bug: deploying a contract with no #[private] methods fails

[wei3erHase]

When trying to create a contract from scratch, started declaring storage and a few public functions (and empty constructor), but when using the same Noir deployment sequence as in the https://github.com/aztecprotocol/aztec-starter/ repo:

pub fn setup() -> (&mut TestEnvironment, AztecAddress, AztecAddress) {
    let mut env = unsafe { TestEnvironment::new() };

    let admin = unsafe { env.create_account() };

    let initializer_call_interface = MyContract::interface().constructor();
    let voting_contract = unsafe {
            env.deploy_self("MyContract").with_public_void_initializer(initializer_call_interface)
        };
    std::println(voting_contract);
    (&mut env, voting_contract.to_address(), admin)
}

The deployment failed with:

Invalid node count for Merkle tree: ...
// said found 1 but expecting 63

The problem was solved by adding an empty private method:

  #[private]
  fn some_private_method() {
      // private method code
  }