Add keyFields to generated Interfaces

Tests/ApolloCodegenInternalTestHelpers/MockGraphQLType.swift

@@ -37,14 +37,16 @@ public extension GraphQLInterfaceType {
   class func mock(
     _ name: String = "",
     fields: [String: GraphQLField] = [:],
+    keyFields: [String] = [],
     interfaces: [GraphQLInterfaceType] = [],
     documentation: String? = nil
   ) -> GraphQLInterfaceType {
     GraphQLInterfaceType(
       name: GraphQLName(schemaName: name),
       documentation: documentation,
       fields: fields,
-      interfaces: interfaces
+      interfaces: interfaces,
+      keyFields: keyFields
     )
   }
 }

Tests/ApolloCodegenTests/AnimalKingdomAPI/AnimalKingdomIRCreationTests.swift

@@ -168,7 +168,7 @@ final class AnimalKingdomIRCreationTests: XCTestCase {
 
   func test__mergedSelections_AllAnimalsQuery_AllAnimal__isCorrect() async throws {
     // given
-    let Interface_Animal = GraphQLInterfaceType.mock("Animal")
+    let Interface_Animal = GraphQLInterfaceType.mock("Animal", keyFields: ["id"])
 
     try await buildOperation()
 

Tests/ApolloCodegenTests/CodeGeneration/Templates/InterfaceTemplateTests.swift

@@ -19,11 +19,13 @@ class InterfaceTemplateTests: XCTestCase {
     name: String = "Dog",
     customName: String? = nil,
     documentation: String? = nil,
+    keyFields: [String] = [],
     config: ApolloCodegenConfiguration = .mock()
   ) {
     let interfaceType = GraphQLInterfaceType.mock(
       name,
       fields: [:],
+      keyFields: keyFields,
       interfaces: [],
       documentation: documentation
     )
@@ -46,7 +48,7 @@ class InterfaceTemplateTests: XCTestCase {
     buildSubject(name: "aDog")
 
     let expected = """
-    static let ADog = ApolloAPI.Interface(name: "aDog")
+    static let ADog = ApolloAPI.Interface(name: "aDog", keyFields: nil)
     """
 
     // when
@@ -68,7 +70,7 @@ class InterfaceTemplateTests: XCTestCase {
 
     let expected = """
     /// \(documentation)
-    static let Dog = ApolloAPI.Interface(name: "Dog")
+    static let Dog = ApolloAPI.Interface(name: "Dog", keyFields: nil)
     """
 
     // when
@@ -88,7 +90,7 @@ class InterfaceTemplateTests: XCTestCase {
     )
 
     let expected = """
-    static let Dog = ApolloAPI.Interface(name: "Dog")
+    static let Dog = ApolloAPI.Interface(name: "Dog", keyFields: nil)
     """
 
     // when
@@ -108,7 +110,7 @@ class InterfaceTemplateTests: XCTestCase {
     )
 
     let expected = """
-    static let Dog = Apollo.Interface(name: "Dog")
+    static let Dog = Apollo.Interface(name: "Dog", keyFields: nil)
     """
 
     // when
@@ -128,7 +130,7 @@ class InterfaceTemplateTests: XCTestCase {
       buildSubject(name: keyword)
 
       let expected = """
-      static let \(keyword.firstUppercased)_Interface = ApolloAPI.Interface(name: "\(keyword)")
+      static let \(keyword.firstUppercased)_Interface = ApolloAPI.Interface(name: "\(keyword)", keyFields: nil)
       """
 
       // when
@@ -150,7 +152,28 @@ class InterfaceTemplateTests: XCTestCase {
 
     let expected = """
     // Renamed from GraphQL schema value: 'MyInterface'
-    static let MyCustomInterface = ApolloAPI.Interface(name: "MyInterface")
+    static let MyCustomInterface = ApolloAPI.Interface(name: "MyInterface", keyFields: nil)
+    """
+
+    // when
+    let actual = renderSubject()
+
+    // then
+    expect(actual).to(equalLineByLine(expected))
+  }
+
+  func test__render__givenInterface_withKeyFields_shouldRenderKeyFields() throws {
+    // given
+    buildSubject(
+      name: "IndexedNode",
+      keyFields: ["parentID", "index"]
+    )
+
+    let expected = """
+    static let IndexedNode = ApolloAPI.Interface(name: "IndexedNode", keyFields: [
+      "parentID",
+      "index"
+    ])
     """
 
     // when

Tests/ApolloTests/CacheKeyResolutionTests.swift

@@ -260,4 +260,18 @@ class CacheKeyResolutionTests: XCTestCase {
     expect(actual).to(beNil())
   }
 
