subscription

Author: kamilkisiela

src/ast/operation_visitor.rs

@@ -184,7 +184,26 @@ fn visit_definitions<'a, Visitor, UserContext>(
                     })
                 }
                 OperationDefinition::Subscription(_) => {
-                    context.schema.subscription_type().map(|t| &t.name)
+                    context
+                        .schema
+                        .subscription_type()
+                        .map(|t| &t.name)
+                        .or_else(|| {
+                            // Awkward hack but enables me to move forward
+                            // Somehow the `subscription_type()` gives None, even though `Subscription` type is defined in the schema.
+                            if let Some(type_definition) =
+                                context.schema.type_by_name("Subscription")
+                            {
+                                return match type_definition {
+                                    graphql_parser::schema::TypeDefinition::Object(object_type) => {
+                                        Some(&object_type.name)
+                                    }
+                                    _ => None,
+                                };
+                            }
+
+                            None
+                        })
                 }
             },
         };

src/validation/rules/fields_on_correct_type.rs

@@ -115,6 +115,9 @@ pub static FIELDS_ON_CORRECT_TYPE_TEST_SCHEMA: &str = "
   type Mutation {
     deletePetByName(name: String): Pet
   }
+  type Subscription {
+    onNewPet: Pet
+  }
 ";
 
 #[test]
@@ -258,6 +261,27 @@ fn unknown_mutation_field() {
     );
 }
 
+#[test]
+fn unknown_subscription_field() {
+    use crate::validation::test_utils::*;
+
+    let mut plan = create_plan_from_rule(Box::new(FieldsOnCorrectType {}));
+    let errors = test_operation_with_schema(
+        "subscription test {
+          unknownField
+        }",
+        &FIELDS_ON_CORRECT_TYPE_TEST_SCHEMA,
+        &mut plan,
+    );
+
+    let messages = get_messages(&errors);
+    assert_eq!(messages.len(), 1);
+    assert_eq!(
+        messages,
+        vec!["Cannot query field \"unknownField\" on type \"Subscription\"."]
+    );
+}
+
 #[test]
 fn reports_errors_when_type_is_known_again() {
     use crate::validation::test_utils::*;