feat(federation): Use extensions instead of custom federation objects (apollographql/apollo-server#4313)

Note: BREAKING CHANGE
In order to guarantee the safe usage of extensions, we must now
require `graphql@>14.5.0`. As such, we've narrowed the range in
federation and gateway's `peerDependencies`.

Composition in its current form modifies the graphql-js types in
order to accommodate some additional metadata required during
composition, validation, query planning, and execution. This is
no longer required due to the addition of 'extensions', which
this is intended to be used exactly for.

This commit transitions our usages of these custom metadata
objects into the extensions object where they belong.
Apollo-Orig-Commit-AS: apollographql/apollo-server@39e678c

Author: trevor-scheer

federation-js/CHANGELOG.md

@@ -13,6 +13,7 @@
 ## 0.16.10
 
 - The default branch of the repository has been changed to `main`.  As this changed a number of references in the repository's `package.json` and `README.md` files (e.g., for badges, links, etc.), this necessitates a release to publish those changes to npm. [PR #4302](https://github.com/apollographql/apollo-server/pull/4302)
+- __BREAKING__: Move federation metadata from custom objects on schema nodes over to the `extensions` field on schema nodes which are intended for metadata. This is a breaking change because it narrows the `graphql` peer dependency from `^14.0.2` to `^14.5.0` which is when [`extensions` were introduced](https://github.com/graphql/graphql-js/pull/2097) for all Type System objects. [PR #4302](https://github.com/apollographql/apollo-server/pull/4313)
 
 ## 0.16.9
 

federation-js/package.json

@@ -20,6 +20,6 @@
     "lodash.xorby": "^4.7.0"
   },
   "peerDependencies": {
-    "graphql": "^14.0.2 || ^15.0.0"
+    "graphql": "^14.5.0 || ^15.0.0"
   }
 }

federation-js/src/composition/__tests__/compose.test.ts

@@ -11,6 +11,7 @@ import {
   selectionSetSerializer,
 } from '../../snapshotSerializers';
 import { normalizeTypeDefs } from '../normalize';
+import { getFederationMetadata } from '../utils';
 
 expect.addSnapshotSerializer(astSerializer);
 expect.addSnapshotSerializer(typeSerializer);
@@ -59,8 +60,8 @@ describe('composeServices', () => {
     const product = schema.getType('Product') as GraphQLObjectType;
     const user = schema.getType('User') as GraphQLObjectType;
 
-    expect(product.federation.serviceName).toEqual('serviceA');
-    expect(user.federation.serviceName).toEqual('serviceB');
+    expect(getFederationMetadata(product).serviceName).toEqual('serviceA');
+    expect(getFederationMetadata(user).serviceName).toEqual('serviceB');
   });
 
   it("doesn't leave federation directives in the final schema", () => {
@@ -115,8 +116,8 @@ describe('composeServices', () => {
 
       const product = schema.getType('Product') as GraphQLObjectType;
 
-      expect(product.federation.serviceName).toEqual('serviceA');
-      expect(product.getFields()['price'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product).serviceName).toEqual('serviceA');
+      expect(getFederationMetadata(product.getFields()['price']).serviceName).toEqual(
         'serviceB',
       );
     });
@@ -154,8 +155,8 @@ describe('composeServices', () => {
 
       const product = schema.getType('Product') as GraphQLObjectType;
 
-      expect(product.federation.serviceName).toEqual('serviceB');
-      expect(product.getFields()['price'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product).serviceName).toEqual('serviceB');
+      expect(getFederationMetadata(product.getFields()['price']).serviceName).toEqual(
         'serviceA',
       );
     });
@@ -208,11 +209,11 @@ describe('composeServices', () => {
 
       const product = schema.getType('Product') as GraphQLObjectType;
 
-      expect(product.federation.serviceName).toEqual('serviceB');
-      expect(product.getFields()['price'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product).serviceName).toEqual('serviceB');
+      expect(getFederationMetadata(product.getFields()['price']).serviceName).toEqual(
         'serviceA',
       );
-      expect(product.getFields()['color'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product.getFields()['color']).serviceName).toEqual(
         'serviceC',
       );
     });
@@ -269,8 +270,8 @@ describe('composeServices', () => {
                         }
                   `);
 
-      expect(product.federation.serviceName).toEqual('serviceB');
-      expect(product.getFields()['price'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product).serviceName).toEqual('serviceB');
+      expect(getFederationMetadata(product.getFields()['price']).serviceName).toEqual(
         'serviceC',
       );
     });
@@ -353,10 +354,10 @@ describe('composeServices', () => {
                           name: String!
                         }
                   `);
-      expect(product.getFields()['sku'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product.getFields()['sku']).serviceName).toEqual(
         'serviceB',
       );
-      expect(product.getFields()['name'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product.getFields()['name']).serviceName).toEqual(
         'serviceB',
       );
     });
@@ -398,7 +399,7 @@ describe('composeServices', () => {
                                 name: String!
                               }
                         `);
-        expect(product.getFields()['name'].federation.serviceName).toEqual(
+        expect(getFederationMetadata(product.getFields()['name']).serviceName).toEqual(
           'serviceB',
         );
       });
@@ -445,7 +446,7 @@ describe('composeServices', () => {
                                 name: String!
                               }
                         `);
-        expect(product.getFields()['name'].federation.serviceName).toEqual(
+        expect(getFederationMetadata(product.getFields()['name']).serviceName).toEqual(
           'serviceB',
         );
       });
@@ -595,8 +596,8 @@ describe('composeServices', () => {
 
       const product = schema.getType('Product') as GraphQLObjectType;
 
