Allow missing fields from defer payloads

packages/relay-runtime/multi-actor-environment/MultiActorEnvironment.js

@@ -71,6 +71,7 @@ export type MultiActorEnvironmentConfig = $ReadOnly<{
   scheduler?: ?TaskScheduler,
   shouldProcessClientComponents?: ?boolean,
   treatMissingFieldsAsNull?: boolean,
+  deferDeduplicatedFields?: boolean,
 }>;
 
 class MultiActorEnvironment implements IMultiActorEnvironment {
@@ -91,6 +92,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
   +_scheduler: ?TaskScheduler;
   +_shouldProcessClientComponents: ?boolean;
   +_treatMissingFieldsAsNull: boolean;
+  +_deferDeduplicatedFields: boolean;
 
   constructor(config: MultiActorEnvironmentConfig) {
     this._actorEnvironments = new Map();
@@ -106,6 +108,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
     this._relayFieldLogger = config.relayFieldLogger ?? defaultRelayFieldLogger;
     this._shouldProcessClientComponents = config.shouldProcessClientComponents;
     this._treatMissingFieldsAsNull = config.treatMissingFieldsAsNull ?? false;
+    this._deferDeduplicatedFields = config.deferDeduplicatedFields ?? false;
     this._isServer = config.isServer ?? false;
     this._missingFieldHandlers = config.missingFieldHandlers ?? [];
     this._createStoreForActor = config.createStoreForActor;
@@ -471,6 +474,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
           return this.forActor(actorIdentifier).getStore();
         },
         treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
+        deferDeduplicatedFields: this._deferDeduplicatedFields,
         updater,
         log: this._logFn,
         normalizeResponse: this._normalizeResponse,

packages/relay-runtime/store/OperationExecutor.js

@@ -88,6 +88,7 @@ export type ExecuteConfig<TMutation: MutationParameters> = {
   +sink: Sink<GraphQLResponse>,
   +source: RelayObservable<GraphQLResponse>,
   +treatMissingFieldsAsNull: boolean,
+  +deferDeduplicatedFields: boolean,
   +updater?: ?SelectorStoreUpdater<TMutation['response']>,
   +log: LogFunction,
 };
@@ -127,6 +128,7 @@ class Executor<TMutation: MutationParameters> {
   _actorIdentifier: ActorIdentifier;
   _getDataID: GetDataID;
   _treatMissingFieldsAsNull: boolean;
+  _deferDeduplicatedFields: boolean;
   _incrementalPayloadsPending: boolean;
   _incrementalResults: Map<Label, Map<PathKey, IncrementalResults>>;
   _log: LogFunction;
@@ -177,13 +179,15 @@ class Executor<TMutation: MutationParameters> {
     sink,
     source,
     treatMissingFieldsAsNull,
+    deferDeduplicatedFields,
     updater,
     log,
     normalizeResponse,
   }: ExecuteConfig<TMutation>): void {
     this._actorIdentifier = actorIdentifier;
     this._getDataID = getDataID;
     this._treatMissingFieldsAsNull = treatMissingFieldsAsNull;
+    this._deferDeduplicatedFields = deferDeduplicatedFields;
     this._incrementalPayloadsPending = false;
     this._incrementalResults = new Map();
     this._log = log;
@@ -660,6 +664,7 @@ class Executor<TMutation: MutationParameters> {
           path: [],
           shouldProcessClientComponents: this._shouldProcessClientComponents,
           treatMissingFieldsAsNull,
+          deferDeduplicatedFields: false,
         },
         this._useExecTimeResolvers,
       );
@@ -778,6 +783,7 @@ class Executor<TMutation: MutationParameters> {
         path: followupPayload.path,
         treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
         shouldProcessClientComponents: this._shouldProcessClientComponents,
+        deferDeduplicatedFields: false,
       },
       this._useExecTimeResolvers,
     );
@@ -862,6 +868,7 @@ class Executor<TMutation: MutationParameters> {
           path: [],
           treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
           shouldProcessClientComponents: this._shouldProcessClientComponents,
+          deferDeduplicatedFields: false,
         },
         this._useExecTimeResolvers,
       );
@@ -1327,6 +1334,7 @@ class Executor<TMutation: MutationParameters> {
         log: this._log,
         path: placeholder.path,
         treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
+        deferDeduplicatedFields: this._deferDeduplicatedFields,
         shouldProcessClientComponents: this._shouldProcessClientComponents,
       },
       this._useExecTimeResolvers,
@@ -1560,6 +1568,7 @@ class Executor<TMutation: MutationParameters> {
         log: this._log,
         path: [...normalizationPath, responseKey, String(itemIndex)],
         treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
+        deferDeduplicatedFields: false,
         shouldProcessClientComponents: this._shouldProcessClientComponents,
       },
       this._useExecTimeResolvers,

