Hard Coded 500000 gas Limit Causing Issues When Bridging to Optimism about hop HOT 6 CLOSED

Gas estimation continues to be an issue on optimism for us. We will likely need to move away from Hop as a result unfortunately

from hop.

The reason for the hardcoded limit is because the transaction fails due to ethers estimating too low (example txs 1, 2).

You can however specify your own gas limit or let ethers estimate it for you. Example:

const { Hop } = require('@hop-protocol/sdk')
const ethers = require('ethers')
require('dotenv').config()

async function main() {
  const hop = new Hop('mainnet')
  const privateKey = process.env.PRIVATE_KEY
  const provider = new ethers.providers.getDefaultProvider('mainnet')
  const signer = new ethers.Wallet(privateKey, provider)
  const bridge = hop.connect(signer).bridge('ETH')

  const txData = await bridge.populateSendTx(ethers.utils.parseUnits('0.01', 18), 'ethereum', 'optimism')

  // txData.gasLimit = 150_000 // your own custom gas limit
  delete txData.gasLimit // let ethers estimate gas limit
  console.log(txData)

  const tx = await signer.sendTransaction(txData)
  console.log(tx)
}

main().catch(console.error)

We're planning on removing the hardcoded value once the rpc providers return a more reliable gas limit for Optimism and Base, since currently it fails with estimated gas limit and users aren't able to perform transfers.

from hop.

I see, thank you for the response--will give this a whirl. Previously we had modified the code to use the gas estimation from populateSendTx but were running into the underestimate of gas limit like you mentioned, interesting that the underlying issue is ethers.

500000 though was too high for us because we were trying to do a full sweep of max native ether, anecdotally 170000 seems to be a more reasonable hardcoded limit at least for OP

from hop.

Even when using the above approach, sending the transaction always fails with:

Error: insufficient funds for intrinsic transaction cost [ See: https://links.ethers.org/v5-errors-INSUFFICIENT_FUNDS ] (error={"rawMessage":"Error forwarded from node: insufficient funds for gas * price + value: balance 3390584819344368, tx cost 8351900601944368, overshot 4961315782600000","code":-32603,"message":"Magic RPC Error: [-32603] Error forwarded from node: insufficient funds for gas * price + value: balance 3390584819344368, tx cost 8351900601944368, overshot 4961315782600000"}, method="sendTransaction", transaction=undefined, code=INSUFFICIENT_FUNDS, version=providers/5.7.0)

When trying to do a full sweep... it seems something about the bridge transaction causes ethers to overestimate the txn cost and return early (before even submitting to the network where it would presumably fail)

from hop.

Actually, once we also specified other gas parameters such as maxFeePerGas and maxPriorityFeePerGas which aligned with our gas estimation it started working.

The issue seemed to be with gas spiking as the txn was submitted.

from hop.

Thanks for the support!

from hop.