Improve error message when you mix up @LiVe and non-live values.

Reviewed By: alunyov

Differential Revision: D37732332

fbshipit-source-id: dc6056a3ba4054c08bc1f7d87a95b8f8b4833d06

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

@@ -1193,3 +1193,63 @@ describe.each([
     expect(renderer.toJSON()).toBe('Loading...');
   });
 });
+
+test('Errors when reading a @live resolver that does not return a LiveState object', () => {
+  const source = RelayRecordSource.create({
+    'client:root': {
+      __id: 'client:root',
+      __typename: '__Root',
+    },
+  });
+  const FooQuery = graphql`
+    query LiveResolversTest16Query {
+      live_resolver_with_bad_return_value
+    }
+  `;
+
+  const operation = createOperationDescriptor(FooQuery, {});
+  const store = new LiveResolverStore(source, {
+    gcReleaseBufferSize: 0,
+  });
+
+  const environment = new RelayModernEnvironment({
+    network: RelayNetwork.create(jest.fn()),
+    store,
+  });
+
+  expect(() => {
+    environment.lookup(operation.fragment);
+  }).toThrow(
+    'Expected the @live Relay Resolver backing the field "live_resolver_with_bad_return_value" to return a value that implements LiveState. Did you mean to remove the @live annotation on this resolver?',
+  );
+});
+
+test('Errors when reading a non-@live resolver that returns a LiveState object', () => {
+  const source = RelayRecordSource.create({
+    'client:root': {
+      __id: 'client:root',
+      __typename: '__Root',
+    },
+  });
+  const FooQuery = graphql`
+    query LiveResolversTest17Query {
+      non_live_resolver_with_live_return_value
+    }
+  `;
+
+  const operation = createOperationDescriptor(FooQuery, {});
+  const store = new LiveResolverStore(source, {
+    gcReleaseBufferSize: 0,
+  });
+
+  const environment = new RelayModernEnvironment({
+    network: RelayNetwork.create(jest.fn()),
+    store,
+  });
+
+  expect(() => {
+    environment.lookup(operation.fragment);
+  }).toThrow(
+    'Unexpected LiveState value retuned from the non-@live Relay Resolver backing the field "non_live_resolver_with_live_return_value". Did you intend to add @live to this resolver?.',
+  );
+});

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

@@ -0,0 +1,29 @@
+/**
+ * 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
+ * @emails oncall+relay
+ */
+
+'use strict';
+
+/**
+ * @RelayResolver
+ * @fieldName live_resolver_with_bad_return_value
+ * @onType Query
+ * @live
+ *
+ * A @live resolver that does not return a LiveObject
+ */
+import type {LiveState} from '../../experimental-live-resolvers/LiveResolverStore';
+
+function liveResolverWithBadReturnValue(): LiveState<string> {
+  // $FlowFixMe The purpose of this resolver is to test a bad return value.
+  return 'Oops!';
+}
+
+module.exports = liveResolverWithBadReturnValue;

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

@@ -0,0 +1,34 @@
+/**
+ * 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
+ * @emails oncall+relay
+ */
+
+'use strict';
+
+/**
+ * @RelayResolver
+ * @fieldName non_live_resolver_with_live_return_value
+ * @onType Query
+ *
+ * A non-@live resolver that returns a LiveObject
+ */
+import type {LiveState} from '../../experimental-live-resolvers/LiveResolverStore';
+
+function nonLiveResolverWithLiveReturnValue(): LiveState<string> {
+  return {
+    read() {
+      return 'Oops!';
+    },
+    subscribe(cb) {
+      return () => {};
+    },
+  };
+}
+
+module.exports = nonLiveResolverWithLiveReturnValue;

packages/relay-runtime/store/experimental-live-resolvers/LiveResolverCache.js

@@ -27,6 +27,7 @@ import type {
   GetDataForResolverFragmentFn,
   ResolverCache,
 } from '../ResolverCache';
+import type LiveResolverStore from './LiveResolverStore';
 import type {LiveState} from './LiveResolverStore';
 
 const recycleNodesInto = require('../../util/recycleNodesInto');
@@ -41,7 +42,6 @@ const {
   RELAY_RESOLVER_VALUE_KEY,
   getStorageKey,
 } = require('../RelayStoreUtils');
-const LiveResolverStore = require('./LiveResolverStore');
 const {isSuspenseSentinel} = require('./LiveResolverSuspenseSentinel');
 const invariant = require('invariant');
 const warning = require('warning');
@@ -129,7 +129,9 @@ class LiveResolverCache implements ResolverCache {
           if (__DEV__) {
             invariant(
               isLiveStateValue(evaluationResult.resolverResult),
-              'Expected a @live Relay Resolver to return a value that implements LiveState.',
+              'Expected the @live Relay Resolver backing the field "%s" to return a value ' +
+                'that implements LiveState. Did you mean to remove the @live annotation on this resolver?',
+              field.path,
             );
           }
           const liveState: LiveState<mixed> =
@@ -138,6 +140,13 @@ class LiveResolverCache implements ResolverCache {
           this._setLiveStateValue(linkedRecord, linkedID, liveState);
         }
       } else {
+        if (__DEV__) {
+          invariant(
+            !isLiveStateValue(evaluationResult.resolverResult),
+            'Unexpected LiveState value retuned from the non-@live Relay Resolver backing the field "%s". Did you intend to add @live to this resolver?.',
+            field.path,
+          );
+        }
         RelayModernRecord.setValue(
           linkedRecord,
           RELAY_RESOLVER_VALUE_KEY,