Return an interface with multiple weak concrete types from a resolver…

… field

Reviewed By: captbaritone

Differential Revision: D56438692

fbshipit-source-id: 12a4a029004f0b17cc71f6919f19597a63824afe

packages/react-relay/__tests__/RelayResolverInterface-test.js

@@ -263,6 +263,45 @@ describe.each([
   },
 );
 
+describe.each([
+  {
+    animalType: 'Octopus',
+    numLegs: '8',
+  },
+  {
+    animalType: 'PurpleOctopus',
+    numLegs: '8',
+  },
+])(
+  'resolvers can return an interface where all implementors are weak model types: %s',
+  ({animalType, numLegs}) => {
+    function WeakAnimalLegsQueryComponent(props: {request: {ofType: string}}) {
+      const data = useClientQuery(
+        graphql`
+          query RelayResolverInterfaceTestWeakAnimalLegsQuery(
+            $request: WeakAnimalRequest!
+          ) {
+            weak_animal(request: $request) {
+              ...RelayResolverInterfaceTestWeakAnimalLegsFragment
+            }
+          }
+        `,
+        {request: props.request},
+      );
+      return <WeakAnimalLegsFragmentComponent animal={data.weak_animal} />;
+    }
+
+    test(`should read the legs of a ${animalType}`, () => {
+      const animalRenderer = TestRenderer.create(
+        <EnvironmentWrapper environment={environment}>
+          <WeakAnimalLegsQueryComponent request={{ofType: animalType}} />
+        </EnvironmentWrapper>,
+      );
+      expect(animalRenderer.toJSON()).toEqual(numLegs);
+    });
+  },
+);
+
 test('resolvers can return a list of interfaces where all implementors are strong model types', () => {
   function AnimalsLegsQueryComponent(props: {
     requests: Array<{ofType: string, returnValidID: boolean}>,

packages/relay-runtime/store/__tests__/resolvers/WeakAnimalQueryResolvers.js

@@ -0,0 +1,54 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict-local
+ * @oncall relay
+ */
+
+import type {Query__weak_animal$normalization} from 'relay-runtime/store/__tests__/resolvers/__generated__/Query__weak_animal$normalization.graphql';
+
+/**
+ * Returns a single `IWeakAnimal` of a given type.
+ *
+ * @RelayResolver Query.weak_animal(request: WeakAnimalRequest!): IWeakAnimal
+ */
+function weak_animal(args: {
+  request: {ofType: string},
+}): Query__weak_animal$normalization {
+  switch (args.request.ofType) {
+    case 'Octopus':
+      return {
+        __relay_model_instance: {},
+        __typename: 'Octopus',
+      };
+    case 'PurpleOctopus':
+      return {
+        __relay_model_instance: {},
+        __typename: 'PurpleOctopus',
+      };
+    default:
+      throw new Error('Invalid type');
+  }
+}
+
+/**
+ * Returns a list of `IWeakAnimal` of a given type.
+ *
+ * @RelayResolver Query.weak_animals(requests: [WeakAnimalRequest!]!): [IWeakAnimal]
+ */
+function weak_animals(args: {
+  requests: $ReadOnlyArray<{ofType: string}>,
+}): Array<Query__weak_animal$normalization> {
+  return args.requests.map(request => {
+    return weak_animal({request});
+  });
+}
+
+module.exports = {
+  weak_animal,
+  weak_animals,
+};