bug with method buildTransaction in the version 5.25.0

[AHTOH2001]

• Version: 5.25.0
• Python: 3.9.7
• OS: linux/win

What is wrong?

The buildTransaction method without specifying gasPrice raises ValueError {'code': -32601, 'message': 'the method eth_maxPriorityFeePerGas does not exist/is not available'}

Snippet to reproduce the issue

from web3 import Web3
import json

web3 = Web3(Web3.HTTPProvider("..."))
# Any ERC-20 contract
contract_addr = '...'
from_addr = '...'
to_addr = '...'

with open('abi.json', 'r') as fp:
    abi = json.load(fp)

contract = web3.eth.contract(contract_addr, abi=abi)

nonce = web3.eth.get_transaction_count(from_addr)
transaction = contract.functions.transfer(
    to_addr,
    web3.toWei(0.1, 'ether')
)
transaction = transaction.buildTransaction({
    'from': from_addr,
    'chainId': 56,
    'nonce': nonce,    
    # 'gasPrice': web3.toWei(5, 'gwei')
})

How can it be fixed?

• Use previous version 5.24.0 in which it was working perfectly
• Specify explicitly the gas price

[fselmo]

@AHTOH2001, thanks for reaching out. Ethereum transactions now default to the most efficient transaction type if the user does not provide fee values (gasPrice or max*FeePerGas fee values). This means it defaults to using maxFeePerGas and maxPriorityFeePerGas, opting for a dynamic fee transaction (type=2) over a legacy transaction.

What's going on here that is not ideal is that, currently, there is a geth-centric default in using eth_maxPriorityFeePerGas. Since this method is not on the Ethereum JSON-RPC specs, it shouldn't be expected to be implemented on all clients. We will be changing this in order to make the default value more flexible across different providers and that is being tracked here.

I'm assuming if you need to use gasPrice that your are either using a layer 2 provider or a provider for another chain that is not Ethereum. If so, this method is bound to the eth module, via the eth.contract utilities, so this would not be a bug. We recently added support for attaching external modules and this feature could be used to attach layer 2 (ideally coming soon) or alternate chain modules when those become available as well.

What happens when you provide a gasPrice is you override the dynamic fee transaction default that was in place, opting for a legacy transaction (which is less efficient in Ethereum), and it should work just as it did before.

I'm going to close this but if you feel like there is a bug here that hasn't been addressed, please feel free to reopen this issue.

[AHTOH2001]

Yea, you are right, I'm using bsc network with quick node provider, the reason why I think this is a bug is that using the same provider at the library version 5.25.0 it raises exception, although at the version 5.24.0 it works fine.

[AHTOH2001]

And unfortunately I cannot re-open my own issue if a repo collaborator closed it.

[fselmo]

Please re-read my comment above. If using gasPrice explicitly works, this is how you will have to use the eth module on bsc. If it was the bsc module, this would be a bug. Best of luck.

[mikke555]

I'm getting this warning when sending EIP-1559 style transaction over zkSync network:

.venv\lib\site-packages\web3\eth\eth.py:186: UserWarning: There was an issue with the method eth_maxPriorityFeePerGas. Calculating using eth_feeHistory

What would be the correct way if not using gasPrice?

[fselmo]

I'm getting this warning when sending EIP-1559 style transaction over zkSync network:

.venv\lib\site-packages\web3\eth\eth.py:186: UserWarning: There was an issue with the method eth_maxPriorityFeePerGas. Calculating using eth_feeHistory

What would be the correct way if not using gasPrice?

This warning happens when either maxPriorityFeePerGas or maxFeePerGas (or both) are not present in your transaction dictionary when sending a transaction. The in-house default way of calculating EIP-1559 fees is to call eth_maxPriorityFeePerGas to determine the value from the client that's running on whatever node you're connecting to. If that method is not available on the client then the fee is calculated using eth_feeHistory.

If you don't want to see this warning, you have to set your own values for maxFeePerGas and maxPriorityFeePerGas. Hope that helps.