fix(rs-bindgen): workaround the async Send compiler bug

fix rust-lang/rust#96865 in bindgen

Signed-off-by: Roman Volosatovs <rvolosatovs@riseup.net>

Author: rvolosatovs

Diff for: Cargo.lock

@@ -128,10 +128,10 @@ wasmtime = { version = "22", default-features = false }
 wasmtime-wasi = { version = "22", default-features = false }
 wit-bindgen = { version = "0.27", default-features = false }
 wit-bindgen-core = { version = "0.27", default-features = false }
-wit-bindgen-wrpc = { version = "0.4.2", default-features = false, path = "./crates/wit-bindgen" }
+wit-bindgen-wrpc = { version = "0.4.3", default-features = false, path = "./crates/wit-bindgen" }
 wit-bindgen-wrpc-go = { version = "0.2", default-features = false, path = "./crates/wit-bindgen-go" }
-wit-bindgen-wrpc-rust = { version = "0.4.2", default-features = false, path = "./crates/wit-bindgen-rust" }
-wit-bindgen-wrpc-rust-macro = { version = "0.4.2", default-features = false, path = "./crates/wit-bindgen-rust-macro" }
+wit-bindgen-wrpc-rust = { version = "0.4.3", default-features = false, path = "./crates/wit-bindgen-rust" }
+wit-bindgen-wrpc-rust-macro = { version = "0.4.3", default-features = false, path = "./crates/wit-bindgen-rust-macro" }
 wit-component = { version = "0.212", default-features = false }
 wit-parser = { version = "0.212", default-features = false }
 wrpc-cli = { version = "0.2", path = "./crates/cli", default-features = false }

Diff for: Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wit-bindgen-wrpc-rust-macro"
-version = "0.4.2"
+version = "0.4.3"
 description = """
 Procedural macro paired with the `wit-bindgen-wrpc` crate.
 """

Diff for: crates/wit-bindgen-rust-macro/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wit-bindgen-wrpc-rust"
-version = "0.4.2"
+version = "0.4.3"
 description = """
 Rust bindings generator for wRPC, typically used through
 the `wit-bindgen-wrpc` crate's `generate!` macro.

Diff for: crates/wit-bindgen-rust/Cargo.toml

@@ -536,10 +536,16 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
         let params = self.print_docs_and_params(func, &sig);
         match func.results.iter_types().collect::<Vec<_>>().as_slice() {
             [] => {
-                uwrite!(self.src, " -> {anyhow}::Result<()>",);
+                uwrite!(
+                    self.src,
+                    " -> impl ::core::future::Future<Output = {anyhow}::Result<()>> + Send + 'a"
+                );
             }
             [ty] => {
-                uwrite!(self.src, " -> {anyhow}::Result<",);
+                uwrite!(
+                    self.src,
+                    " -> impl ::core::future::Future<Output = {anyhow}::Result<"
+                );
                 if async_params || !paths.is_empty() {
                     self.push_str("(");
                 }
@@ -551,10 +557,13 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
                         wrpc_transport = self.gen.wrpc_transport_path(),
                     );
                 }
-                uwrite!(self.src, ">");
+                uwrite!(self.src, ">> + Send + 'a");
             }
             types => {
-                uwrite!(self.src, " -> {anyhow}::Result<(",);
+                uwrite!(
+                    self.src,
+                    " -> impl ::core::future::Future<Output = {anyhow}::Result<(",
+                );
                 for ty in types {
                     self.print_ty(ty, true, false);
                     self.push_str(", ");
@@ -566,17 +575,23 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
                         wrpc_transport = self.gen.wrpc_transport_path(),
                     );
                 }
-                uwrite!(self.src, ")>");
+                uwrite!(self.src, ")>> + Send + 'a");
             }
         };
-        self.src.push_str("{\n");
+        self.push_str(
+            r"
+        {
+        async move {",
+        );
 
         if func.results.len() == 0 || (!async_params && paths.is_empty()) {
             uwrite!(
                 self.src,
-                r#"let wrpc__ = {anyhow}::Context::context(
-            wrpc__.invoke_values_blocking(cx__,  "{instance}", "{}", ({params}), "#,
+                r#"
+                let wrpc__ = {anyhow}::Context::context(
+                    {wrpc_transport}::SendFuture::send(wrpc__.invoke_values_blocking(cx__,  "{instance}", "{}", ({params}), "#,
                 rpc_func_name(func),
+                wrpc_transport = self.gen.wrpc_transport_path(),
                 params = {
                     let s = params.join(", ");
                     if params.len() == 1 {
@@ -595,11 +610,11 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
                     self.src.push_str(".as_slice(), ");
                 }
             }
-            self.src.push_str("]).await,\n");
+            self.src.push_str("])).await,\n");
             uwriteln!(
                 self.src,
                 r#"
-            "failed to invoke `{instance}.{}`")?;"#,
+                    "failed to invoke `{instance}.{}`")?;"#,
                 func.name,
             );
             if func.results.len() == 1 {
@@ -609,9 +624,11 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
         } else {
             uwrite!(
                 self.src,
-                r#"let (wrpc__, io__) = {anyhow}::Context::context(
-            wrpc__.invoke_values(cx__,  "{instance}", "{}", ({params}), "#,
+                r#"
+                let (wrpc__, io__) = {anyhow}::Context::context(
+                    {wrpc_transport}::SendFuture::send(wrpc__.invoke_values(cx__,  "{instance}", "{}", ({params}), "#,
                 rpc_func_name(func),
+                wrpc_transport = self.gen.wrpc_transport_path(),
                 params = {
                     let s = params.join(", ");
                     if params.len() == 1 {
@@ -630,11 +647,11 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
                     self.src.push_str(".as_slice(), ");
                 }
             }
-            self.src.push_str("]).await,\n");
+            self.src.push_str("])).await,\n");
             uwriteln!(
                 self.src,
                 r#"
-            "failed to invoke `{instance}.{}`")?;"#,
+                    "failed to invoke `{instance}.{}`")?;"#,
                 func.name,
             );
             if func.results.len() == 1 {
@@ -653,7 +670,12 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
                 self.push_str("io__))\n");
             }
         }
-        self.push_str("}\n");
+        uwriteln!(
+            self.src,
+            r"
+            }}
+        }}"
+        );
 
         match func.kind {
             FunctionKind::Freestanding => {}
@@ -723,9 +745,6 @@ pub async fn serve_interface<T: {wrpc_transport}::Serve, U>(
         if !sig.private {
             self.push_str("pub ");
         }
-        if self.in_import {
-            self.push_str("async ");
-        }
         self.push_str("fn ");
         if sig.use_item_name {
             if let FunctionKind::Constructor(_) = &func.kind {

Diff for: crates/wit-bindgen-rust/src/interface.rs

@@ -1,6 +1,6 @@
 [package]
 name = "wit-bindgen-wrpc"
-version = "0.4.2"
+version = "0.4.3"
 description = """
 Rust bindings generator for wRPC.
 """