maxPriorityFeePerGas broken on Harmony

[pikeas]

Working under 5.24, seems to be related to the changes introduced by #2205 in 5.25.

[kclowes]

Can you post the error you're seeing?

[pikeas]

It should be reproducible with any call to [contract].functions.[function].transact() - this uses default values, and one of those defaults uses the priority fee RPC call, which fails.

[kclowes]

Got it. So Harmony doesn't support maxPriorityFeePerGas RPC endpoint?

[pikeas]

Got it. So Harmony doesn't support maxPriorityFeePerGas RPC endpoint?

That does seem to be the case. I'm not an expert on Harmony, hopefully someone with more experience can chime in with a definitive answer.

[kclowes]

If they support EIP-1559 style transactions (a.k.a. dynamic fee transactions) but just not the maxPriorityFeeEndpoint, I would try sending in a value for maxPriorityFeePerGas to see if that works. Otherwise the workaround is to manually pass in legacy parameters.

[fselmo]

Harmony isn't expected to work with the eth module out of the box. From a quick glance it looks like using gasPrice is the way to go for Harmony transactions (and this will bypass any calls to max fee endpoints) though you are likely to still run into issues that may need to be built out in order to support Harmony.

We have some ideas in the works to import custom providers / modules in the future but, for now, support for Harmony is not guaranteed. I suggest finding a Harmony developer community or joining the Ethereum Python Community discord as there may be other users out there using Harmony who could help out.

Closing as this is does not look to be an issue with web3.py. Please re-open if you think closing this was in error. Best of luck.

[guoyiteng]

Hi, I'd like to add that eth_maxPriorityFeePerGas isn't part of ETH JSON-RPC spec. It is an endpoint Geth added on its own. Clearly some ETH providers don't have a plan to add it NomicFoundation/hardhat#1664. Maybe using eth_feeHistory is a better idea since it's part of the spec?

Also, it would be great if this can be a built-in middleware so that users could choose between eth_maxPriorityFeePerGas (or eth_feeHistory) and eth_gasPrice based on the chain they want to use.