How to detect failure of contract deployment?

[emclab]

My React Native (0.64) uses ethers (5.4.6) to deploy contract. The current code can handle when deploy throws an error and success by using try catch and listening to event. However if the deployment has failed, how to detect the failure?

Here is the code:

try {

            const factory = new ContractFactory(abi, bytecode, _wallet); //wallet is signer
            
            contractFS = await factory.deploy(value, item.name, item.id); //<<==how to detect deploy failure?
            contractFS.on("itemForSale", async (myBCAddress, itemName, itemId, event) => {. //<<== listen to 'ItemForSale" event
                 //.......
            }
} catch (err) {
  //process error 
}

[zemse]

You can get the deploy transaction and check its success:

const contractFS = await factory.deploy(value, item.name, item.id);
const tx = contractFS.deployTransaction
const receipt = await provider.getTransactionReceipt(tx.hash);
receipt.success // false means the deploy tx failed, due to some sort of revert.

There can be other reasons for deploy failure like network failure, seems that it will be caught in your try/catch.

[emclab]

Hi zemse, the app used to only execute factory.deploy() and listens to the contract event? What is the contractFS returned by factory.deploy()? Is there any error message with contractFS if deploy fails?

[zemse]

What is the contractFS returned by factory.deploy()?

Return value of factory.deploy() is the contract instance, I think you already know that looking from your code, do you mean to ask something else?

Is there any error message with contractFS if deploy fails?

What kind of errors are is the application catching? And what kind of failures do you anticipate? Insufficient funds / network failure? I believe the factory.deploy promise rejects if the transaction is failed, i.e. contractFS is not resolved by the promise.

[emclab]

I don't quite understand why the return of contract instance will not signal deployment failure if there is one.

I want to add code to catch the failure of contract deployment. The current code of my app has no way to react to tx failure (here the failure is contract deployment, such as bad params, condition not met) other than listen to event of success.

[zemse]

bad params, condition not met

These things trigger an error, which you should be able to catch. Also in such case your contractFS will not be set. So if it was not set then it went to an error.

contractFS = await factory.deploy(...) // if this errors contractFS will not be set