Getting the addresses of 2 contracts which are deployed with 1 function call.

[swan-of-bodom]

Normally I interact with contract deployments like:

Method 1:

let Contract = await ethers.getContractFactory("ExampleContract");
let contract = await Contract.deploy( /* constructor args */ );

This works fine when only 1 "ExampleContract" is deployed. But in the case that there is a function that deploys 2 contracts, what would be a work around? For example, imagine I have 1 LP Token and want to deploy 2 contracts that represent token0 and token1 with:

function deployContracts(lpTokenAddress) { 
    deploys first contract representing Token A;

    deploys second contract representing Token B;
}

The reason I am asking this is because I believe there might be unexpected behaviour in regards to custom errors introduced in Sol 0.8.4.

Since I wrote the 2 contracts that would be deployed, the work around I implemented was to deploy the 2 contracts with the 1 function from above but this time store token0 and token1 deployed addresses in a mapping (lpToken => struct) to then get them with ethers:

Method 2:

token0Factory = await ethers.getContractFactory(token0);
token1Factory = await ethers.getContractFactory(token1);

deployedToken0 = await token0Factory.attach(mapping[lpToken].token0);
deployedToken1 = await token1Factory.attach(mapping[lpToken].token1);

Now the problem is that when I run tests on the contracts with waffle, they behave correctly, but without showing any custom errors. All error messages show as:

AssertionError: Expected transaction to be reverted with { reason }, but other exception was thrown: ProviderError: VM Exception while processing transaction: revert with unrecognized return data or custom error

If I deploy and test the contracts with Method 1, they show all custom errors correctly. Using method 2, they revert when they should, but it seems as if the errors in the interfaces aren't getting recognized... Surprisingly, events aren't affected though.

Is this a problem of the custom reverts feature?

Any ideas on a work around to get the contract object when it is deployed from another contract's methods (such as a Uniswap Factory which deploys 2 contracts for example)?

Thanks!

[zemse]

Any ideas on a work around to get the contract object when it is deployed from another contract's methods (such as a Uniswap Factory which deploys 2 contracts for example)?

In your contract, you can emit an event after the deployment and on the client-side get the transaction receipt to see the event logs in it. Since this is much cheaper than a storage write, it is the preferred way than being just a workaround, the whole purpose of events is to emit some data for external things instead of using the costly storage + function call. Uniswap emits a Pool Created event as well (and I think they also store it on the storage for the convenience of some devs).

[zemse]

AssertionError: Expected transaction to be reverted with { reason }, but other exception was thrown: ProviderError: VM Exception while processing transaction: revert with unrecognized return data or custom error

About this one, I can see this error on a number of threads after hardhat released a new version (one of them: #2849 (comment)).

[swan-of-bodom]

I was looking to avoid using the contract.attach method since I thought that's where my issue was coming from. My logic was that there was a difference somewhere in object b between these 2 methods:

method 1:

let a = await ethers.getContractFactory('name')
let b = await a.deploy()

now i can interact with b normally.

method 2:

previously deploy 'name' and do

let a  = await ethers.getContractFactory('name')
let b = await a.attach('name'.address)

now i can interact with contract b.

However my original assumption was that the b object in both cases differ somehow and that was the reason i couldn't get the revertedWith method to work correctly (all those deployed with method 1 worked fine, all those deployed with method 2 did not).

After giving up and moving on, i eventually deleted node_modules while working on something else and updated from @nomiclabs/hardhat-ethers ^2.0.5 to @nomiclabs/hardhat-ethers ^2.0.6 and reinstalled packages. I ran the tests again on the same file without any modifications and i can now finally see revert reasons. Anyways hope it helps someone

[zemse]

Method 2 cannot work since it has 'name'.address and .address is available on ethers.Contract objects and not strings. In your method 1 snippet, a is an instance of the ethers.ContractFactory class and b is a deployment of it, an instance of ethers.Contract.

let AppleFactory = await ethers.getContractFactory('Apple')
let apple = await a.deploy()
// now you can interact with apple

The .attach is used when you already have the contract deployed somewhere and just want to use that address.

const addressOfContract = '0x1234...'
let AppleFactory = await ethers.getContractFactory('Apple')
let apple = AppleFactory.attach(addressOfContract);