How to generate a burn proof?

[CodeSandwich]

Hi! I'm trying to generate a burn proof for PoS bridge ERC-20 withdrawal from Mumbai.

Here's my burn TX: https://mumbai.polygonscan.com/tx/0xb580d143c27e98d13a5b54e3f432c4ce5e6e5c72c2ba5733d1b4175cec1da397 It's a smart contract call initiated by an incoming FX portal message, which burns some ERC-20 tokens. I've been trying to generate the burn proof with this code:

const Matic = require("@maticnetwork/maticjs").default;
const matic = new Matic({
  maticProvider: "https://rpc-mumbai.matic.today",
  parentProvider: "https://goerli.infura.io/v3/75aa7935112647bc8cc49d20beafa189",
});
const exit_manager = matic.withdrawManager.exitManager;
const BURN_HASH = '0x3f8a6e175862601408288ecc5032b8f8b94b187ebc4eb82e744456c9bd3379c6';
const SIG = '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef';
const proof = await exit_manager.buildPayloadForExitHermoine(BURN_HASH, SIG);
console.log("Burn proof:", proof);

Unfortunately I'm getting an error:

(node:2404637) UnhandledPromiseRejectionWarning: Error: Node does not contain the key
    at /home/zuczek/node_modules/@maticnetwork/maticjs/dist/webpack:/src/libs/ProofsUtil.ts:424:1
    at /home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:461:14
    at Object.return (/home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:485:9)
    at processNode (/home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:288:30)
    at processNode (/home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:521:5)
    at /home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:457:5
    at /home/zuczek/node_modules/merkle-patricia-tree/baseTrie.js:180:7
    at processTicksAndRejections (internal/process/task_queues.js:75:11)

I've tried exit_manager.buildPayloadForExit and exit_manager.getExitHash, but they generate exactly the same error.

[Dimfred]

Were you able to resolve your issue? I have the exact same code + error. Tho I am using fxportals.

[ujjwalgupta94]

@Dimfred are you using maticjs-fxportal ?

[Dimfred]

Yes I do. So the interesting thing is I withdrew another ERC721 today, and the second one went through. Tho, I used withdrawTo in the fxportal example contract and not withdraw, but the popped event should be the same / same signature.

So idk what happened with the first one, but I guess it's stuck now. I hope this doesn't happen on mainnet.

[ujjwalgupta94]

I can not say from here, but might be you did something wrong in first tx. Anyway try with multiple tx and see how it goes. Let me know if there is any issue.

[Dimfred]

Can't be that I did something wrong in the first tx, cause I did exactly the same in the second. But yeah as said it worked in the second so I guess it's fine.

[asselstine]

Here is an updated script:

https://gist.github.com/asselstine/37429e42fcb9807dbfcde9a6376be5d4