-      expect(product.federation.serviceName).toEqual('serviceA');
-      expect(product.getFields()['id'].federation.serviceName).toEqual(
+      expect(getFederationMetadata(product).serviceName).toEqual('serviceA');
+      expect(getFederationMetadata(product.getFields()['id']).serviceName).toEqual(
         'serviceB',
       );
     });
@@ -635,7 +636,7 @@ describe('composeServices', () => {
 
       const query = schema.getQueryType();
 
-      expect(query.federation.serviceName).toBeUndefined();
+      expect(getFederationMetadata(query).serviceName).toBeUndefined();
     });
 
     it('treats root Query type definition as an extension, not base definitions', () => {
@@ -676,7 +677,7 @@ describe('composeServices', () => {
 
       const query = schema.getType('Query') as GraphQLObjectType;
 
-      expect(query.federation.serviceName).toBeUndefined();
+      expect(getFederationMetadata(query).serviceName).toBeUndefined();
     });
 
     it('allows extension of the Mutation type with no base type definition', () => {
@@ -806,7 +807,7 @@ describe('composeServices', () => {
 
         const product = schema.getType('Product');
 
-        expect(product.federation.externals).toMatchInlineSnapshot(`
+        expect(getFederationMetadata(product).externals).toMatchInlineSnapshot(`
                               Object {
                                 "serviceB--MISSING": Array [
                                   Object {
@@ -864,10 +865,10 @@ describe('composeServices', () => {
                                 price: Int!
                               }
                         `);
-        expect(product.getFields()['price'].federation.serviceName).toEqual(
+        expect(getFederationMetadata(product.getFields()['price']).serviceName).toEqual(
           'serviceB',
         );
-        expect(product.federation.serviceName).toEqual('serviceA');
+        expect(getFederationMetadata(product).serviceName).toEqual('serviceA');
       });
     });
 
@@ -897,7 +898,7 @@ describe('composeServices', () => {
 
         const product = schema.getType('Product') as GraphQLObjectType;
         expect(
-          product.getFields()['price'].federation.requires,
+          getFederationMetadata(product.getFields()['price']).requires,
         ).toMatchInlineSnapshot(`sku`);
       });
 
@@ -930,7 +931,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const product = schema.getType('Product') as GraphQLObjectType;
-        expect(product.getFields()['price'].federation.requires)
+        expect(getFederationMetadata(product.getFields()['price']).requires)
           .toMatchInlineSnapshot(`
                                 sku {
                                   id
@@ -970,7 +971,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const review = schema.getType('Review') as GraphQLObjectType;
-        expect(review.getFields()['product'].federation).toMatchInlineSnapshot(`
+        expect(getFederationMetadata(review.getFields()['product'])).toMatchInlineSnapshot(`
           Object {
             "belongsToValueType": false,
             "provides": sku,
@@ -1013,7 +1014,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const review = schema.getType('Review') as GraphQLObjectType;
-        expect(review.getFields()['product'].federation.provides)
+        expect(getFederationMetadata(review.getFields()['product']).provides)
           .toMatchInlineSnapshot(`
                                 sku {
                                   id
@@ -1050,7 +1051,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const review = schema.getType('Review') as GraphQLObjectType;
-        expect(review.getFields()['products'].federation)
+        expect(getFederationMetadata(review.getFields()['products']))
           .toMatchInlineSnapshot(`
           Object {
             "belongsToValueType": false,
@@ -1099,9 +1100,9 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const valueType = schema.getType('ValueType') as GraphQLObjectType;
-        const userField = valueType.getFields()['user'].federation;
-        expect(userField.belongsToValueType).toBe(true);
-        expect(userField.serviceName).toBe(null);
+        const userFieldFederationMetadata = getFederationMetadata(valueType.getFields()['user']);
+        expect(userFieldFederationMetadata.belongsToValueType).toBe(true);
+        expect(userFieldFederationMetadata.serviceName).toBe(null);
       });
     });
 
