tonic-build: Codegen generates a name collision after auto-capitalization is applied, resulting in cargo build errors

[zenithlight]

Bug Report

Version

└── tonic v0.11.0
└── tonic-build v0.11.0

Platform

Linux enceladus 5.15.146.1-microsoft-standard-WSL2 #1 SMP Thu Jan 11 04:09:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Crates

tonic-build

Description

I'm trying to build protos for Cosmos using tonic-build.

One of the proto files contains both names validators and Validators:

message StakeAuthorization {
  option (cosmos_proto.implements_interface) = "cosmos.authz.v1beta1.Authorization";
  option (amino.name)                        = "cosmos-sdk/StakeAuthorization";

  // max_tokens specifies the maximum amount of tokens can be delegate to a validator. If it is
  // empty, there is no spend limit and any amount of coins can be delegated.
  cosmos.base.v1beta1.Coin max_tokens = 1 [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.Coin"];
  // validators is the oneof that represents either allow_list or deny_list
  oneof validators {
    // allow_list specifies list of validator addresses to whom grantee can delegate tokens on behalf of granter's
    // account.
    Validators allow_list = 2 [(amino.oneof_name) = "cosmos-sdk/StakeAuthorization/AllowList"];
    // deny_list specifies list of validator addresses to whom grantee can not delegate tokens.
    Validators deny_list = 3 [(amino.oneof_name) = "cosmos-sdk/StakeAuthorization/DenyList"];
  }
  // Validators defines list of validator addresses.
  message Validators {
    repeated string address = 1 [(cosmos_proto.scalar) = "cosmos.AddressString"];
  }
  // authorization_type defines one of AuthorizationType.
  AuthorizationType authorization_type = 4;
}

Because of auto-capitalization, the generated Rust includes two types both with the name Validators:

/// Nested message and enum types in `StakeAuthorization`.
pub mod stake_authorization {
    /// Validators defines list of validator addresses.
    #[allow(clippy::derive_partial_eq_without_eq)]
    #[derive(Clone, PartialEq, ::prost::Message)]
    pub struct ValidatorList {
        #[prost(string, repeated, tag = "1")]
        pub address: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
    }
    /// validators is the oneof that represents either allow_list or deny_list
    #[allow(clippy::derive_partial_eq_without_eq)]
    #[derive(Clone, PartialEq, ::prost::Oneof)]
    pub enum Validators {
        /// allow_list specifies list of validator addresses to whom grantee can delegate tokens on behalf of granter's
        /// account.
        #[prost(message, tag = "2")]
        AllowList(Validators),
        /// deny_list specifies list of validator addresses to whom grantee can not delegate tokens.
        #[prost(message, tag = "3")]
        DenyList(Validators),
    }
}

This causes cargo build to fail with errors:

error[E0428]: the name `Validators` is defined multiple times
  --> /home/lumi/code/rust-dydx-protos/target/debug/build/rust-dydx-protos-2059e937180aa0c5/out/cosmos.staking.v1beta1.rs:31:5
   |
24 |     pub struct Validators {
   |     --------------------- previous definition of the type `Validators` here
...
31 |     pub enum Validators {
   |     ^^^^^^^^^^^^^^^^^^^ `Validators` redefined here
   |
   = note: `Validators` must be defined only once in the type namespace of this module

By monkey patching the .proto to use the name ValidatorList instead of Validators I can get the build to succeed. But I'm wondering if there is any solution within tonic-build to deal with this.