Can't call existing Solidity function with Brownie due AttributeError

Question

I have deployed a simple contract on the BSC testnet which has a simple function that executes a swap on Pancakeswap.

This is how I call the function with Brownie:

def main():
    tx = contract1.buyToken(0.01,10000,'0x094616F0BdFB0b526bD735Bf66Eca0Ad254ca81F','0xC880a918eDB02E9cf006369927a68c5e7F778B4B')
    return True

And I get this error:

Running '\python_projects\docs3\coin_observer\brownie\scripts\testz.py::main'...
  File "c:\users\home\appdata\roaming\python\python38\lib\site-packages\brownie\_cli\run.py", line 50, in main
    return_value, frame = run(
  File "c:\users\home\appdata\roaming\python\python38\lib\site-packages\brownie\project\scripts.py", line 103, in run
    return_value = f_locals[method_name](*args, **kwargs)
  File "\python_projects\docs3\coin_observer\brownie\scripts\testz.py", line 7, in main
    tx = contract1.buyToken(0.01,10000,'0x094616F0BdFB0b526bD735Bf66Eca0Ad254ca81F','0xC880a918eDB02E9cf006369927a68c5e7F778B4B')
AttributeError: 'ContractContainer' object has no attribute 'buyToken'

And here is the Solidity part:

function buyToken(uint amountToSpend, uint amountToBuy, address tokenToSpendAddress, address tokenToBuyAddress) public returns (uint[] memory amounts)  {
    require(address(this).balance > amountToSpend);
    uint256[] memory receivedTokens;
    address[] memory path = new address[](2);
    path[0] = tokenToSpendAddress;
    path[1] = tokenToBuyAddress;
    receivedTokens = _pancakeRouter.swapExactETHForTokens{value: amountToSpend}(amountToBuy,path,address(this),block.timestamp + 30); 
    return receivedTokens;
}

So my problem is why I get the object has no attribute 'buyToken' error? The buyToken exists in the contract and it compiled correctly.

UPDATE I compiled and deployed the contract again and printed the ABI that seems fine, it contains the function, but the error still exists. I assume something with the ContractContainer is wrong.

Answer 1

In your brownie script you need to specify the value you want to send with that transaction.

so

def main():
    tx = contract1.buyToken(0.01,10000,'0x094616F0BdFB0b526bD735Bf66Eca0Ad254ca81F','0xC880a918eDB02E9cf006369927a68c5e7F778B4B', {"from": account, "value": 10})
    return True

The value should match the amount you pass to the contract. Hope this helps.

Answer 2

I had a same error. The problem was in variable. I accidently write MainContract insted of main_contract. MainContract was a storage of compiled contracts and main_contract is deployed contract