fix(tonic): Remove Sync requirement for streams (#804)

Cargo.toml

@@ -1,29 +1,24 @@
 [workspace]
 members = [
-    "tonic",
-    "tonic-build",
-    "tonic-health",
-    "tonic-types",
-    "tonic-reflection",
-    "tonic-web",
-
-    # Non-published crates
-    "examples",
-    "interop",
-
-    # Tests
-    "tests/included_service",
-    "tests/same_name",
-    "tests/service_named_service",
-    "tests/wellknown",
-    "tests/wellknown-compiled",
-    "tests/extern_path/uuid",
-    "tests/ambiguous_methods",
-    "tests/extern_path/my_application",
-    "tests/integration_tests",
-    "tests/stream_conflict",
-    "tests/root-crate-path",
-    "tests/compression",
-    "tonic-web/tests/integration"
+  "tonic",
+  "tonic-build",
+  "tonic-health",
+  "tonic-types",
+  "tonic-reflection",
+  "tonic-web", # Non-published crates
+  "examples",
+  "interop", # Tests
+  "tests/included_service",
+  "tests/same_name",
+  "tests/service_named_service",
+  "tests/wellknown",
+  "tests/wellknown-compiled",
+  "tests/extern_path/uuid",
+  "tests/ambiguous_methods",
+  "tests/extern_path/my_application",
+  "tests/integration_tests",
+  "tests/stream_conflict",
+  "tests/root-crate-path",
+  "tests/compression",
+  "tonic-web/tests/integration",
 ]
-

examples/routeguide-tutorial.md

@@ -300,7 +300,7 @@ impl RouteGuide for RouteGuideService {
         unimplemented!()
     }
 
-    type RouteChatStream = Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>>;
+    type RouteChatStream = Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send  + 'static>>;
 
