From 3306f85a8ab46118da3606d72a40b6e0a4000367 Mon Sep 17 00:00:00 2001
From: Sunli <scott_s829@163.com>
Date: Thu, 28 Oct 2021 16:56:08 +0800
Subject: [PATCH] Subscription typename - [GraphQL - October 2021] #681

---
 derive/src/merged_object.rs                    |  1 +
 derive/src/merged_subscription.rs              |  1 +
 derive/src/object.rs                           |  2 ++
 derive/src/simple_object.rs                    |  2 ++
 derive/src/subscription.rs                     |  1 +
 src/registry/mod.rs                            |  3 +++
 src/types/connection/connection_type.rs        |  1 +
 src/types/connection/edge.rs                   |  1 +
 src/types/empty_mutation.rs                    |  1 +
 src/types/empty_subscription.rs                |  1 +
 src/types/maybe_undefined.rs                   |  2 +-
 src/types/merged_object.rs                     |  1 +
 src/validation/rules/fields_on_correct_type.rs |  5 +++++
 src/validation/test_harness.rs                 | 14 ++++++++++++--
 src/validation/visitor.rs                      | 11 +++++++++++
 15 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/derive/src/merged_object.rs b/derive/src/merged_object.rs
index f6ccc3fb..3ea5b313 100644
--- a/derive/src/merged_object.rs
+++ b/derive/src/merged_object.rs
@@ -90,6 +90,7 @@ pub fn generate(object_args: &args::MergedObject) -> GeneratorResult<TokenStream
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: false,
                     }
                 })
             }
diff --git a/derive/src/merged_subscription.rs b/derive/src/merged_subscription.rs
index 2b57dea8..4ce2d6ca 100644
--- a/derive/src/merged_subscription.rs
+++ b/derive/src/merged_subscription.rs
@@ -72,6 +72,7 @@ pub fn generate(object_args: &args::MergedSubscription) -> GeneratorResult<Token
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: true,
                     }
                 })
             }
diff --git a/derive/src/object.rs b/derive/src/object.rs
index 665a9976..94fa4e89 100644
--- a/derive/src/object.rs
+++ b/derive/src/object.rs
@@ -563,6 +563,7 @@ pub fn generate(
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: false,
                     });
                     #(#create_entity_types)*
                     #(#add_keys)*
@@ -630,6 +631,7 @@ pub fn generate(
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: false,
                     });
                     #(#create_entity_types)*
                     #(#add_keys)*
diff --git a/derive/src/simple_object.rs b/derive/src/simple_object.rs
index a170749d..a603e8cb 100644
--- a/derive/src/simple_object.rs
+++ b/derive/src/simple_object.rs
@@ -293,6 +293,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: false,
                     })
                 }
             }
@@ -343,6 +344,7 @@ pub fn generate(object_args: &args::SimpleObject) -> GeneratorResult<TokenStream
                         extends: #extends,
                         keys: ::std::option::Option::None,
                         visible: #visible,
+                        is_subscription: false,
                     })
                 }
 
diff --git a/derive/src/subscription.rs b/derive/src/subscription.rs
index b4a7b908..6693e9cd 100644
--- a/derive/src/subscription.rs
+++ b/derive/src/subscription.rs
@@ -456,6 +456,7 @@ pub fn generate(
                     extends: #extends,
                     keys: ::std::option::Option::None,
                     visible: ::std::option::Option::None,
+                    is_subscription: true,
                 })
             }
         }
diff --git a/src/registry/mod.rs b/src/registry/mod.rs
index 16b08433..efbd4c9f 100644
--- a/src/registry/mod.rs
+++ b/src/registry/mod.rs
@@ -199,6 +199,7 @@ pub enum MetaType {
         extends: bool,
         keys: Option<Vec<String>>,
         visible: Option<MetaVisibleFn>,
+        is_subscription: bool,
     },
     Interface {
         name: String,
@@ -375,6 +376,7 @@ impl Registry {
                     extends: false,
                     keys: None,
                     visible: None,
+                    is_subscription: false,
                 },
             );
             let ty = f(self);
@@ -508,6 +510,7 @@ impl Registry {
                 extends: false,
                 keys: None,
                 visible: None,
+                is_subscription: false,
             },
         );
 
