Add some type detection to make the defined schema conform to the GraphQL specification. #282

Cargo.toml

@@ -39,6 +39,7 @@ serde = { version = "1.0.104", features = ["derive"] }
 serde_json = "1.0.48"
 spin = "0.5.2"
 thiserror = "1.0.11"
+static_assertions = "1.1.0"
 
 # Feature optional dependencies
 uuid = { version = "0.8.1", optional = true, features = ["v4", "serde"] }

derive/src/enum.rs

@@ -121,6 +121,8 @@ pub fn generate(enum_args: &args::Enum, input: &DeriveInput) -> Result<TokenStre
                 Ok(#crate_name::resolver_utils::enum_value(*self).into_json().unwrap())
             }
         }
+
+        impl #crate_name::type_mark::TypeMarkEnum for #ident {}
     };
     Ok(expanded.into())
 }

derive/src/input_object.rs

@@ -166,6 +166,8 @@ pub fn generate(object_args: &args::InputObject, input: &DeriveInput) -> Result<
                 #crate_name::Value::Object(map)
             }
         }
+
+        impl #crate_name::type_mark::TypeMarkInputObject for #ident {}
     };
     Ok(expanded.into())
 }

derive/src/interface.rs

@@ -326,6 +326,8 @@ pub fn generate(interface_args: &args::Interface, input: &DeriveInput) -> Result
                 #crate_name::resolver_utils::resolve_object(ctx, self).await
             }
         }
+
+        impl #generics #crate_name::type_mark::TypeMarkInterface for #ident #generics {}
     };
     Ok(expanded.into())
 }

derive/src/object.rs

@@ -521,6 +521,8 @@ pub fn generate(object_args: &args::Object, item_impl: &mut ItemImpl) -> Result<
                 #crate_name::resolver_utils::resolve_object(ctx, self).await
             }
         }
+
+        impl #generics #crate_name::type_mark::TypeMarkObject for #self_ty #where_clause {}
     };
     Ok(expanded.into())
 }

derive/src/scalar.rs

@@ -68,6 +68,8 @@ pub fn generate(scalar_args: &args::Scalar, item_impl: &mut ItemImpl) -> Result<
                 Ok(#crate_name::ScalarType::to_value(self).into_json().unwrap())
             }
         }
+
+        impl #generic #crate_name::type_mark::TypeMarkScalar for #self_ty #where_clause {}
     };
     Ok(expanded.into())
 }

derive/src/simple_object.rs

@@ -192,6 +192,8 @@ pub fn generate(object_args: &args::Object, input: &DeriveInput) -> Result<Token
                 #crate_name::resolver_utils::resolve_object(ctx, self).await
             }
         }
+
+        impl #generics #crate_name::type_mark::TypeMarkObject for #ident #generics #where_clause {}
     };
     Ok(expanded.into())
 }

derive/src/subscription.rs

@@ -385,6 +385,8 @@ pub fn generate(object_args: &args::Object, item_impl: &mut ItemImpl) -> Result<
                 ::std::boxed::Box::pin(#crate_name::futures::stream::once(async { Err(error) }))
             }
         }
+
+        impl #crate_name::type_mark::TypeMarkSubscription for #self_ty #where_clause {}
     };
     Ok(expanded.into())
 }

derive/src/union.rs

@@ -69,6 +69,8 @@ pub fn generate(union_args: &args::Interface, input: &DeriveInput) -> Result<Tok
 
             enum_names.push(enum_name);
             type_into_impls.push(quote! {
+                #crate_name::static_assertions::assert_impl_one!(#p: #crate_name::type_mark::TypeMarkObject);
+
                 #[allow(clippy::all, clippy::pedantic)]
                 impl #generics ::std::convert::From<#p> for #ident #generics {
                     fn from(obj: #p) -> Self {
@@ -149,6 +151,8 @@ pub fn generate(union_args: &args::Interface, input: &DeriveInput) -> Result<Tok
                 #crate_name::resolver_utils::resolve_object(ctx, self).await
             }
         }
+
+        impl #generics #crate_name::type_mark::TypeMarkEnum for #ident #generics {}
     };
     Ok(expanded.into())
 }

src/lib.rs

@@ -135,6 +135,9 @@ pub mod validators;
 
