FallbackProvider instantiation fails when providers.length === 1

[jxom]

Ethers Version

6.6.0

Search Terms

No response

Describe the Problem

In v5, you could instantiate a FallbackProvider with only one Provider without the instantiation failing.

However, in v6, when I instantiate a FallbackProvider with only one Provider, the instantiation fails with:

Error: quorum exceed provider wieght (argument="quorum", value=2, code=INVALID_ARGUMENT, version=6.6.0)

(There is also a typo in the above error: "wieght" 🙈)

Is the expected behavior that the FallbackProvider can only be instantiated with greater than one Provider? Or is this a bug?

If this is the expected behavior, might be nice to update the migration guide and maybe make the error message a bit clearer for that case. 🙏

Code Snippet

import { FallbackProvider, JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://cloudflare-eth.com');

const fallbackProvider = new FallbackProvider([provider]); // fails

Contract ABI

No response

Errors

Error: quorum exceed provider wieght (argument="quorum", value=2, code=INVALID_ARGUMENT, version=6.6.0)

Environment

No response

Environment (Other)

No response

[ricmoo]

Thanks! Good catch. This will be fixed with the addition of FallbackProviderOptions to customize the quorum weight. Should come out in the next day or so.

[jxom]

Amazing

[lostadam]

@jxom I also dealt with this (and handled the type in #4149 😅 ) - replaced with this:

  const provider = new FallbackProvider([
    { provider: signer.provider as AbstractProvider, weight: 2 },
  ]);

as the required quorom is 2. Not sure if this will mess with your logic, but allowed me to properly implement by FallbackProvider!

[ricmoo]

That will not affect the logic, but it should have that config exposed since it should be generalized. It’s coming. :p

[ricmoo]

The ability to configure the quorum has been added in v6.7.0, as well as the default being half the total configured weight (ceiling).

When using getDefaultProvider, the default for testnets is 1 and for all other networks it is 2, unless overridden by passing quorum into the options.

Let me know if you have any further issues!

Thanks! :)