abi/bind: workaround for OpenEthereum missing eth_maxPriorityFeePerGas for Kovan

[shoenseiwaso]

Resolves #23479

go-ethereum as a JSON RPC client may be used to connect to Kovan via OpenEthereum nodes, which do not currently support eth_maxPriorityFeePerGas, used by ethclient.SuggestGasTipCap(). This is called in bind.transact() and we receive a "Method not found" error from OpenEthereum.

In this case, we fall back to the logic suggested in this comment and compute tip = eth_gasPrice - baseFee.

One question is whether we should try to match the error string or just try for it on any error.

Tested on Kovan on both Infura and Alchemy.

Side note that I recently learned OpenEthereum has been deprecated, although I'm sure Kovan will be around for a while. There are probably other nodes that will not implement eth_maxPriorityFeePerGas that would benefit from this. A longer term fix might be to consider something involving eth_feeHistory, although I had a hard time following the various threads around EIP-1559 and what the best approach for this would be. Certainly open to suggestions in this PR.

[rjl493456442]

Originally eth_maxPriorityFeePerGas was a part of standard JSONPRC spec but was abandoned later. We should use feeHistory instead since it's expected to be implemented by all clients.

[shoenseiwaso]

Originally eth_maxPriorityFeePerGas was a part of standard JSONPRC spec but was abandoned later. We should use feeHistory instead since it's expected to be implemented by all clients.

Ok great! I can update the PR to use this.

Do you have a link to how we might use eth_feeHistory instead? I looked around online but it was hard to figure out what the "right" way to do this was.

[ligi]

@zsfelfoldi did this: https://github.com/zsfelfoldi/feehistory - maybe this can be used here?

[shoenseiwaso]

@zsfelfoldi did this: https://github.com/zsfelfoldi/feehistory - maybe this can be used here?

@zsfelfoldi would you consider relicensing this under the LGPL so we can look at it for go-ethereum? (I am not a software licensing expert, just being cautious...)

[MariusVanDerWijden]

Since OpenEthereum is officially deprecated and is not able to sync mainnet anymore, I'll close this PR.
Erigon, Besu and Nethermind all implement eth_maxPriorityFeePerGas afaict