packages/relay-runtime/store/RelayModernEnvironment.js

@@ -67,6 +67,7 @@ export type EnvironmentConfig = {
   +configName?: string,
   +handlerProvider?: ?HandlerProvider,
   +treatMissingFieldsAsNull?: boolean,
+  +deferDeduplicatedFields?: boolean,
   +log?: ?LogFunction,
   +operationLoader?: ?OperationLoader,
   +network: INetwork,
@@ -97,6 +98,7 @@ class RelayModernEnvironment implements IEnvironment {
   _operationTracker: OperationTracker;
   _getDataID: GetDataID;
   _treatMissingFieldsAsNull: boolean;
+  _deferDeduplicatedFields: boolean;
   _operationExecutions: Map<string, ActiveState>;
   +options: mixed;
   +_isServer: boolean;
@@ -106,6 +108,7 @@ class RelayModernEnvironment implements IEnvironment {
   constructor(config: EnvironmentConfig) {
     this.configName = config.configName;
     this._treatMissingFieldsAsNull = config.treatMissingFieldsAsNull === true;
+    this._deferDeduplicatedFields = config.deferDeduplicatedFields === true;
     const operationLoader = config.operationLoader;
     if (__DEV__) {
       if (operationLoader != null) {
@@ -500,6 +503,7 @@ class RelayModernEnvironment implements IEnvironment {
           return store;
         },
         treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
+        deferDeduplicatedFields: this._deferDeduplicatedFields,
         updater,
         normalizeResponse: this._normalizeResponse,
       });

packages/relay-runtime/store/RelayModernStore.js

@@ -115,6 +115,7 @@ class RelayModernStore implements Store {
   _resolverContext: ?ResolverContext;
   _actorIdentifier: ?ActorIdentifier;
   _treatMissingFieldsAsNull: boolean;
+  _deferDeduplicatedFields: boolean;
 
   constructor(
     source: MutableRecordSource,
@@ -134,6 +135,7 @@ class RelayModernStore implements Store {
       // These additional config options are only used if the experimental
       // @outputType resolver feature is used
       treatMissingFieldsAsNull?: ?boolean,
+      deferDeduplicatedFields?: ?boolean,
       actorIdentifier?: ?ActorIdentifier,
     },
   ) {
@@ -182,6 +184,7 @@ class RelayModernStore implements Store {
       options?.shouldProcessClientComponents ?? false;
 
     this._treatMissingFieldsAsNull = options?.treatMissingFieldsAsNull ?? false;
+    this._deferDeduplicatedFields = options?.deferDeduplicatedFields ?? false;
     this._actorIdentifier = options?.actorIdentifier;
 
     initializeRecordSource(this._recordSource);
@@ -827,6 +830,7 @@ class RelayModernStore implements Store {
       getDataID: this._getDataID,
       log: this.__log,
       treatMissingFieldsAsNull: this._treatMissingFieldsAsNull,
+      deferDeduplicatedFields: this._deferDeduplicatedFields,
       shouldProcessClientComponents: this._shouldProcessClientComponents,
       actorIdentifier: this._actorIdentifier,
     };

packages/relay-runtime/store/RelayResponseNormalizer.js

@@ -76,6 +76,7 @@ export type GetDataID = (
 export type NormalizationOptions = {
   +getDataID: GetDataID,
   +treatMissingFieldsAsNull: boolean,
+  +deferDeduplicatedFields: boolean,
   +log: ?LogFunction,
   +path?: $ReadOnlyArray<string>,
   +shouldProcessClientComponents?: ?boolean,
@@ -114,6 +115,7 @@ class RelayResponseNormalizer {
   _getDataId: GetDataID;
   _handleFieldPayloads: Array<HandleFieldPayload>;
   _treatMissingFieldsAsNull: boolean;
+  _deferDeduplicatedFields: boolean;
   _incrementalPlaceholders: Array<IncrementalDataPlaceholder>;
   _isClientExtension: boolean;
   _isUnmatchedAbstractType: boolean;
@@ -136,6 +138,7 @@ class RelayResponseNormalizer {
     this._getDataId = options.getDataID;
     this._handleFieldPayloads = [];
     this._treatMissingFieldsAsNull = options.treatMissingFieldsAsNull;
+    this._deferDeduplicatedFields = options.deferDeduplicatedFields;
     this._incrementalPlaceholders = [];
     this._isClientExtension = false;
     this._isUnmatchedAbstractType = false;
@@ -525,7 +528,9 @@ class RelayResponseNormalizer {
         // client is assumed to be correctly configured with
         // treatMissingFieldsAsNull=true.
         const isOptionalField =
-          this._isClientExtension || this._isUnmatchedAbstractType;
+          this._isClientExtension ||
+          this._isUnmatchedAbstractType ||
+          this._deferDeduplicatedFields;
 
