additions so type can also be shareable as well as field

derive/src/args.rs

@@ -200,6 +200,8 @@ pub struct SimpleObject {
     #[darling(default)]
     pub extends: bool,
     #[darling(default)]
+    pub shareable: bool,
+    #[darling(default)]
     pub visible: Option<Visible>,
     #[darling(default, multiple, rename = "concrete")]
     pub concretes: Vec<ConcreteType>,
@@ -237,6 +239,7 @@ pub struct Object {
     pub rename_args: Option<RenameRule>,
     pub cache_control: CacheControl,
     pub extends: bool,
+    pub shareable: bool,
     pub use_type_description: bool,
     pub visible: Option<Visible>,
     pub serial: bool,
@@ -599,6 +602,8 @@ pub struct MergedObject {
     #[darling(default)]
     pub extends: bool,
     #[darling(default)]
+    pub shareable: bool,
+    #[darling(default)]
     pub visible: Option<Visible>,
     #[darling(default)]
     pub serial: bool,

derive/src/merged_object.rs

@@ -14,6 +14,7 @@ pub fn generate(object_args: &args::MergedObject) -> GeneratorResult<TokenStream
     let ident = &object_args.ident;
     let (impl_generics, ty_generics, where_clause) = object_args.generics.split_for_impl();
     let extends = object_args.extends;
+    let shareable = object_args.shareable;
     let gql_typename = object_args
         .name
         .clone()
@@ -103,6 +104,7 @@ pub fn generate(object_args: &args::MergedObject) -> GeneratorResult<TokenStream
                         fields,
                         cache_control,
                         extends: #extends,
+                        shareable: #shareable,
                         keys: ::std::option::Option::None,
                         visible: #visible,
                         is_subscription: false,

derive/src/merged_subscription.rs

@@ -74,6 +74,7 @@ pub fn generate(object_args: &args::MergedSubscription) -> GeneratorResult<Token
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        shareable: false,
                         is_subscription: true,
                         rust_typename: ::std::any::type_name::<Self>(),
                     }

derive/src/object.rs

@@ -26,6 +26,7 @@ pub fn generate(
     let (self_ty, self_name) = get_type_path_and_name(item_impl.self_ty.as_ref())?;
     let (impl_generics, _, where_clause) = item_impl.generics.split_for_impl();
     let extends = object_args.extends;
+    let shareable = object_args.shareable;
     let gql_typename = if !object_args.name_type {
         object_args
             .name
@@ -642,6 +643,7 @@ pub fn generate(
                         },
                         cache_control: #cache_control,
                         extends: #extends,
+                        shareable: #shareable,
                         keys: ::std::option::Option::None,
                         visible: #visible,
                         is_subscription: false,
@@ -681,6 +683,7 @@ pub fn generate(
                         },
                         cache_control: #cache_control,
                         extends: #extends,
+                        shareable: #shareable,
                         keys: ::std::option::Option::None,
                         visible: #visible,
                         is_subscription: false,

derive/src/simple_object.rs

@@ -30,6 +30,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
     let ident = &object_args.ident;
     let (impl_generics, ty_generics, where_clause) = object_args.generics.split_for_impl();
     let extends = object_args.extends;
+    let shareable = object_args.shareable;
     let gql_typename = if !object_args.name_type {
         object_args
             .name
@@ -331,6 +332,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
                         },
                         cache_control: #cache_control,
                         extends: #extends,
+                        shareable: #shareable,
                         keys: ::std::option::Option::None,
                         visible: #visible,
                         is_subscription: false,
@@ -395,6 +397,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
                         },
                         cache_control: #cache_control,
                         extends: #extends,
+                        shareable: #shareable,
                         keys: ::std::option::Option::None,
                         visible: #visible,
                         is_subscription: false,

derive/src/subscription.rs

@@ -409,6 +409,7 @@ pub fn generate(
                     extends: #extends,
                     keys: ::std::option::Option::None,
                     visible: #visible,
+                    shareable: false,
                     is_subscription: true,
                     rust_typename: ::std::any::type_name::<Self>(),
                 })

docs/en/src/apollo_federation.md

@@ -12,6 +12,8 @@
 
 - The `requires` directive is used to annotate the required input fieldset from a base type for a resolver. It is used to develop a query plan where the required fields may not be needed by the client, but the service may need additional information from other services.
 
