'ERC20: insufficient allowance' (again)

Smart Contracts
1

I've checked this so many times, also went back to my older codes (that works), I do not understand why this is giving an allowance of zero. I've been stuck all day, what did I miss here?

const approve = await usdc.approve(contract.address, 1000); 
const numAllw = await usdc.allowance(user1.address, contract.address);
console.log(numAllow) // is zero

I know increaseAllowance can just performed both, but my returned allowance is still zero.
await usdc.connect(user1).increaseAllowance(user1.address, contract.address);

await contract.connect(user1).doStuff(1000)

contract Contract {
   ///...
  function doStuff(uint amount)  public returns (bool) {
        // user send usdc
        USDC.transferFrom(msg.sender, address(this), amount);
        emit SendUSDC(msg.sender, amount);
  }
}

reverted with reason string 'ERC20: insufficient allowance'

2

It should work so something you are doing isn’t correct, however without posting the exact code and transaction it’s hard to say what.

There approve function should return a true or false value telling you if it succeeded. Maybe the Usdc address is incorrect or different between you client side and Usdc address set in your contract?

3

Just checked, it returns true on approved.
Also checked usdc totalSupply calling from the contract, also returned a value. So the usdc address isn't incorrect.

This is all strange now :confused: . But thanks, it gives me some direction to debug into.

4

I think it is zero, cause you do not connect your account, maybe it should be

const approve = await usdc.connect(user1).approve(contract.address, 1000);

And for the function increaseAllowance(), I think it should be

function increaseAllowance(address spender, uint256 addedValue)

So you need pass an address and amount rather than two addresses.