build: generate root crate paths correctly (#623)

We shouldn't append `proto_path` (`super` by default) if the path starts
with `crate::`.

Fixes https://github.com/hyperium/tonic/issues/548

Cargo.toml

@@ -20,5 +20,6 @@ members = [
     "tests/extern_path/my_application",
     "tests/integration_tests",
     "tests/stream_conflict",
+    "tests/root-crate-path",
 ]
 

tests/root-crate-path/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "root-crate-path"
+version = "0.1.0"
+authors = ["Lucio Franco <luciofranco14@gmail.com>"]
+edition = "2018"
+publish = false
+license = "MIT"
+
+[dependencies]
+tonic = { path = "../../tonic" }
+prost = "0.7"
+
+[build_dependencies]
+tonic-build = { path = "../../tonic-build" }

tests/root-crate-path/build.rs

@@ -0,0 +1,7 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::configure()
+        .extern_path(".foo.bar.baz.Animal", "crate::Animal")
+        .compile(&["foo.proto"], &["."])?;
+
+    Ok(())
+}

tests/root-crate-path/foo.proto

@@ -0,0 +1,10 @@
+syntax = "proto2";
+
+package foo.bar.baz;
+
+message Animal {
+  optional string name = 1;
+}
+service Zoo {
+  rpc process_animal(Animal) returns (Animal) {};
+}

tests/root-crate-path/src/main.rs

@@ -0,0 +1,19 @@
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Animal {
+    #[prost(string, optional, tag = "1")]
+    pub name: ::core::option::Option<::prost::alloc::string::String>,
+}
+
+// pub mod foo;
+
+pub mod foo {
+    pub mod bar {
+        pub mod baz {
+            tonic::include_proto!("foo.bar.baz");
+        }
+    }
+}
+
+fn main() {
+    println!("Hello, world!");
+}

tonic-build/src/prost.rs

@@ -102,22 +102,28 @@ impl crate::Method for Method {
         proto_path: &str,
         compile_well_known_types: bool,
     ) -> (TokenStream, TokenStream) {
-        let request = if (self.input_proto_type.starts_with(".google.protobuf")
-            && !compile_well_known_types)
+        let request = if (is_google_type(&self.input_proto_type) && !compile_well_known_types)
             || self.input_type.starts_with("::")
         {
             self.input_type.parse::<TokenStream>().unwrap()
+        } else if self.input_type.starts_with("crate::") {
+            syn::parse_str::<syn::Path>(&self.input_type)
+                .unwrap()
+                .to_token_stream()
         } else {
             syn::parse_str::<syn::Path>(&format!("{}::{}", proto_path, self.input_type))
                 .unwrap()
                 .to_token_stream()
         };
 
-        let response = if (self.output_proto_type.starts_with(".google.protobuf")
-            && !compile_well_known_types)
+        let response = if (is_google_type(&self.output_proto_type) && !compile_well_known_types)
             || self.output_type.starts_with("::")
         {
             self.output_type.parse::<TokenStream>().unwrap()
+        } else if self.output_type.starts_with("crate::") {
+            syn::parse_str::<syn::Path>(&self.output_type)
+                .unwrap()
+                .to_token_stream()
         } else {
             syn::parse_str::<syn::Path>(&format!("{}::{}", proto_path, self.output_type))
                 .unwrap()
@@ -128,6 +134,10 @@ impl crate::Method for Method {
     }
 }
 
+fn is_google_type(ty: &str) -> bool {
+    ty.starts_with(".google.protobuf")
+}
+
 struct ServiceGenerator {
     builder: Builder,
     clients: TokenStream,