Merge pull request #438 from taiki-e/generic-subscription

Support generics in Subscription types

derive/src/subscription.rs

@@ -20,6 +20,8 @@ pub fn generate(
 ) -> GeneratorResult<TokenStream> {
     let crate_name = get_crate_name(subscription_args.internal);
     let (self_ty, self_name) = get_type_path_and_name(item_impl.self_ty.as_ref())?;
+    let generics = &item_impl.generics;
+    let where_clause = &item_impl.generics.where_clause;
     let extends = subscription_args.extends;
 
     let gql_typename = subscription_args
@@ -426,7 +428,7 @@ pub fn generate(
         #item_impl
 
         #[allow(clippy::all, clippy::pedantic)]
-        impl #crate_name::Type for #self_ty {
+        impl #generics #crate_name::Type for #self_ty #where_clause {
             fn type_name() -> ::std::borrow::Cow<'static, ::std::primitive::str> {
                 ::std::borrow::Cow::Borrowed(#gql_typename)
             }
@@ -451,7 +453,7 @@ pub fn generate(
 
         #[allow(clippy::all, clippy::pedantic)]
         #[allow(unused_braces, unused_variables)]
-        impl #crate_name::SubscriptionType for #self_ty {
+        impl #generics #crate_name::SubscriptionType for #self_ty #where_clause {
             fn create_field_stream<'__life>(
                 &'__life self,
                 ctx: &'__life #crate_name::Context<'_>,

tests/generic_types.rs

@@ -1,4 +1,5 @@
 use async_graphql::*;
+use futures_util::stream::{Stream, StreamExt};
 
 #[async_std::test]
 pub async fn test_generic_object() {
@@ -122,7 +123,7 @@ pub async fn test_input_object_generic() {
             "__type": {
                 "fields": [
                     {
-                        "name": "q1", 
+                        "name": "q1",
                         "args": [{
                             "name": "input",
                             "type": {
@@ -132,7 +133,7 @@ pub async fn test_input_object_generic() {
                         }]
                     },
                     {
-                        "name": "q2", 
+                        "name": "q2",
                         "args": [{
                             "name": "input",
                             "type": {
@@ -249,3 +250,45 @@ pub async fn test_generic_simple_object() {
         })
     );
 }
+
+#[async_std::test]
+pub async fn test_generic_subscription() {
+    struct MySubscription<T> {
+        values: Vec<T>,
+    }
+
+    #[Subscription]
+    impl<T: OutputType + Type> MySubscription<T>
+    where
+        T: Clone + Send + Sync + Unpin,
+    {
+        async fn values(&self) -> Result<impl Stream<Item = T> + '_> {
+            Ok(async_stream::stream! {
+                for value in self.values.iter().cloned() {
+                    yield value
+                }
+            })
+        }
+    }
+
+    struct Query;
+
+    #[Object]
+    impl Query {
+        async fn dummy(&self) -> bool {
+            false
+        }
+    }
+
+    let schema = Schema::new(Query, EmptyMutation, MySubscription { values: vec![1, 2] });
+    {
+        let mut stream = schema
+            .execute_stream("subscription { values }")
+            .map(|resp| resp.into_result().unwrap().data)
+            .boxed();
+        for i in 1..=2 {
+            assert_eq!(value!({ "values": i }), stream.next().await.unwrap());
+        }
+        assert!(stream.next().await.is_none());
+    }
+}