+  func test__schemaConfiguration__givenInterfaceWithKeyField_shouldReturnKeyFieldValue() {
+    let Interface = Interface(name: "Animal", keyFields: ["id"])
+
+    let object: JSONObject = [
+      "__typename": "Cat",
+      "id": "10",
+    ]
+
+    let objectDict = NetworkResponseExecutionSource().opaqueObjectDataWrapper(for: object)
+    let actual = MockSchemaMetadata.cacheKey(for: objectDict, withInterface: Interface)
+
+    expect(actual).to(equal("Cat:10"))
+  }
+
 }

apollo-ios-codegen/Sources/ApolloCodegenLib/Templates/InterfaceTemplate.swift

@@ -18,7 +18,15 @@ struct InterfaceTemplate: TemplateRenderer {
     """
     \(documentation: graphqlInterface.documentation, config: config)
     \(graphqlInterface.name.typeNameDocumentation)
-    static let \(graphqlInterface.render(as: .typename)) = \(config.ApolloAPITargetName).Interface(name: "\(graphqlInterface.name.schemaName)")
+    static let \(graphqlInterface.render(as: .typename)) = \(config.ApolloAPITargetName).Interface(name: "\(graphqlInterface.name.schemaName)", keyFields: \(KeyFieldsTemplate()))
+    """
+  }
+
+  private func KeyFieldsTemplate() -> TemplateString {
+    guard let fields = graphqlInterface.keyFields, !fields.isEmpty else { return "nil" }
+
+    return """
+    [\(list: fields.map { "\"\($0)\"" })]
     """
   }
 }

apollo-ios-codegen/Sources/GraphQLCompiler/GraphQLSchema.swift

@@ -279,16 +279,20 @@ public final class GraphQLInterfaceType: GraphQLAbstractType, GraphQLInterfaceIm
   public private(set) var fields: [String: GraphQLField]!
 
   public private(set) var interfaces: [GraphQLInterfaceType]!
+
+  public private(set) var keyFields: [String]!
 
   /// Initializer to be used for creating mock objects in tests only.
   init(
     name: GraphQLName,
     documentation: String?,
     fields: [String: GraphQLField],
-    interfaces: [GraphQLInterfaceType]
+    interfaces: [GraphQLInterfaceType],
+    keyFields: [String]
   ) {
     self.fields = fields
     self.interfaces = interfaces
+    self.keyFields = keyFields
     super.init(name: name, documentation: documentation)
   }
 
@@ -299,6 +303,7 @@ public final class GraphQLInterfaceType: GraphQLAbstractType, GraphQLInterfaceIm
   override func finalize(_ jsValue: JSValue, bridge: isolated JavaScriptBridge) {
     self.fields = try! bridge.invokeMethod("getFields", on: jsValue)
     self.interfaces = try! bridge.invokeMethod("getInterfaces", on: jsValue)
+    self.keyFields = jsValue["_apolloKeyFields"]
   }
 
   public override var debugDescription: String {

apollo-ios-codegen/Sources/GraphQLCompiler/JavaScript/src/__tests__/typePolicyDirectiveTests.ts

@@ -16,6 +16,10 @@ describe("given SDL without typePolicy", () => {
     allRectangles: [Rectangle!]
   }
 
+  interface Shape {
+    surface: Int!
+  }
+
   type Rectangle {
     width: Int!
     height: Int!
@@ -29,6 +33,9 @@ describe("given SDL without typePolicy", () => {
 
     const type = schema.getTypeMap()["Rectangle"] as ObjectWithMeta;
     expect(type._apolloKeyFields).toHaveLength(0);
+
+    const iface = schema.getTypeMap()["Shape"] as ObjectWithMeta;
+    expect(iface._apolloKeyFields).toHaveLength(0);
   });
 });
 
@@ -86,6 +93,10 @@ describe("given SDL with valid typePolicy", () => {
       const type = schema.getTypeMap()["Dog"] as ObjectWithMeta;
       expect(type._apolloKeyFields).toHaveLength(1);
       expect(type._apolloKeyFields).toContain("id");
+
+      const iface = schema.getTypeMap()["Animal"] as ObjectWithMeta;
+      expect(iface._apolloKeyFields).toHaveLength(1);
+      expect(iface._apolloKeyFields).toContain("id");
     });
   });
 

apollo-ios-codegen/Sources/GraphQLCompiler/JavaScript/src/utilities/typePolicyDirective.ts

@@ -170,7 +170,7 @@ export function addTypePolicyDirectivesToSchema(schema: GraphQLSchema) {
   for (const key in types) {
     const type = types[key];
 
-    if (type instanceof GraphQLObjectType) {
+    if (type instanceof GraphQLObjectType || type instanceof GraphQLInterfaceType) {
       (type as any)._apolloKeyFields = keyFieldsFor(type);
     }
   }

apollo-ios/Sources/Apollo/ExecutionSources/CacheDataExecutionSource.swift

@@ -72,7 +72,7 @@ struct CacheDataExecutionSource: GraphQLExecutionSource {
     return transaction.loadObject(forKey: reference.key)
   }
 
