Revert to skipping missing types

federation-js/src/composition/compose.ts

@@ -48,7 +48,7 @@ import {
 import { validateSDL } from 'graphql/validation/validate';
 import { compositionRules } from './rules';
 import { printSupergraphSdl } from '../service/printSupergraphSdl';
-import { mapGetOrSet, mapValues, filterMap } from '../utilities';
+import { mapGetOrSet, mapValues } from '../utilities';
 
 const EmptyQueryDefinition = {
   kind: Kind.OBJECT_TYPE_DEFINITION,
@@ -677,7 +677,12 @@ export function addFederationMetadataToSchemaNodes({
   }
 
   for (const [typeName, fieldsToDirectivesMap] of typeNameToFieldDirectivesMap.entries()) {
-    const type = schema.getType(typeName) as GraphQLObjectType;
+    // It's plausible we're dealing with an incomplete schema here which might not
+    // account for all the types we saw when inspecting SDL. In the case that a
+    // type is extended with no base definition anywhere, it won't exist in the schema.
+    // There will be relevant composition errors for that case.
+    const type = schema.getType(typeName) as GraphQLObjectType | undefined;
+    if (!type) continue;
 
     for (const [
       fieldName,
@@ -762,22 +767,14 @@ export function composeServices(services: ServiceDefinition[]): CompositionResul
 
   schema = lexicographicSortSchema(schema);
 
-  // Now that we have a constructed schema, we can filter this map based on types
-  // that made it into the schema successfully. Types that didn't make it into the
-  // schema will have related composition errors.
-  const filteredTypeNameToFieldDirectivesMap = filterMap(
-    typeNameToFieldDirectivesMap,
-    (typeName) => !!schema.getType(typeName),
-  );
-
   addFederationMetadataToSchemaNodes({
     schema,
     typeToServiceMap,
     externalFields,
     keyDirectivesMap,
     valueTypes,
     directiveDefinitionsMap,
-    typeNameToFieldDirectivesMap: filteredTypeNameToFieldDirectivesMap,
+    typeNameToFieldDirectivesMap,
   });
 
   if (errors.length > 0) {

federation-js/src/utilities/index.ts

@@ -2,4 +2,3 @@ export { assert } from './assert';
 export { isNotNullOrUndefined } from './isNotNullOrUndefined';
 export { mapGetOrSet } from './mapGetOrSet';
 export { mapValues } from './mapValues';
-export { filterMap } from './filterMap';