JSON RPC converter fails to serialise classes from duplicated modules

[spalladino]

The automatic JSON RPC server and client from foundation rely on a ClassConverter object, which requires classes to be (de)serialised to be registered. Classes are indexed by the class object itself.

However, it can be the case that the same classes is loaded from different instances of the same module. We hit this error with PrivateKey: while the type registered in the aztec_rpc_client is exported from the circuits.js, an instance of the PrivateKey from the types package (which re-exports PrivateKey) is the one that gets sent.

aztec-packages/yarn-project/aztec.js/src/aztec_rpc_client/aztec_rpc_client.ts

Line 1 in 94053e4

import { AztecAddress, CompleteAddress, EthAddress, Fr, Point, PrivateKey } from '@aztec/circuits.js';

aztec-packages/yarn-project/aztec.js/src/account/account.ts

Line 2 in 94053e4

import { AztecRPC, CompleteAddress, PrivateKey } from '@aztec/types';

This would be ok if aztec.js and types loaded the same circuits.js from node_modules, but it can be the case that each package keeps its own copy of the dependency. If that happens, they are considered different modules, so each PrivateKey class is not the same. So the lookup in the converter fails.

The end result is that the PrivateKey is serialised incorrectly, so it is deseralised incorrectly on the other side, and the RPC server carries on execution with an incorrect type, which never gets validated because of #1819.