+- The `shareable` directive is used to indicate that an object type's field is allowed to be resolved by multiple subgraphs (by default, each field can be resolved by only one subgraph).
+
 ## Entity lookup function
 
 ```rust

src/registry/export_sdl.rs

@@ -201,6 +201,7 @@ impl Registry {
                 extends,
                 keys,
                 description,
+                shareable,
                 ..
             } => {
                 if Some(name.as_str()) == self.subscription_type.as_deref()
@@ -244,6 +245,9 @@ impl Registry {
                             write!(sdl, "@key(fields: \"{}\") ", key).ok();
                         }
                     }
+                    if *shareable {
+                        write!(sdl, "@shareable ").ok();
+                    }
                 }
 
                 writeln!(sdl, "{{").ok();

src/registry/mod.rs

@@ -218,6 +218,7 @@ pub enum MetaType {
         fields: IndexMap<String, MetaField>,
         cache_control: CacheControl,
         extends: bool,
+        shareable: bool,
         keys: Option<Vec<String>>,
         visible: Option<MetaVisibleFn>,
         is_subscription: bool,
@@ -493,6 +494,7 @@ impl Registry {
                         fields: Default::default(),
                         cache_control: Default::default(),
                         extends: false,
+                        shareable: false,
                         keys: None,
                         visible: None,
                         is_subscription: false,
@@ -706,6 +708,7 @@ impl Registry {
                 },
                 cache_control: Default::default(),
                 extends: false,
+                shareable: false,
                 keys: None,
                 visible: None,
                 is_subscription: false,

src/types/empty_mutation.rs

@@ -54,6 +54,7 @@ impl OutputType for EmptyMutation {
             fields: Default::default(),
             cache_control: Default::default(),
             extends: false,
+            shareable: false,
             keys: None,
             visible: None,
             is_subscription: false,

src/types/empty_subscription.rs

@@ -23,6 +23,7 @@ impl SubscriptionType for EmptySubscription {
             fields: Default::default(),
             cache_control: Default::default(),
             extends: false,
+            shareable: false,
             keys: None,
             visible: None,
             is_subscription: true,

src/types/merged_object.rs

@@ -77,6 +77,7 @@ where
                 fields,
                 cache_control: cc,
                 extends: false,
+                shareable: false,
                 keys: None,
                 visible: None,
                 is_subscription: false,
@@ -135,6 +136,7 @@ where
                 fields,
                 cache_control: cc,
                 extends: false,
+                shareable: false,
                 keys: None,
                 visible: None,
                 is_subscription: false,
@@ -168,6 +170,7 @@ impl SubscriptionType for MergedObjectTail {
             fields: Default::default(),
             cache_control: Default::default(),
             extends: false,
+            shareable: false,
             keys: None,
             visible: None,
             is_subscription: false,

tests/federation.rs

@@ -290,26 +290,41 @@ pub async fn test_entity_union() {
 #[tokio::test]
 pub async fn test_entity_shareable() {
     #[derive(SimpleObject)]
-    struct MyObj {
+    struct MyObjFieldShareable {
         #[graphql(shareable)]
+        field_shareable_a: i32,
+    }
+
+    #[derive(SimpleObject)]
+    #[graphql(shareable)]
+    struct MyObjShareable {
         a: i32,
     }
 
+
     struct Query;
 
     #[Object(extends)]
     impl Query {
         #[graphql(entity)]
-        async fn find_obj(&self, _id: i32) -> MyObj {
+        async fn find_obj_field_shareable(&self, _id: i32) -> MyObjFieldShareable {
+            todo!()
+        }
+        #[graphql(entity)]
+        async fn find_obj_shareable(&self, _id: i32) -> MyObjShareable {
             todo!()
         }
     }
 
     let schema_sdl = Schema::new(Query, EmptyMutation, EmptySubscription)
         .sdl_with_options(SDLExportOptions::new().federation());
-    println!("{}", schema_sdl);
     assert_eq!(
-        schema_sdl.contains("a: Int! @shareable"),
+        schema_sdl.contains("fieldShareableA: Int! @shareable"),
+        true
+    );
+
+    assert_eq!(
+        schema_sdl.contains(r#"MyObjShareable @key(fields: "id") @shareable"#),
         true
     );
 }