Handle missing fields in readUpdatableQuery/Fragment

Summary:
# Why

* Currently, if one reads a field, like `node(id: 4)`, in a typesafe updater, if that linked field is undefined in the store, the user will receive `undefined`.
* This is true even if the user has provided a missing field handler that could provide that field.
* This is annoying, because it violates users' expectations.

# Fix

* In `createUpdatableProxy`, whenever a field is read and is undefined, we attempt to have missing field handlers provide that record.
* This requires passing the missing field handlers from where they are defined (e.g. on the environment) through to `RelayRecordSourceProxy`, etc.

Reviewed By: alunyov

Differential Revision:
D40840474

LaMa Project: L1125407

fbshipit-source-id: 66df283e67a079b82a392950ef316b4054a9e38e

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

@@ -17,6 +17,7 @@ import type {INetwork} from '../network/RelayNetworkTypes';
 import type RelayObservable from '../network/RelayObservable';
 import type {
   ExecuteMutationConfig,
+  MissingFieldHandler,
   LogFunction,
   MutationParameters,
   OperationAvailability,
@@ -54,6 +55,7 @@ export type ActorSpecificEnvironmentConfig = $ReadOnly<{
   network: INetwork,
   requiredFieldLogger: RequiredFieldLogger,
   store: Store,
+  missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>,
 }>;
 
 class ActorSpecificEnvironment implements IActorEnvironment {
@@ -83,6 +85,7 @@ class ActorSpecificEnvironment implements IActorEnvironment {
       config.store,
       config.handlerProvider,
       defaultGetDataID,
+      config.missingFieldHandlers,
     );
     this._defaultRenderPolicy = config.defaultRenderPolicy;
     // TODO:T92305692 Remove `options` in favor of directly using `actorIdentifier` on the environment

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

@@ -83,7 +83,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
   +_handlerProvider: HandlerProvider;
   +_isServer: boolean;
   +_logFn: LogFunction;
-  +_missingFieldHandlers: ?$ReadOnlyArray<MissingFieldHandler>;
+  +_missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>;
   +_operationExecutions: Map<string, ActiveState>;
   +_operationLoader: ?OperationLoader;
   +_reactFlightPayloadDeserializer: ?ReactFlightPayloadDeserializer;
@@ -109,7 +109,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
     this._shouldProcessClientComponents = config.shouldProcessClientComponents;
     this._treatMissingFieldsAsNull = config.treatMissingFieldsAsNull ?? false;
     this._isServer = config.isServer ?? false;
-    this._missingFieldHandlers = config.missingFieldHandlers;
+    this._missingFieldHandlers = config.missingFieldHandlers ?? [];
     this._createStoreForActor = config.createStoreForActor;
     this._reactFlightPayloadDeserializer =
       config.reactFlightPayloadDeserializer;
@@ -141,6 +141,7 @@ class MultiActorEnvironment implements IMultiActorEnvironment {
         network: this._createNetworkForActor(actorIdentifier),
         handlerProvider: this._handlerProvider,
         defaultRenderPolicy: this._defaultRenderPolicy,
+        missingFieldHandlers: this._missingFieldHandlers,
       });
       this._actorEnvironments.set(actorIdentifier, newEnvironment);
       return newEnvironment;

packages/relay-runtime/mutations/RelayRecordSourceProxy.js

@@ -22,6 +22,7 @@ import type {
   RecordSource,
   RecordSourceProxy,
   UpdatableData,
+  MissingFieldHandler,
 } from '../store/RelayStoreTypes';
 import type {
   DataID,
@@ -55,18 +56,21 @@ class RelayRecordSourceProxy implements RecordSourceProxy {
   _getDataID: GetDataID;
   _invalidatedStore: boolean;
   _idsMarkedForInvalidation: DataIDSet;
+  _missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>;
 
   constructor(
     mutator: RelayRecordSourceMutator,
     getDataID: GetDataID,
     handlerProvider?: ?HandlerProvider,
+    missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>,
   ) {
     this.__mutator = mutator;
     this._handlerProvider = handlerProvider || null;
     this._proxies = {};
     this._getDataID = getDataID;
     this._invalidatedStore = false;
     this._idsMarkedForInvalidation = new Set();
+    this._missingFieldHandlers = missingFieldHandlers;
   }
 
   publishSource(
@@ -176,7 +180,12 @@ class RelayRecordSourceProxy implements RecordSourceProxy {
     query: UpdatableQuery<TVariables, TData>,
     variables: TVariables,
   ): UpdatableData<TData> {
-    return readUpdatableQuery_EXPERIMENTAL(query, variables, this);
+    return readUpdatableQuery_EXPERIMENTAL(
+      query,
+      variables,
+      this,
+      this._missingFieldHandlers,
+    );
   }
 
   readUpdatableFragment_EXPERIMENTAL<TFragmentType: FragmentType, TData>(
@@ -187,6 +196,7 @@ class RelayRecordSourceProxy implements RecordSourceProxy {
       fragment,
       fragmentReference,
       this,
+      this._missingFieldHandlers,
     );
   }
 }

packages/relay-runtime/mutations/RelayRecordSourceSelectorProxy.js

@@ -17,6 +17,7 @@ import type {
   RecordProxy,
   RecordSourceProxy,
   RecordSourceSelectorProxy,
+  MissingFieldHandler,
   SingularReaderSelector,
   UpdatableData,
 } from '../store/RelayStoreTypes';
@@ -50,15 +51,18 @@ class RelayRecordSourceSelectorProxy implements RecordSourceSelectorProxy {
   __mutator: RelayRecordSourceMutator;
   __recordSource: RecordSourceProxy;
   _readSelector: SingularReaderSelector;
+  _missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>;
 
   constructor(
     mutator: RelayRecordSourceMutator,
     recordSource: RecordSourceProxy,
     readSelector: SingularReaderSelector,
+    missingFieldHandlers: $ReadOnlyArray<MissingFieldHandler>,
   ) {
     this.__mutator = mutator;
     this.__recordSource = recordSource;
     this._readSelector = readSelector;
+    this._missingFieldHandlers = missingFieldHandlers;
   }
 
   create(dataID: DataID, typeName: string): RecordProxy {
@@ -136,7 +140,12 @@ class RelayRecordSourceSelectorProxy implements RecordSourceSelectorProxy {
     query: UpdatableQuery<TVariables, TData>,
     variables: TVariables,
   ): UpdatableData<TData> {
-    return readUpdatableQuery_EXPERIMENTAL(query, variables, this);
+    return readUpdatableQuery_EXPERIMENTAL(
+      query,
+      variables,
+      this,
+      this._missingFieldHandlers,
+    );
   }
 
   readUpdatableFragment_EXPERIMENTAL<TFragmentType: FragmentType, TData>(
@@ -147,6 +156,7 @@ class RelayRecordSourceSelectorProxy implements RecordSourceSelectorProxy {
       fragment,
       fragmentReference,
       this,
+      this._missingFieldHandlers,
     );
   }
 }

packages/relay-runtime/mutations/__tests__/RelayRecordSourceProxy-test.js

@@ -74,7 +74,12 @@ describe('RelayRecordSourceProxy', () => {
     baseSource = new RelayRecordSource(simpleClone(initialData));
     sinkSource = new RelayRecordSource({});
     mutator = new RelayRecordSourceMutator(baseSource, sinkSource);
-    store = new RelayRecordSourceProxy(mutator, defaultGetDataID);
+    store = new RelayRecordSourceProxy(
+      mutator,
+      defaultGetDataID,
+      undefined,
+      [],
+    );
   });
 
   describe('get()', () => {