 #[doc(hidden)]
 pub mod registry;
+#[doc(hidden)]
+pub mod type_mark;
+
 #[doc(hidden)]
 pub use async_stream;
 #[doc(hidden)]
@@ -148,6 +151,8 @@ pub use indexmap;
 #[doc(hidden)]
 pub use serde_json;
 #[doc(hidden)]
+pub use static_assertions;
+#[doc(hidden)]
 pub use subscription::SubscriptionType;
 
 pub use async_graphql_parser as parser;

src/type_mark.rs

@@ -0,0 +1,7 @@
+pub trait TypeMarkScalar {}
+pub trait TypeMarkObject {}
+pub trait TypeMarkInterface {}
+pub trait TypeMarkUnion {}
+pub trait TypeMarkEnum {}
+pub trait TypeMarkInputObject {}
+pub trait TypeMarkSubscription {}

src/types/connection/connection_type.rs

@@ -2,6 +2,7 @@ use crate::connection::edge::Edge;
 use crate::connection::page_info::PageInfo;
 use crate::parser::types::Field;
 use crate::resolver_utils::{resolve_object, ObjectType};
+use crate::type_mark::TypeMarkObject;
 use crate::types::connection::{CursorType, EmptyFields};
 use crate::{
     registry, Context, ContextSelectionSet, FieldResult, OutputValueType, Positioned, Result, Type,
@@ -230,3 +231,5 @@ where
         resolve_object(ctx, self).await
     }
 }
+
+impl<C, T, EC, EE> TypeMarkObject for Connection<C, T, EC, EE> {}

src/types/connection/edge.rs

@@ -1,6 +1,7 @@
 use crate::connection::EmptyFields;
 use crate::parser::types::Field;
 use crate::resolver_utils::{resolve_object, ObjectType};
+use crate::type_mark::TypeMarkObject;
 use crate::types::connection::CursorType;
 use crate::{registry, Context, ContextSelectionSet, OutputValueType, Positioned, Result, Type};
 use indexmap::map::IndexMap;
@@ -137,3 +138,5 @@ where
         resolve_object(ctx, self).await
     }
 }
+
+impl<C, T, E> TypeMarkObject for Edge<C, T, E> {}

src/types/empty_mutation.rs

@@ -1,5 +1,6 @@
 use crate::parser::types::Field;
 use crate::resolver_utils::ObjectType;
+use crate::type_mark::TypeMarkObject;
 use crate::{
     registry, Context, ContextSelectionSet, Error, OutputValueType, Positioned, QueryError, Result,
     Type,
@@ -67,3 +68,5 @@ impl OutputValueType for EmptyMutation {
         })
     }
 }
+
+impl TypeMarkObject for EmptyMutation {}

src/types/empty_subscription.rs

@@ -1,3 +1,4 @@
+use crate::type_mark::TypeMarkSubscription;
 use crate::{registry, Context, Error, Pos, QueryError, Result, SubscriptionType, Type};
 use futures::{stream, Stream};
 use std::borrow::Cow;
@@ -47,3 +48,5 @@ impl SubscriptionType for EmptySubscription {
         }))
     }
 }
+
+impl TypeMarkSubscription for EmptySubscription {}

src/types/merged_object.rs

@@ -1,6 +1,7 @@
 use crate::parser::types::Field;
 use crate::registry::{MetaType, Registry};
 use crate::resolver_utils::{resolve_object, ObjectType};
+use crate::type_mark::{TypeMarkObject, TypeMarkSubscription};
 use crate::{
     CacheControl, Context, ContextSelectionSet, Error, OutputValueType, Positioned, QueryError,
     Result, SimpleObject, Subscription, SubscriptionType, Type,
@@ -100,6 +101,8 @@ where
     }
 }
 
+impl<A, B> TypeMarkObject for MergedObject<A, B> {}
+
 impl<A, B> SubscriptionType for MergedObject<A, B>
 where
     A: SubscriptionType + Send + Sync,
@@ -121,6 +124,8 @@ where
     }
 }
 
+impl<A, B> TypeMarkSubscription for MergedObject<A, B> {}
+
 #[doc(hidden)]
 #[derive(SimpleObject, Default)]
 #[graphql(internal)]

src/types/query_root.rs

@@ -6,6 +6,7 @@ use crate::{
     Result, SimpleObject, Type,
 };
 
+use crate::type_mark::TypeMarkObject;
 use indexmap::map::IndexMap;
 use std::borrow::Cow;
 
@@ -152,3 +153,5 @@ impl<T: ObjectType + Send + Sync> OutputValueType for QueryRoot<T> {
         resolve_object(ctx, self).await
     }
 }
+
+impl<T: ObjectType + Send + Sync> TypeMarkObject for QueryRoot<T> {}