chore: typescript-redux followups

query-planner-js/src/buildQueryPlan.ts

@@ -52,7 +52,11 @@ import {
 } from './QueryPlan';
 import { getFieldDef, getResponseName } from './utilities/graphql';
 import { MultiMap } from './utilities/MultiMap';
-import { getFederationMetadataForType, getFederationMetadataForField } from './composedSchema';
+import {
+  getFederationMetadataForType,
+  getFederationMetadataForField,
+  isValueTypeMetadata,
+} from './composedSchema';
 import { DebugLogger } from './utilities/debug';
 
 
@@ -1136,7 +1140,8 @@ export class QueryPlanningContext {
   }
 
   getBaseService(parentType: GraphQLObjectType): string | undefined {
-    return getFederationMetadataForType(parentType)?.graphName;
+    const type = getFederationMetadataForType(parentType);
+    return (type && !isValueTypeMetadata(type)) ? type.graphName : undefined;
   }
 
   getOwningService(
@@ -1170,7 +1175,11 @@ export class QueryPlanningContext {
     });
 
     for (const possibleType of this.getPossibleTypes(parentType)) {
-      const keys = getFederationMetadataForType(possibleType)?.keys?.get(serviceName);
+      const type = getFederationMetadataForType(possibleType);
+      const keys =
+        type && !isValueTypeMetadata(type)
+          ? type.keys.get(serviceName)
+          : undefined;
 
       if (!(keys && keys.length > 0)) continue;
 

query-planner-js/src/composedSchema/buildComposedSchema.ts

@@ -21,8 +21,10 @@ import { MultiMap } from '../utilities/MultiMap';
 import {
   FederationFieldMetadata,
   FederationTypeMetadata,
+  FederationEntityTypeMetadata,
   FieldSet,
   GraphMap,
+  isValueTypeMetadata,
 } from './metadata';
 
 export function buildComposedSchema(document: DocumentNode): GraphQLSchema {
@@ -148,8 +150,11 @@ export function buildComposedSchema(document: DocumentNode): GraphQLSchema {
       type.astNode,
     );
 
+    // The assertion here guarantees the safety of the type cast below
+    // (typeMetadata as FederationEntityTypeMetadata). Adjustments to this assertion
+    // should account for this dependency.
     assert(
-      !(typeMetadata.isValueType && typeDirectivesArgs.length >= 1),
+      !(isValueTypeMetadata(typeMetadata) && typeDirectivesArgs.length >= 1),
       `GraphQL type "${type.name}" cannot have a @${typeDirective.name} \
 directive without an @${ownerDirective.name} directive`,
     );
@@ -159,7 +164,12 @@ directive without an @${ownerDirective.name} directive`,
 
       const keyFields = parseFieldSet(typeDirectiveArgs['key']);
 
-      typeMetadata.keys?.add(graphName, keyFields);
+      // We know we won't actually be looping here in the case of a value type
+      // based on the assertion above, but TS is not able to infer that.
+      (typeMetadata as FederationEntityTypeMetadata).keys.add(
+        graphName,
+        keyFields,
+      );
     }
 
     for (const fieldDef of Object.values(type.getFields())) {

query-planner-js/src/composedSchema/metadata.ts

@@ -43,10 +43,25 @@ export type GraphMap = { [graphName: string]: Graph };
 export interface FederationSchemaMetadata {
   graphs: GraphMap;
 }
-export interface FederationTypeMetadata {
-  graphName?: GraphName;
-  keys?: MultiMap<GraphName, FieldSet>;
-  isValueType: boolean;
+
+export type FederationTypeMetadata =
+  | FederationEntityTypeMetadata
+  | FederationValueTypeMetadata;
+
+export interface FederationEntityTypeMetadata {
+  graphName: GraphName;
+  keys: MultiMap<GraphName, FieldSet>,
+  isValueType: false;
+}
+
+interface FederationValueTypeMetadata {
+  isValueType: true;
+}
+
+export function isValueTypeMetadata(
+  metadata: FederationTypeMetadata,
+): metadata is FederationValueTypeMetadata {
+  return metadata.isValueType;
 }
 
 export interface FederationFieldMetadata {