     async fn route_chat(
         &self,
@@ -493,7 +493,7 @@ use std::collections::HashMap;
 
 ```rust
 type RouteChatStream =
-    Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>>;
+    Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send  + 'static>>;
 
 
 async fn route_chat(

examples/src/authentication/server.rs

@@ -8,7 +8,7 @@ use std::pin::Pin;
 use tonic::{metadata::MetadataValue, transport::Server, Request, Response, Status, Streaming};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Default)]
 pub struct EchoServer;

examples/src/dynamic_load_balance/server.rs

@@ -11,7 +11,7 @@ use tonic::{transport::Server, Request, Response, Status, Streaming};
 use pb::{EchoRequest, EchoResponse};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Debug)]
 pub struct EchoServer {

examples/src/hyper_warp_multiplex/server.rs

@@ -35,7 +35,7 @@ use echo::{
     EchoRequest, EchoResponse,
 };
 
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Default)]
 pub struct MyGreeter {}

examples/src/load_balance/server.rs

@@ -11,7 +11,7 @@ use tonic::{transport::Server, Request, Response, Status, Streaming};
 use pb::{EchoRequest, EchoResponse};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Debug)]
 pub struct EchoServer {

examples/src/multiplex/server.rs

@@ -20,7 +20,7 @@ use echo::{
     EchoRequest, EchoResponse,
 };
 
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {

examples/src/routeguide/server.rs

@@ -102,8 +102,7 @@ impl RouteGuide for RouteGuideService {
         Ok(Response::new(summary))
     }
 
-    type RouteChatStream =
-        Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + Sync + 'static>>;
+    type RouteChatStream = Pin<Box<dyn Stream<Item = Result<RouteNote, Status>> + Send + 'static>>;
 
     async fn route_chat(
         &self,

examples/src/streaming/server.rs

@@ -12,7 +12,7 @@ use tonic::{transport::Server, Request, Response, Status, Streaming};
 use pb::{EchoRequest, EchoResponse};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Debug)]
 pub struct EchoServer {}

examples/src/tls/server.rs

@@ -14,7 +14,7 @@ use tonic::{
 };
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Default)]
 pub struct EchoServer;

examples/src/tls_client_auth/server.rs

@@ -9,7 +9,7 @@ use tonic::transport::{Certificate, Identity, Server, ServerTlsConfig};
 use tonic::{Request, Response, Status};
 
 type EchoResult<T> = Result<Response<T>, Status>;
-type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send + Sync>>;
+type ResponseStream = Pin<Box<dyn Stream<Item = Result<EchoResponse, Status>> + Send>>;
 
 #[derive(Default)]
 pub struct EchoServer;

interop/src/server.rs

@@ -18,9 +18,8 @@ pub struct TestService;
 
 type Result<T> = std::result::Result<Response<T>, Status>;
 type Streaming<T> = Request<tonic::Streaming<T>>;
-type Stream<T> = Pin<
-    Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + Sync + 'static>,
->;
+type Stream<T> =
+    Pin<Box<dyn futures_core::Stream<Item = std::result::Result<T, Status>> + Send + 'static>>;
 type BoxFuture<T, E> = Pin<Box<dyn Future<Output = std::result::Result<T, E>> + Send + 'static>>;
 
 #[tonic::async_trait]

tests/compression/src/lib.rs

@@ -69,7 +69,7 @@ impl test_server::Test for Svc {
     }
 
     type CompressOutputServerStreamStream =
-        Pin<Box<dyn Stream<Item = Result<SomeData, Status>> + Send + Sync + 'static>>;
+        Pin<Box<dyn Stream<Item = Result<SomeData, Status>> + Send + 'static>>;
 
     async fn compress_output_server_stream(
         &self,
@@ -110,7 +110,7 @@ impl test_server::Test for Svc {
     }
 
     type CompressInputOutputBidirectionalStreamStream =
-        Pin<Box<dyn Stream<Item = Result<SomeData, Status>> + Send + Sync + 'static>>;
+        Pin<Box<dyn Stream<Item = Result<SomeData, Status>> + Send + 'static>>;
 
     async fn compress_input_output_bidirectional_stream(
         &self,

tests/integration_tests/Cargo.toml

@@ -12,14 +12,15 @@ version = "0.1.0"
 bytes = "1.0"
 futures-util = "0.3"
 prost = "0.9"
+tokio = {version = "1.0", features = ["macros", "rt-multi-thread", "net"]}
 tonic = {path = "../../tonic"}
 
 [dev-dependencies]
+async-stream = "0.3"
 futures = "0.3"
 http = "0.2"
 http-body = "0.4"
 hyper = "0.14"
-tokio = {version = "1.0", features = ["macros", "rt-multi-thread", "net"]}
 tokio-stream = {version = "0.1.5", features = ["net"]}
 tower = {version = "0.4", features = []}
 tower-service = "0.3"

tests/integration_tests/src/lib.rs

@@ -2,3 +2,54 @@ pub mod pb {
     tonic::include_proto!("test");
     tonic::include_proto!("stream");
 }
+
+pub mod mock {
+    use std::{
+        pin::Pin,
+        task::{Context, Poll},
+    };
+
+    use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
+    use tonic::transport::server::Connected;
+
+    #[derive(Debug)]
+    pub struct MockStream(pub tokio::io::DuplexStream);
+
+    impl Connected for MockStream {
+        type ConnectInfo = ();