diff --git a/src/types/connection/connection_type.rs b/src/types/connection/connection_type.rs
index 9080004a..ff0193c6 100644
--- a/src/types/connection/connection_type.rs
+++ b/src/types/connection/connection_type.rs
@@ -190,6 +190,7 @@ where
                 extends: false,
                 keys: None,
                 visible: None,
+                is_subscription: false,
             }
         })
     }
diff --git a/src/types/connection/edge.rs b/src/types/connection/edge.rs
index f6c893bb..afa69142 100644
--- a/src/types/connection/edge.rs
+++ b/src/types/connection/edge.rs
@@ -107,6 +107,7 @@ where
                 extends: false,
                 keys: None,
                 visible: None,
+                is_subscription: false,
             }
         })
     }
diff --git a/src/types/empty_mutation.rs b/src/types/empty_mutation.rs
index 481a3cb5..da90a82c 100644
--- a/src/types/empty_mutation.rs
+++ b/src/types/empty_mutation.rs
@@ -45,6 +45,7 @@ impl Type for EmptyMutation {
             extends: false,
             keys: None,
             visible: None,
+            is_subscription: false,
         })
     }
 }
diff --git a/src/types/empty_subscription.rs b/src/types/empty_subscription.rs
index 0c98e473..10d28950 100644
--- a/src/types/empty_subscription.rs
+++ b/src/types/empty_subscription.rs
@@ -25,6 +25,7 @@ impl Type for EmptySubscription {
             extends: false,
             keys: None,
             visible: None,
+            is_subscription: true,
         })
     }
 }
diff --git a/src/types/maybe_undefined.rs b/src/types/maybe_undefined.rs
index 81a6048f..b9768cb3 100644
--- a/src/types/maybe_undefined.rs
+++ b/src/types/maybe_undefined.rs
@@ -6,7 +6,7 @@ use crate::{registry, InputType, InputValueError, InputValueResult, Type, Value}
 
 /// Similar to `Option`, but it has three states, `undefined`, `null` and `x`.
 ///
-/// **Reference:** <https://spec.graphql.org/June2018/#sec-Null-Value>
+/// **Reference:** <https://spec.graphql.org/October2021/#sec-Null-Value>
 ///
 /// # Examples
 ///
diff --git a/src/types/merged_object.rs b/src/types/merged_object.rs
index c3cb026c..7b236ee4 100644
--- a/src/types/merged_object.rs
+++ b/src/types/merged_object.rs
@@ -50,6 +50,7 @@ impl<A: Type, B: Type> Type for MergedObject<A, B> {
                 extends: false,
                 keys: None,
                 visible: None,
+                is_subscription: false,
             }
         })
     }
diff --git a/src/validation/rules/fields_on_correct_type.rs b/src/validation/rules/fields_on_correct_type.rs
index 343f75f9..1b4ad9ef 100644
--- a/src/validation/rules/fields_on_correct_type.rs
+++ b/src/validation/rules/fields_on_correct_type.rs
@@ -329,4 +329,9 @@ mod tests {
         "#,
         );
     }
+
+    #[test]
+    fn typename_in_subscription_root() {
+        expect_fails_rule!(factory, "subscription { __typename }");
+    }
 }
diff --git a/src/validation/test_harness.rs b/src/validation/test_harness.rs
index 30bf611b..c691be7a 100644
--- a/src/validation/test_harness.rs
+++ b/src/validation/test_harness.rs
@@ -4,6 +4,7 @@
 
 use once_cell::sync::Lazy;
 
+use crate::futures_util::Stream;
 use crate::parser::types::ExecutableDocument;
 use crate::validation::visitor::{visit, RuleError, Visitor, VisitorContext};
 use crate::*;
@@ -345,8 +346,17 @@ impl MutationRoot {
     }
 }
 
-static TEST_HARNESS: Lazy<Schema<QueryRoot, MutationRoot, EmptySubscription>> =
-    Lazy::new(|| Schema::new(QueryRoot, MutationRoot, EmptySubscription));
+pub struct SubscriptionRoot;
+
+#[Subscription(internal)]
+impl SubscriptionRoot {
+    async fn values(&self) -> impl Stream<Item = i32> {
+        futures_util::stream::once(async move { 10 })
+    }
+}
+
+static TEST_HARNESS: Lazy<Schema<QueryRoot, MutationRoot, SubscriptionRoot>> =
+    Lazy::new(|| Schema::new(QueryRoot, MutationRoot, SubscriptionRoot));
 
 pub(crate) fn validate<'a, V, F>(
     doc: &'a ExecutableDocument,
diff --git a/src/validation/visitor.rs b/src/validation/visitor.rs
index 772d4518..0a6024c7 100644
--- a/src/validation/visitor.rs
+++ b/src/validation/visitor.rs
@@ -611,6 +611,17 @@ fn visit_selection<'a, V: Visitor<'a>>(
                         visit_field(v, ctx, field);
                     },
                 );
+            } else if ctx.current_type().map(|ty| match ty {
+                MetaType::Object {
+                    is_subscription, ..
+                } => *is_subscription,
+                _ => false,
+            }) == Some(true)
+            {
+                ctx.report_error(
+                    vec![field.pos],
+                    "Unknown field \"__typename\" on type \"Subscription\".",
+                );
             }
         }
         Selection::FragmentSpread(fragment_spread) => {