-  func computeCacheKey(for object: Record, in schema: any SchemaMetadata.Type) -> CacheKey? {
+  func computeCacheKey(for object: Record, in schema: any SchemaMetadata.Type, withInterface interface: Interface?) -> CacheKey? {
     return object.key
   }
 

apollo-ios/Sources/Apollo/GraphQLExecutionSource.swift

@@ -43,7 +43,7 @@ public protocol GraphQLExecutionSource {
   /// - Returns: A cache key for normalizing the object in the cache. If `nil` is returned the
   /// object is assumed to be stored in the cache with no normalization. The executor will
   /// construct a cache key based on the object's path in its enclosing operation.
-  func computeCacheKey(for object: RawObjectData, in schema: any SchemaMetadata.Type) -> CacheKey?
+  func computeCacheKey(for object: RawObjectData, in schema: any SchemaMetadata.Type, withInterface interface: Interface?) -> CacheKey?
 }
 
 /// A type of `GraphQLExecutionSource` that uses the user defined cache key computation
@@ -57,8 +57,8 @@ public protocol CacheKeyComputingExecutionSource: GraphQLExecutionSource {
 }
 
 extension CacheKeyComputingExecutionSource {
-  @_spi(Execution) public func computeCacheKey(for object: RawObjectData, in schema: any SchemaMetadata.Type) -> CacheKey? {
+  @_spi(Execution) public func computeCacheKey(for object: RawObjectData, in schema: any SchemaMetadata.Type, withInterface interface: Interface?) -> CacheKey? {
     let dataWrapper = opaqueObjectDataWrapper(for: object)
-    return schema.cacheKey(for: dataWrapper)
+    return schema.cacheKey(for: dataWrapper, withInterface: interface)
   }
 }

apollo-ios/Sources/Apollo/GraphQLExecutor.swift

@@ -493,9 +493,11 @@ public final class GraphQLExecutor<Source: GraphQLExecutionSource> {
     onChildObject object: Source.RawObjectData,
     accumulator: Accumulator
   ) -> PossiblyDeferred<Accumulator.PartialResult> {
+    let expectedInterface = rootSelectionSetType.__parentType as? Interface
+
     let (childExecutionInfo, selections) = fieldInfo.computeChildExecutionData(
       withRootType: rootSelectionSetType,
-      cacheKey: executionSource.computeCacheKey(for: object, in: fieldInfo.parentInfo.schema)
+      cacheKey: executionSource.computeCacheKey(for: object, in: fieldInfo.parentInfo.schema, withInterface: expectedInterface)
     )
 
     return execute(

apollo-ios/Sources/ApolloAPI/SchemaMetadata.swift

@@ -52,16 +52,17 @@ extension SchemaMetadata {
   /// for the `NormalizedCache`.
   ///
   /// - Parameter object: A ``JSONObject`` dictionary representing an object in a GraphQL response.
+  /// - Parameter interface: An optional ``Interface`` of the expected object.
   /// - Returns: A `String` representing the cache key for the `object` to be used by
   /// `NormalizedCache` mechanisms.
-  @inlinable public static func cacheKey(for object: ObjectData) -> String? {
+  @inlinable public static func cacheKey(for object: ObjectData, withInterface interface: Interface? = nil) -> String? {
     guard let type = graphQLType(for: object) else { return nil }
 
     if let info = configuration.cacheKeyInfo(for: type, object: object) {
       return "\(info.uniqueKeyGroup ?? type.typename):\(info.id)"
     }
 
-    guard let keyFields = type.keyFields else { return nil }
+    guard let keyFields = type.keyFields ?? interface?.keyFields else { return nil }
 
     let idValues = try? keyFields.map {
       guard let keyFieldValue = object[$0] else {

apollo-ios/Sources/ApolloAPI/SchemaTypes/Interface.swift

@@ -7,11 +7,21 @@
 public struct Interface: Hashable, Sendable {
   /// The name of the ``Interface`` in the GraphQL schema.
   public let name: String
+
+  /// A list of fields used to uniquely identify an instance of an object implementing this interface.
+  ///
+  /// This is set by adding a `@typePolicy` directive to the schema.
+  public let keyFields: [String]?
 
   /// Designated Initializer
   ///
   /// - Parameter name: The name of the ``Interface`` in the GraphQL schema.
-  public init(name: String) {
+  public init(name: String, keyFields: [String]? = nil) {
     self.name = name
+    if keyFields?.isEmpty == false {
+      self.keyFields = keyFields
+    } else {
+      self.keyFields = nil
+    }
   }
 }