         if (isOptionalField) {
           // Field not expected to exist regardless of whether the server is pruning null

packages/relay-runtime/store/__tests__/RelayExperimentalGraphResponseHandler-test.js

@@ -30,6 +30,7 @@ const {getRequest} = require('relay-runtime/query/GraphQLTag');
 const defaultOptions = {
   getDataID: defaultGetDataID,
   treatMissingFieldsAsNull: false,
+  deferDeduplicatedFields: false,
   log: null,
 };
 

packages/relay-runtime/store/__tests__/RelayExperimentalGraphResponseTransform-test.js

@@ -32,6 +32,7 @@ const {ROOT_ID} = require('relay-runtime/store/RelayStoreUtils');
 const defaultOptions = {
   getDataID: defaultGetDataID,
   treatMissingFieldsAsNull: false,
+  deferDeduplicatedFields: false,
   log: null,
 };
 

packages/relay-runtime/store/__tests__/RelayModernEnvironment-ExecuteWithDefer-test.js

@@ -312,6 +312,90 @@ describe.each(['RelayModernEnvironment', 'MultiActorEnvironment'])(
         });
       });
 
+      it('processes deferred payloads with deduplicated fields', () => {
+        // This functionality prevents Relay from throwing an error when missing
+        // fields are received in a deferred response. This is required for the
+        // latest `@defer` spec proposal, which does not send duplicate fields
+        // in deferred responses. While Relay does not yet attempt to support the latest
+        // spec proposal (https://github.com/graphql/defer-stream-wg/discussions/69),
+        // this option allows users to transform responses into a format that Relay
+        // can accept.
+        environment = new RelayModernEnvironment({
+          network: RelayNetwork.create(fetch),
+          store,
+          handlerProvider,
+          deferDeduplicatedFields: true,
+        });
+
+        query = graphql`
+          query RelayModernEnvironmentExecuteWithDeferTestUserOverlappingFieldsQuery(
+            $id: ID!
+          ) {
+            node(id: $id) {
+              ... on User {
+                id
+                name
+                ...RelayModernEnvironmentExecuteWithDeferTestUserOverlappingFieldsFragment
+                  @dangerously_unaliased_fixme
+                  @defer(label: "UserFragment")
+              }
+            }
+          }
+        `;
+        fragment = graphql`
+          fragment RelayModernEnvironmentExecuteWithDeferTestUserOverlappingFieldsFragment on User {
+            name
+            alternate_name
+          }
+        `;
+
+        variables = {id: '1'};
+        operation = createOperationDescriptor(query, variables);
+        selector = createReaderSelector(fragment, '1', {}, operation.request);
+
+        const initialSnapshot = environment.lookup(selector);
+        const callback = jest.fn<[Snapshot], void>();
+        environment.subscribe(initialSnapshot, callback);
+
+        environment.execute({operation}).subscribe(callbacks);
+        dataSource.next({
+          data: {
+            node: {
+              __typename: 'User',
+              id: '1',
+              name: 'joe',
+            },
+          },
+        });
+
+        jest.runAllTimers();
+        next.mockClear();
+        callback.mockClear();
+
+        dataSource.next({
+          data: {
+            alternate_name: 'joe2',
+          },
+          label:
+            'RelayModernEnvironmentExecuteWithDeferTestUserOverlappingFieldsQuery$defer$UserFragment',
+          path: ['node'],
+          extensions: {
+            is_final: true,
+          },
+        });
+
+        expect(complete).toBeCalledTimes(0);
+        expect(error).toBeCalledTimes(0);
+        expect(next).toBeCalledTimes(1);
+        expect(callback).toBeCalledTimes(1);
+        const snapshot = callback.mock.calls[0][0];
+        expect(snapshot.isMissingData).toBe(false);
+        expect(snapshot.data).toEqual({
+          name: 'joe',
+          alternate_name: 'joe2',
+        });
+      });
+
       describe('Query with exec time resolvers', () => {
         let resolverOperation;
         beforeEach(() => {