web3py issue on Avalanche when using maxPriorityFeePerGas and maxFeePerGas

Question

I'm trying to execute a contract call and set up the gas manually as the gas estimation is not working properly and is setting the gas too low. To do this I modified my send function to include this:

def send_txn(tx):
    """Very simple transaction function that returns the hash and the logs from the receipt after getting it back, hopefully within 60 seconds"""
    tx['nonce'] = w3.eth.getTransactionCount(me)
    tx['chainId'] = chain_id
    #try:
    #    gasr = requests.get("https://api.debank.com/chain/gas_price_dict_v2?chain=avax",timeout=5)
    #    maxPriorityFeePerGas = int(gasr.json()['data']['fast']['price'])
    #    tx['maxPriorityFeePerGas'] = Web3.toWei('2.5', 'gwei')
    #    tx['maxFeePerGas'] = int(maxPriorityFeePerGas)+10*(10**9)
    #    tx['gas'] = 1000000
    #except:
    #    print("Error setting gas")
    signed = w3.eth.account.sign_transaction(tx, private_key)
    txhash = Web3.toHex(w3.eth.send_raw_transaction(signed.rawTransaction))
    receipt = w3.eth.wait_for_transaction_receipt(txhash, timeout=120)
    return txhash, receipt['logs']

So I'm setting miner fee to 2.5 and max fee to whatever Debank's API returns + 10. I then call this function this way:

try:
 txn = contract.functions.mint(me,2).buildTransaction()
 hash, logs = send_txn(txn)
 print(timenow + " - Minted")
except Exception as e:
 print(f"Something broke with mint: {e}")

When that runs it seems to fail and enter the external except and it prints this error: Unknown kwargs: ['gasPrice']

Any idea what might be wrong?

Answer 1

I figured it out.

buildTransaction() creates a dictionary with a gasPrice key only. Apparently that conflicts if maxFeePerGas and maxPriorityFeePerGas are present, so I popped that key out in my gas code and it seems to work.