support introspection object types

NEXT_CHANGELOG.md

@@ -24,7 +24,6 @@ Description! And a link to a [reference](http://url)
 By [@USERNAME](https://github.com/USERNAME) in https://github.com/apollographql/router/pull/PULL_NUMBER
 -->
 
-
 # [0.9.5] (unreleased) - 2022-mm-dd
 ## ❗ BREAKING ❗
 ## 🚀 Features ( :rocket: )
@@ -40,6 +39,14 @@ export APOLLO_UPLINK_ENDPOINTS="https://aws.uplink.api.apollographql.com/, https
 By [@bnjjj](https://github.com/bnjjj) in https://github.com/apollographql/router/pull/872
 
 ## 🐛 Fixes ( :bug: )
+
+### Support introspection object types ([PR #1240](https://github.com/apollographql/router/pull/1240))
+
+Introspection queries can use a set of object types defined in the specification. The query parsing code was not recognizing them,
+resulting in some introspection queries not working.
+
+By [@Geal](https://github.com/Geal) in https://github.com/apollographql/router/pull/1240
+
 ## 🛠 Maintenance ( :hammer_and_wrench: )
 ## 📚 Documentation ( :books: )
-## 🐛 Fixes ( :bug: )
+## 🐛 Fixes ( :bug: )

apollo-router/src/spec/introspection_types.graphql

@@ -0,0 +1,94 @@
+#source: https://spec.graphql.org/October2021/#sec-Schema-Introspection.Schema-Introspection-Schema
+
+type __Schema {
+  description: String
+  types: [__Type!]!
+  queryType: __Type!
+  mutationType: __Type
+  subscriptionType: __Type
+  directives: [__Directive!]!
+}
+
+type __Type {
+  kind: __TypeKind!
+  name: String
+  description: String
+  # must be non-null for OBJECT and INTERFACE, otherwise null.
+  fields(includeDeprecated: Boolean = false): [__Field!]
+  # must be non-null for OBJECT and INTERFACE, otherwise null.
+  interfaces: [__Type!]
+  # must be non-null for INTERFACE and UNION, otherwise null.
+  possibleTypes: [__Type!]
+  # must be non-null for ENUM, otherwise null.
+  enumValues(includeDeprecated: Boolean = false): [__EnumValue!]
+  # must be non-null for INPUT_OBJECT, otherwise null.
+  inputFields: [__InputValue!]
+  # must be non-null for NON_NULL and LIST, otherwise null.
+  ofType: __Type
+  # may be non-null for custom SCALAR, otherwise null.
+  specifiedByURL: String
+}
+
+enum __TypeKind {
+  SCALAR
+  OBJECT
+  INTERFACE
+  UNION
+  ENUM
+  INPUT_OBJECT
+  LIST
+  NON_NULL
+}
+
+type __Field {
+  name: String!
+  description: String
+  args: [__InputValue!]!
+  type: __Type!
+  isDeprecated: Boolean!
+  deprecationReason: String
+}
+
+type __InputValue {
+  name: String!
+  description: String
+  type: __Type!
+  defaultValue: String
+}
+
+type __EnumValue {
+  name: String!
+  description: String
+  isDeprecated: Boolean!
+  deprecationReason: String
+}
+
+type __Directive {
+  name: String!
+  description: String
+  locations: [__DirectiveLocation!]!
+  args: [__InputValue!]!
+  isRepeatable: Boolean!
+}
+
+enum __DirectiveLocation {
+  QUERY
+  MUTATION
+  SUBSCRIPTION
+  FIELD
+  FRAGMENT_DEFINITION
+  FRAGMENT_SPREAD
+  INLINE_FRAGMENT
+  VARIABLE_DEFINITION
+  SCHEMA
+  SCALAR
+  OBJECT
+  FIELD_DEFINITION
+  ARGUMENT_DEFINITION
+  INTERFACE
+  UNION
+  ENUM
+  ENUM_VALUE
+  INPUT_OBJECT
+  INPUT_FIELD_DEFINITION
+}

apollo-router/src/spec/query.rs

@@ -4568,4 +4568,46 @@ mod tests {
             }},
         );
     }
+
+    #[test]
+    fn parse_introspection_query() {
+        let schema = "type Query {
+            foo: String
+            stuff: Bar
+            array: [Bar]
+            baz: String
+        }
+        type Bar {
+            bar: String
+            baz: String
+        }";
+
+        let schema = with_supergraph_boilerplate(schema)
+            .parse::<Schema>()
+            .expect("could not parse schema");
+        let api_schema = schema.api_schema();
+
+        let query = "{
+            __type(name: \"Bar\") {
+              name
+              fields {
+                name
+                type {
+                  name
+                }
+              }
+            }
+          }}";
+        let _ = Query::parse(query, api_schema).unwrap();
+
+        let query = "query {
+            __schema {
+              queryType {
+                name
+              }
+            }
+          }";
+
+        let _ = Query::parse(query, api_schema).unwrap();
+    }
 }

apollo-router/src/spec/schema.rs

@@ -46,7 +46,8 @@ impl std::str::FromStr for Schema {
         }
 
         fn parse(schema: &str) -> Result<Schema, SchemaError> {
-            let parser = apollo_parser::Parser::new(schema);
+            let schema_with_introspection = Schema::with_introspection(schema);
+            let parser = apollo_parser::Parser::new(&schema_with_introspection);
             let tree = parser.parse();
 
             // Trace log recursion limit data
@@ -430,6 +431,14 @@ impl Schema {
     pub fn boxed(self) -> Box<Self> {
         Box::new(self)
     }
+
+    fn with_introspection(schema: &str) -> String {
+        format!(
+            "{}\n{}",
+            schema,
+            include_str!("introspection_types.graphql")
+        )
+    }
 }
 
 #[derive(Debug)]

apollo-router/src/spec/selection.rs

@@ -87,8 +87,10 @@ impl Selection {
 
                 let field_type = if field_name.as_str() == "__typename" {
                     FieldType::String
-                } else if field_name.starts_with("__") {
-                    FieldType::Introspection(field_name.clone())
+                } else if field_name == "__schema" {
+                    FieldType::Introspection("__Schema".to_string())
+                } else if field_name == "__type" {
+                    FieldType::Introspection("__Type".to_string())
                 } else {
                     current_type
                         .inner_type_name()