[Federation] Allow specified directives during validation (apollograp…

…hql/apollo-server#2823)

The keyFieldsMissingExternal validator should permit standard
directives just like we do in composition everywhere else.
Apollo-Orig-Commit-AS: apollographql/apollo-server@4415648

federation-js/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### vNEXT
 
+* Allow specified directives during validation (@deprecated) [#2823](https://github.com/apollographql/apollo-server/pull/2823)
+
 # v0.6.1
 
 * Normalize SDL in a normalization step before validation [#2771](https://github.com/apollographql/apollo-server/pull/2771)

federation-js/src/composition/validate/preComposition/__tests__/keyFieldsMissingExternal.test.ts

@@ -51,6 +51,37 @@ describe('keyFieldsMissingExternal', () => {
     expect(warnings).toHaveLength(0);
   });
 
+  it('has no warnings with @deprecated directive usage', () => {
+    const serviceA = {
+      typeDefs: gql`
+        extend type Car @key(fields: "model { name kit { upc } } year") {
+          model: Model! @external
+          year: String! @external
+          color: String! @deprecated(reason: "Use colors instead")
+          colors: Color!
+        }
+
+        extend type Model {
+          name: String! @external
+          kit: Kit @external
+        }
+
+        extend type Kit {
+          upc: String! @external
+        }
+
+        enum Color {
+          Red
+          Blue
+        }
+      `,
+      name: 'serviceA',
+    };
+
+    const warnings = validateKeyFieldsMissingExternal(serviceA);
+    expect(warnings).toHaveLength(0);
+  });
+
   it("warns when a @key argument doesn't reference an @external field", () => {
     const serviceA = {
       typeDefs: gql`

federation-js/src/composition/validate/preComposition/keyFieldsMissingExternal.ts

@@ -5,6 +5,7 @@ import {
   parse,
   GraphQLSchema,
   GraphQLError,
+  specifiedDirectives,
 } from 'graphql';
 import { buildSchemaFromSDL } from 'apollo-graphql';
 import { isNotNullOrUndefined } from 'apollo-env';
@@ -58,7 +59,7 @@ export const keyFieldsMissingExternal = ({
   // this allows us to build a partial schema
   let schema = new GraphQLSchema({
     query: undefined,
-    directives: federationDirectives,
+    directives: [...specifiedDirectives, ...federationDirectives],
   });
   try {
     schema = buildSchemaFromSDL(typeDefs, schema);