Hardcoded priority fee causes txs on Polygon to fail

[wschwab]

Ethers Version

5.7.1

Search Terms

priority fee, polygon, gas estimation

Describe the Problem

Ethers currently hardcodes the priority fee, where applicable, at 1.5 gwei: source

This creates a quandary on Polygon's main chain, since there is an enforced minimum 30 gwei priority fee there. (I'm looking for a source I can link, though I have confirmed this with Polygon. Update: I still don't have a link to docs or something like this, but here is an announcement on an official forum.) This is probably why users are experiencing issues submitting txs on Polygon: issue

I wasn't sure if this should be called a feature request or a bug, and opted for bug, since the functionality of gas estimation isn't working as expected on a major chain.

fwiw, hardcoding 30 gwei priority is way too high for Ethereum, but would it possible to make a ternary that checks if network.chainId is 137 (Polygon main), and if not, use 1.5, and if yes, 30? Something like:

maxPriorityFeePerGas = network.chainId !== 137 ? BigNumber.from("1500000000") : BigNumber.from("30000000000");

(I mean that more for illustrative purposes than as actual code.)

Thanks for reading!

Code Snippet

// copied from the issue linked above
// assumes network.chainId === 137

signer.populateTransaction(txParams)
signer.sendTransaction(txParams)

Contract ABI

No response

Errors

\"message\":\"transaction underpriced\"

Environment

Polygon

Environment (Other)

n/a

[ZeroEkkusu]

In case it is helpful for investigation, foundry-rs/foundry#3368 is not merged yet, but it fixes the issue in Foundry/ethers-rs by handling Polygon separately.

[pcaversaccio]

any update on this issue @ricmoo? It impacts the users for my hardhat plugin xdeployer directly - see the discussion here: pcaversaccio/xdeployer#53.

[ricmoo]

This is a known issue with BSC/Polygon, since they do not correctly implement the EIP-1559 standard.

Unfortunately for those networks, it is necessary to use a gas station (much like Ethereum did prior to EIP-1559). There isn't really a way to get good data (especially during times of congestion) from the blockchain directly.

My best advice would be that someone creates a sub-class of Signer, and overrides the getFeeData method to use a gas station instead. This is one reason why getFeeData is present there. :)

If someone creates a sub-class of Signer, let me know and I'll link to it from the docs. But I don't know there is much that ethers can do directly.

Closing for now, but please feel free to continue commenting. I monitor closed issues. :)

[sambacha]

This is a known issue with BSC/Polygon, since they do not correctly implement the EIP-1559 standard.

Unfortunately for those networks, it is necessary to use a gas station (much like Ethereum did prior to EIP-1559). There isn't really a way to get good data (especially during times of congestion) from the blockchain directly.

My best advice would be that someone creates a sub-class of Signer, and overrides the getFeeData method to use a gas station instead. This is one reason why getFeeData is present there. :)

If someone creates a sub-class of Signer, let me know and I'll link to it from the docs. But I don't know there is much that ethers can do directly.

Closing for now, but please feel free to continue commenting. I monitor closed issues. :)

What do you think of this approach: Synthetixio/js-monorepo#915

Uses a Moving Avg. for deriving priority fee. Not sure how good the rest of the implementation is for gas pricing though the approach for deriving a priority fee using only block information is portable across chains (YMMV).

Thanks @ricmoo

[ricmoo]

So, I think you need to use a gas station to get accurate pricing information. If there is an official gas station or you can get polygon in touch with me, I’ve considered making a custom Network for Polygon, which would support a gas station for gas pricing. :)

[ricmoo]

(Oh, and it only affects networks like Polygon and BNB; other networks which capitalize on EIP-1559 economic incentives already work out of the box ;))

[pcaversaccio]

So, I think you need to use a gas station to get accurate pricing information. If there is an official gas station or you can get polygon in touch with me, I’ve considered making a custom Network for Polygon, which would support a gas station for gas pricing. :)

@wschwab is from Polygon ;)

[wschwab]

@ricmoo I'd be happy to help however I can