+
+        /// Create type holding information about the connection.
+        fn connect_info(&self) -> Self::ConnectInfo {}
+    }
+
+    impl AsyncRead for MockStream {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            cx: &mut Context<'_>,
+            buf: &mut ReadBuf<'_>,
+        ) -> Poll<std::io::Result<()>> {
+            Pin::new(&mut self.0).poll_read(cx, buf)
+        }
+    }
+
+    impl AsyncWrite for MockStream {
+        fn poll_write(
+            mut self: Pin<&mut Self>,
+            cx: &mut Context<'_>,
+            buf: &[u8],
+        ) -> Poll<std::io::Result<usize>> {
+            Pin::new(&mut self.0).poll_write(cx, buf)
+        }
+
+        fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
+            Pin::new(&mut self.0).poll_flush(cx)
+        }
+
+        fn poll_shutdown(
+            mut self: Pin<&mut Self>,
+            cx: &mut Context<'_>,
+        ) -> Poll<std::io::Result<()>> {
+            Pin::new(&mut self.0).poll_shutdown(cx)
+        }
+    }
+}

tests/integration_tests/tests/status.rs

@@ -1,6 +1,7 @@
 use bytes::Bytes;
 use futures_util::FutureExt;
 use http::Uri;
+use integration_tests::mock::MockStream;
 use integration_tests::pb::{
     test_client, test_server, test_stream_client, test_stream_server, Input, InputStream, Output,
     OutputStream,
@@ -125,9 +126,8 @@ async fn status_with_metadata() {
     jh.await.unwrap();
 }
 
-type Stream<T> = std::pin::Pin<
-    Box<dyn futures::Stream<Item = std::result::Result<T, Status>> + Send + Sync + 'static>,
->;
+type Stream<T> =
+    std::pin::Pin<Box<dyn futures::Stream<Item = std::result::Result<T, Status>> + Send + 'static>>;
 
 #[tokio::test]
 async fn status_from_server_stream() {
@@ -184,7 +184,7 @@ async fn status_from_server_stream_with_source() {
     let channel = Endpoint::try_from("http://[::]:50051")
         .unwrap()
         .connect_with_connector_lazy(tower::service_fn(move |_: Uri| async move {
-            Err::<mock::MockStream, _>(std::io::Error::new(std::io::ErrorKind::Other, "WTF"))
+            Err::<MockStream, _>(std::io::Error::new(std::io::ErrorKind::Other, "WTF"))
         }))
         .unwrap();
 
@@ -201,54 +201,3 @@ fn trace_init() {
         .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
         .try_init();
 }
-
-mod mock {
-    use std::{
-        pin::Pin,
-        task::{Context, Poll},
-    };
-
-    use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
-    use tonic::transport::server::Connected;
-
-    #[derive(Debug)]
-    pub struct MockStream(pub tokio::io::DuplexStream);
-
-    impl Connected for MockStream {
-        type ConnectInfo = ();
-
-        /// Create type holding information about the connection.
-        fn connect_info(&self) -> Self::ConnectInfo {}
-    }
-
-    impl AsyncRead for MockStream {
-        fn poll_read(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-            buf: &mut ReadBuf<'_>,
-        ) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_read(cx, buf)
-        }
-    }
-
-    impl AsyncWrite for MockStream {
-        fn poll_write(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-            buf: &[u8],
-        ) -> Poll<std::io::Result<usize>> {
-            Pin::new(&mut self.0).poll_write(cx, buf)
-        }
-
-        fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_flush(cx)
-        }
-
-        fn poll_shutdown(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-        ) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_shutdown(cx)
-        }
-    }
-}

tests/integration_tests/tests/streams.rs

@@ -0,0 +1,47 @@
+use futures::FutureExt;
+use integration_tests::pb::{test_stream_server, InputStream, OutputStream};
+use tonic::{transport::Server, Request, Response, Status};
+
+type Stream<T> =
+    std::pin::Pin<Box<dyn futures::Stream<Item = std::result::Result<T, Status>> + Send + 'static>>;
+
+#[tokio::test]
+async fn status_from_server_stream_with_source() {
+    struct Svc;
+
+    #[tonic::async_trait]
+    impl test_stream_server::TestStream for Svc {
+        type StreamCallStream = Stream<OutputStream>;
+
+        async fn stream_call(
+            &self,
+            _: Request<InputStream>,
+        ) -> Result<Response<Self::StreamCallStream>, Status> {
+            let s = Unsync(0 as *mut ());
+
+            Ok(Response::new(Box::pin(s) as Self::StreamCallStream))
+        }
+    }
+
+    let svc = test_stream_server::TestStreamServer::new(Svc);
+
+    Server::builder()
+        .add_service(svc)
+        .serve("127.0.0.1:1339".parse().unwrap())
+        .now_or_never();
+}
+
+struct Unsync(*mut ());
+
+unsafe impl Send for Unsync {}
+
+impl futures::Stream for Unsync {
+    type Item = Result<OutputStream, Status>;
+
+    fn poll_next(
+        self: std::pin::Pin<&mut Self>,
+        _cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Option<Self::Item>> {
+        unimplemented!()
+    }
+}