tonic-build fails in replace_wellknown when .extern_path is specified

[swilcox3]

Bug Report

Version

tonic = "0.1.1"
tonic-build = "0.1.1"

Platform

64-bit Windows 10

Crates

tonic-build

Description

I've got two crates, one is a library and one is a tonic server. The library has a .proto that it builds with prost-build which I want to include in the server .proto, so I've specified them with .extern_path. When I build, I get this error (only relevant parts of backtrace included):

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error("expected identifier")', src\libcore\result.rs:1165:5
  14:     0x7ff60ba70c68 - core::result::Result<syn::path::Path, syn::error::Error>::unwrap<syn::path::Path,syn::error::Error>
                               at /rustc/73528e339aae0f17a15ffa49a8ac608f50c6cf14\src\libcore\result.rs:933
  15:     0x7ff60ba678e5 - tonic_build::replace_wellknown
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\lib.rs:332
  16:     0x7ff60ba8e63e - tonic_build::server::generate_streaming
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\server.rs:397
  17:     0x7ff60ba81b1f - tonic_build::server::generate_methods
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\server.rs:228
  18:     0x7ff60ba738df - tonic_build::server::generate
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\server.rs:8
  19:     0x7ff60ba66ac6 - tonic_build::{{impl}}::generate
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\lib.rs:254
  20:     0x7ff60bc9ae8a - prost_build::code_generator::{{impl}}::push_service::{{closure}}
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\prost-build-0.6.1\src\code_generator.rs:676
  21:     0x7ff60bc78831 - core::option::Option<mut alloc::boxed::Box<ServiceGenerator>*>::map<mut alloc::boxed::Box<ServiceGenerator>*,(),closure-1>
                               at /rustc/73528e339aae0f17a15ffa49a8ac608f50c6cf14\src\libcore\option.rs:447
  22:     0x7ff60bc9a246 - prost_build::code_generator::CodeGenerator::push_service
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\prost-build-0.6.1\src\code_generator.rs:673
  23:     0x7ff60bc913b0 - prost_build::code_generator::CodeGenerator::generate
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\prost-build-0.6.1\src\code_generator.rs:103
  24:     0x7ff60bc5bba0 - prost_build::Config::generate
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\prost-build-0.6.1\src\lib.rs:593
  25:     0x7ff60ba2c000 - prost_build::Config::compile_protos<str*>
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\prost-build-0.6.1\src\lib.rs:552
  26:     0x7ff60ba4eb61 - tonic_build::Builder::compile<str*>
                               at C:\Users\SWilcox\.cargo\registry\src\github.aaakk.us.kg-1ecc6299db9ec823\tonic-build-0.1.1\src\lib.rs:167

My build.rs looks like this:

fn main() {
    tonic_build::configure()
        .build_client(true)
        .build_server(true)
        .extern_path(".obj_traits", "::obj_traits")
        .compile(&["../model_state.proto"], &["../", "../../obj-traits/"])
        .unwrap_or_else(|e| panic!("Failed to compile protos {:?}", e));
    /*prost_build::Config::default()
    .extern_path(".obj_traits", "::obj_traits")
    .compile_protos(&["../model_state.proto"], &["../", "../../obj-traits/"])
    .unwrap_or_else(|e| panic!("Failed to compile protos {:?}", e));*/
}

You can see in the commented section that I've tested this with prost_build, and that succeeds just fine.

Here's the server model_state.proto:

syntax = "proto3";
import "obj_traits.proto";

package model_state;

message AddEntityInput
{
    string file = 1;
    string user = 2;
    obj_traits.DataObjectMsg object = 3;
}

message GetEntityInput
{
    string file = 1;
    string user = 2;
    string id = 3;
}

message ModifyEntityInput
{
    string file = 1;
    string user = 2;
    obj_traits.DataObjectMsg object = 3;
}

message DeleteEntityInput
{
    string file = 1;
    string user = 2;
    string id = 3;
}

message ClearFileInput
{
    string file = 1;
}

message ClearUserInput
{
    string file = 1;
    string user = 2;
}

message EmptyOutput{}

service ModelState {
    rpc AddEntity(stream AddEntityInput) returns (stream obj_traits.UpdateChangeMsg);
    rpc GetEntity(stream GetEntityInput) returns (stream obj_traits.DataObjectMsg);
    rpc ModifyEntity(stream ModifyEntityInput) returns (stream obj_traits.UpdateChangeMsg);
    rpc DeleteEntity(stream DeleteEntityInput) returns (stream obj_traits.UpdateChangeMsg);
    rpc ClearUser(ClearUserInput) returns (EmptyOutput);
    rpc ClearFile(ClearFileInput) returns (EmptyOutput); 
}

And the library obj_traits.proto:

syntax = "proto3";

package obj_traits;

message DataObjectMsg
{
    string obj_type = 1;
    bytes object = 2;
}

message MeshDataMsg
{
    string id = 1;
    repeated double positions = 2;
    repeated uint64 indices = 3;
    string meta_json = 4;
}

message UpdateOutputMsg
{
    oneof output {
        string empty = 1;
        string delete = 2;
        MeshDataMsg mesh = 3;
        string other_json = 4;
    }
}

message UpdateChangeMsg
{
    uint64 change = 1;
    UpdateOutputMsg update = 2;
}

I see that the failure is coming from replace_wellknown. I used to have a reference to a well known type in the server .proto, but I removed it. This error doesn't go away after a clean build either.

[swilcox3]

It seems to be related to using obj_traits.* in the output of the rpc definitions. If I change the service to look like this it works fine:

message AddEntityOutput
{
    obj_traits.UpdateChangeMsg update = 1;
}

message GetEntityOutput
{
    obj_traits.DataObjectMsg object = 1;
}

message ModifyEntityOutput
{
    obj_traits.UpdateChangeMsg update = 2;
}

message DeleteEntityOutput
{
    obj_traits.UpdateChangeMsg update = 3;
}

message EmptyOutput{}

service ModelState {
    rpc AddEntity(stream AddEntityInput) returns (stream AddEntityOutput);
    rpc GetEntity(stream GetEntityInput) returns (stream GetEntityOutput);
    rpc ModifyEntity(stream ModifyEntityInput) returns (stream ModifyEntityOutput);
    rpc DeleteEntity(stream DeleteEntityInput) returns (stream DeleteEntityOutput);
    rpc ClearUser(ClearUserInput) returns (EmptyOutput);
    rpc ClearFile(ClearFileInput) returns (EmptyOutput); 
}

That's better practice anyways, so I'll go ahead and do that going forward, but the first case should either work out of the box or have a more descriptive error message.

[cthulhua]

This looks to me like #260 which was merged to master in #261
Do you mind seeing if this works against master?

[swilcox3]

Yep, that looks like the same issue. Thanks!