Help: I cannot calculate the transaction hash

[skolliecool]

Hi All

I have this transaction:

const tx = {
  "hash": "0xf4584008cc70f2f532765a2f035a2525992a258b2d2afd6b49ad5b2857a6197d",
  "type": 2,
  "accessList": null,
  "blockHash": null,
  "blockNumber": null,
  "transactionIndex": null,
  "confirmations": 0,
  "from": "0x0936c90c59ecb79fc01C780f283CABfB9e118940",
  "gasPrice": {
    "_hex": "0x203f403384",
    "_isBigNumber": true
  },
  "gasLimit": {
    "_hex": "0xb41d",
    "_isBigNumber": true
  },
  "to": "0xdAC17F958D2ee523a2206206994597C13D831ec7",
  "value": {
    "_hex": "0x00",
    "_isBigNumber": true
  },
  "nonce": 38,
  "data": "0xa9059cbb0000000000000000000000009418bfc542817e4320480990f34951351b0db5130000000000000000000000000000000000000000000000000000000002faf080",
  "r": "0x270e826d5bbf71fa492de0da460b06f0f586d007d05db364493d1bf70b4fc77e",
  "s": "0x4b4795d7c50cd4e56342ab3044cb3986f85278a4a2377dcc621589d8289bfaaf",
  "v": 1,
  "creates": null,
  "chainId": 0
};

The transaction hash, 0xf4584008cc70f2f532765a2f035a2525992a258b2d2afd6b49ad5b2857a6197d can be seen on etherscan - so the values above correspond to what is on Etherscan.

However, there is no way I am able to calculate this hash using ethersjs. Here is how I have tried:

METHOD 1 - use get raw transaction from the cookbook

getRawTransaction(tx); // Exception, since hashes don't  equal

METHOD 2 - serialize and calculate myself (this turns out to be identical to the above method, but I will include it anyways)

const st = utils.serializeTransaction(tx, {r,s,v});
console.log(tx.hash === utils.keccak256(st)); // false 

METHOD 3 - maybe BigNumber should be converted to string???

const newTx = {
  data: '0xa9059cbb0000000000000000000000009418bfc542817e4320480990f34951351b0db5130000000000000000000000000000000000000000000000000000000002faf080',
  gasPrice: BigNumber.from('0x203f403384').toString(),
  gasLimit: BigNumber.from('0xb41d').toString(),
  nonce: 38,
  to: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
  type: 2,
  value: BigNumber.from('0x00').toString(),
  "r": "0x270e826d5bbf71fa492de0da460b06f0f586d007d05db364493d1bf70b4fc77e",
  "s": "0x4b4795d7c50cd4e56342ab3044cb3986f85278a4a2377dcc621589d8289bfaaf",
  "v": 1,
}

const st = utils.serializeTransaction(newTx, {r,s,v});
console.log(tx.hash === utils.keccak256(st)); // false - actually, false hash is identical to ones above 

The only thing I can think of is that the "r", "s" and "v" values may have changed (which I think is impossible). Or, I am doing something wrong (which is far more possible).

Any help would be appreciated.

[merklefruit]

More than 6 months passed since this question was asked, but I figured this could be helpful to others maybe.

You should check this out. Hope it helps!

[gradaom]

I usually use web3.js more than ethers.js .

We can easily calculate Hash using web3.js and it will help you.

myContract.methods.myMethod(123).send({from: '***address***'})
    .on('transactionHash', function(hash){
        console.log(hash);
})

[ricmoo]

This question was more about recomputing the hash for a historic transaction already on chain. If you send a transaction in ethers, you can use (await myContract.myMethod()).hash.

FYI. For those using v6, for recomputing historic hash you can use instead use Transaction.from(tx).hash. It will validate all provided properties for you, use default for missing values and throw if there are inconsistent values. :)