@@ -1131,7 +1132,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const product = schema.getType('Product') as GraphQLObjectType;
-        expect(product.federation.keys).toMatchInlineSnapshot(`
+        expect(getFederationMetadata(product).keys).toMatchInlineSnapshot(`
                               Object {
                                 "serviceA": Array [
                                   sku,
@@ -1172,7 +1173,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const product = schema.getType('Product') as GraphQLObjectType;
-        expect(product.federation.keys).toMatchInlineSnapshot(`
+        expect(getFederationMetadata(product).keys).toMatchInlineSnapshot(`
                               Object {
                                 "serviceA": Array [
                                   color {
@@ -1215,7 +1216,7 @@ describe('composeServices', () => {
         expect(errors).toHaveLength(0);
 
         const product = schema.getType('Product') as GraphQLObjectType;
-        expect(product.federation.keys).toMatchInlineSnapshot(`
+        expect(getFederationMetadata(product).keys).toMatchInlineSnapshot(`
                               Object {
                                 "serviceA": Array [
                                   color {

federation-js/src/composition/compose.ts

@@ -31,11 +31,15 @@ import {
   executableDirectiveLocations,
   stripTypeSystemDirectivesFromTypeDefs,
   defaultRootOperationNameLookup,
+  getFederationMetadata,
 } from './utils';
 import {
   ServiceDefinition,
   ExternalFieldDefinition,
   ServiceNameToKeyDirectivesMap,
+  FederationType,
+  FederationField,
+  FederationDirective,
 } from './types';
 import { validateSDL } from 'graphql/validation/validate';
 import { compositionRules } from './rules';
@@ -410,13 +414,18 @@ export function addFederationMetadataToSchemaNodes({
     const isValueType = valueTypes.has(typeName);
     const serviceName = isValueType ? null : owningService;
 
-    namedType.federation = {
-      ...namedType.federation,
+    const federationMetadata: FederationType = {
+      ...getFederationMetadata(namedType),
       serviceName,
       isValueType,
       ...(keyDirectivesMap[typeName] && {
         keys: keyDirectivesMap[typeName],
       }),
+    }
+
+    namedType.extensions = {
+      ...namedType.extensions,
+      federation: federationMetadata,
     };
 
     // For object types, add metadata for all the @provides directives from its fields
@@ -432,13 +441,18 @@ export function addFederationMetadataToSchemaNodes({
           providesDirective.arguments &&
           isStringValueNode(providesDirective.arguments[0].value)
         ) {
-          field.federation = {
-            ...field.federation,
+          const fieldFederationMetadata: FederationField = {
+            ...getFederationMetadata(field),
             serviceName,
             provides: parseSelections(
               providesDirective.arguments[0].value.value,
             ),
             belongsToValueType: isValueType,
+          }
+
+          field.extensions = {
+            ...field.extensions,
+            federation: fieldFederationMetadata
           };
         }
       }
@@ -455,9 +469,15 @@ export function addFederationMetadataToSchemaNodes({
       // TODO: Why don't we need to check for non-object types here
       if (isObjectType(namedType)) {
         const field = namedType.getFields()[fieldName];
-        field.federation = {
-          ...field.federation,
+
+        const fieldFederationMetadata: FederationField = {
+          ...getFederationMetadata(field),
           serviceName: extendingServiceName,
+        }
+
+        field.extensions = {
+          ...field.extensions,
+          federation: fieldFederationMetadata,
         };
 
         const [requiresDirective] = findDirectivesOnTypeOrField(
@@ -470,11 +490,16 @@ export function addFederationMetadataToSchemaNodes({
           requiresDirective.arguments &&
           isStringValueNode(requiresDirective.arguments[0].value)
         ) {
-          field.federation = {
-            ...field.federation,
+          const fieldFederationMetadata: FederationField = {
+            ...getFederationMetadata(field),
             requires: parseSelections(
               requiresDirective.arguments[0].value.value,
             ),
+          }
+
+          field.extensions = {
+            ...field.extensions,
+            federation: fieldFederationMetadata,
           };
         }
       }
@@ -485,31 +510,38 @@ export function addFederationMetadataToSchemaNodes({
     const namedType = schema.getType(field.parentTypeName);
     if (!namedType) continue;
 
-    namedType.federation = {
-      ...namedType.federation,
+    const existingMetadata = getFederationMetadata(namedType);
+    const typeFederationMetadata: FederationType = {
+      ...existingMetadata,
       externals: {
-        ...(namedType.federation && namedType.federation.externals),
+        ...existingMetadata?.externals,
         [field.serviceName]: [
-          ...(namedType.federation &&
-          namedType.federation.externals &&
-          namedType.federation.externals[field.serviceName]
-            ? namedType.federation.externals[field.serviceName]
-            : []),
+          ...(existingMetadata?.externals?.[field.serviceName] || []),
           field,
         ],
       },
     };
+
+    namedType.extensions = {
+      ...namedType.extensions,
+      federation: typeFederationMetadata,
+    };
   }
 
   // add all definitions of a specific directive for validation later
   for (const directiveName of Object.keys(directiveDefinitionsMap)) {
     const directive = schema.getDirective(directiveName);
     if (!directive) continue;
 
-    directive.federation = {
-      ...directive.federation,
+    const directiveFederationMetadata: FederationDirective = {
+      ...getFederationMetadata(directive),
       directiveDefinitions: directiveDefinitionsMap[directiveName],
-    };
+    }
+
+    directive.extensions = {
+      ...directive.extensions,
+      federation: directiveFederationMetadata,
+    }
   }
 }