Transaction Reverted when attempting to withdraw from aave

Question

I got an example running which deposits the Aave token into Aave. I'm using the Code Contracts examples provided by Aave v2 github

// Fork Kovan
await hre.network.provider.request({
    method: 'hardhat_reset',
    params: [{ forking: { jsonRpcUrl: KOVAN_JSON_RPC } }],
});

// Act like AAVE_HOLDER
await hre.network.provider.request({
    method: 'hardhat_impersonateAccount',
    params: [AAVE_HOLDER],
});
const signer = await hre.ethers.getSigner(AAVE_HOLDER);
console.log('signer:', signer.address);

// AAVE token on Kovan network
const aavetoken = IERC20__factory.connect(AAVE_TOKEN_ADDRESS, signer);
console.log('token balance:', (await aavetoken.balanceOf(signer.address)).toString());

const MyV2CreditDelegation = new MyV2CreditDelegation__factory(signer);
const delegation = await MyV2CreditDelegation.deploy({ gasLimit: 1e7 });
console.log('delegation:', delegation.address);

// Set the allowance higher than the deposit amount
// so we know we can make multiple transactions
let allowance = 100000
let despositAmount = 10;

await aavetoken.approve(delegation.address, allowance);
console.log('allowance:', (await aavetoken.allowance(signer.address, delegation.address, { gasLimit: 1e6 })).toString());

const depositTrans = await delegation.depositCollateral(aavetoken.address, despositAmount, true, { gasLimit: 1e6 });
console.log('depositTrans:', depositTrans.hash);
const depositReceipt = await depositTrans.wait();

Deposit works fine, However when I try to withdraw:

try  {
    var withdrawTrans = await delegation
        .withdrawCollateral(aavetoken.address,  { gasLimit: 1e6 })

    console.log('withdrawTrans:', withdrawTrans.hash);
    const withdrawReceipt = await withdrawTrans.wait();
}
catch (err) {
    console.log('Error:' + err);
}

I get an error:

Transaction reverted: function returned an unexpected amount of data

I'm pretty new to hardhat, I'm now sure of how to debug this any further. How can I withdraw from Aave?

Answer 1

I had the same error

Transaction reverted: function returned an unexpected amount of data

This happened when i called a function on an external contract that returns bytes32 and i assigned the return value to a variable of type bytes.

Contract1

    function Func1() external returns (bytes memory returnValue) {   
        returnValue = Contract2(contract2.address).Func2();
      }

On another Contract2

bytes32 Var = 0x5d73888975b842f81b854bb06846b539e34142cbcd3cc5e5e7ec53bafb8ed151;

    function Func2() external returns (bytes32 returnValue) {   
        return Var(;
      }