expected behavior

Decodes correctly to:

Result {                                                                                                                                                                                                                                                                                                        
  requester: '0x9745936F56296f557B089F77ccb55d582A1a37ee',                                                                                                              
  requestId: '0xd0b9a398aae63b33fad8b98f42ddf483f6626c647e90bef4fe94a9425db8a29e',                                                                                      
  payment: '100000000000000000',                                                                                                                                        
  callbackAddr: '0x9745936F56296f557B089F77ccb55d582A1a37ee',                                                                                                           
  callbackFunctionId: '0x7f78fc7a',                                                                                                                                     
  cancelExpiration: '1597179626',                                                                                                                                       
  dataVersion: '1',                                                                                                                                                     
  data: '0x63676574782b68747470733a2f2f626c6f636b636861696e2e696e666f2f7469636b65723f63757272656e63793d5553446470617468685553442e6c6173746574696d65731b0de0b6b3a7640000'
,                                                                                                                                                                       
  specId: '0x6632393166383539376431373466346161313938336230653237616531363066'                                                                                          
}                                                                                                                                                                       

Actual behavior

Event log decode fails. Logs attached below.

From the logs, it looked like the abi decoder expects event data to be a multiple of 32 bytes or 64 hex characters. When I padded extra zeroes at the end to satisfy this condition, it decoded correctly. I think the library should handle this automatically.

Steps to reproduce the behavior

const Web3 = require("web3");
const web3 = new Web3("https://cloudflare-eth.com");

// This can be cross-verified from the below link
// https://etherscan.io/address/0x89f70fa9f439dbd0a1bc22a09befc56ada04d9b4#code
const oracleRequestEventLogInputsABI = [
  {
    name: "requester",
    type: "address",
  },
  {
    name: "requestId",
    type: "bytes32",
  },
  {
    name: "payment",
    type: "uint256",
  },
  {
    name: "callbackAddr",
    type: "address",
  },
  {
    name: "callbackFunctionId",
    type: "bytes4",
  },
  {
    name: "cancelExpiration",
    type: "uint256",
  },
  {
    name: "dataVersion",
    type: "uint256",
  },
  {
    name: "data",
    type: "bytes",
  },
  {
    indexed: true,
    name: "specId",
    type: "bytes32",
  },
];

async function testEventLogDecode() {
  const { logs } = await web3.eth.getTransactionReceipt(
    "0x2e2aec5cbd5bff2c720dd1387a692c1f2ec691f996e6edb8518c7125d1bab2e5"
  );

  // OracleRequest Event log is at index 7 - HARDCODED
  const oracleRequestEventLogData = logs[7].data;
  const oracleRequestEventLogTopics = logs[7].topics;

  // This data can be cross-checked from etherscan
  // https://etherscan.io/tx/0x2e2aec5cbd5bff2c720dd1387a692c1f2ec691f996e6edb8518c7125d1bab2e5#eventlog
  console.log("Oracle Request eventLogData: ", oracleRequestEventLogData);
  console.log("Oracle Request topics: ", oracleRequestEventLogTopics);

  // Remove topic[0]
  // https://web3js.readthedocs.io/en/v1.2.11/web3-eth-abi.html#decodelog
  oracleRequestEventLogTopics.shift();

  const result = web3.eth.abi.decodeLog(
    oracleRequestEventLogInputsABI,
    oracleRequestEventLogData,
    oracleRequestEventLogTopics
  );

  console.log("Decoded data: ", result);
}

testEventLogDecode();

Logs

(node:2280) UnhandledPromiseRejectionWarning: Error: data out-of-bounds (length=127, offset=128, code=BUFFER_OVERRUN, version=abi/5.0.0-beta.153)
    at Logger.makeError (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\logger\lib\index.js:179:21)
    at Logger.throwError (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\logger\lib\index.js:188:20)
    at Reader._peekBytes (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\abstract-coder.js:135:20)
    at Reader.readBytes (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\abstract-coder.js:146:26)
    at BytesCoder.DynamicBytesCoder.decode (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\bytes.js:30:23)
    at BytesCoder.decode (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\bytes.js:41:81)
    at C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\array.js:77:31
    at Array.forEach (<anonymous>)
    at Object.unpack (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\array.js:71:12)
    at TupleCoder.decode (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\coders\tuple.js:39:49)
    at AbiCoder.decode (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\@ethersproject\abi\lib\abi-coder.js:93:22)
    at ABICoder.decodeParameters (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\web3-eth-abi\src\index.js:341:30)
    at ABICoder.decodeLog (C:\Users\dell\Desktop\matic-security-hackathon\node_modules\web3-eth-abi\src\index.js:395:52)
    at testEventLogDecode (C:\Users\dell\Desktop\matic-security-hackathon\test.js:64:31)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)

Environment

Tested on web3js v1.2.9 and v1.2.11

[ryanio]

Please see related issue: #3544

from ethers-io/ethers.js#992 (comment):

There is a known Solidity v4.x bug that events emitted from an external (public is fine) function in Solidity that dynamic objects are encoded incorrectly.
This is a compiler bug which makes it very hard to work around. :(
The work around for it can break correctly functioning contracts, which is the problem.

[viswanathkgp12]

Okay. I didn't see that. Since there is another issue open reg. the same, should I close this?

[GregTheGreek]

@viswanathkgp12 We'll keep it open for now, its a good reference point.

[ricmoo]

I've added support in ethers 5.0.12 for supporting legacy Solidity 0.4 external event data. I believe web3 depends on the abi package directly, in which case web3 should upgrade to @ethersproject/abi version 5.0.4.

For more details, please see ethers-io/ethers.js#891.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions. If you believe this was a mistake, please comment.

[GregTheGreek]

@koraykoska Can you double check this :)

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions. If you believe this was a mistake, please comment.

[koraykoska]

@ethersproject/abi is on 5.0.7 and this issue shouldn't exist any more.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions. If you believe this was a mistake, please comment.