feat: check if is trying to use fed2 without apollo subgraph 2

Author: greguintow

packages/graphql/lib/federation/graphql-federation.factory.ts

@@ -1,6 +1,6 @@
 import { mergeSchemas } from '@graphql-tools/schema';
 import { printSchemaWithDirectives } from '@graphql-tools/utils';
-import { Injectable } from '@nestjs/common';
+import { Injectable, Logger } from '@nestjs/common';
 import { loadPackage } from '@nestjs/common/utils/load-package.util';
 import { isString } from '@nestjs/common/utils/shared.utils';
 import {
@@ -98,7 +98,7 @@ export class GraphQLFederationFactory {
       await import('@apollo/subgraph/package.json')
     ).version;
 
-    const isaApolloSubgraph2 = Number(apolloSubgraphVersion.split('.')[0]) >= 2;
+    const isApolloSubgraph2 = Number(apolloSubgraphVersion.split('.')[0]) >= 2;
     const printSubgraphSchema = apolloSubgraph.printSubgraphSchema;
 
     if (!buildFederatedSchema) {
@@ -110,10 +110,10 @@ export class GraphQLFederationFactory {
       options,
       this.resolversExplorerService.getAllCtors(),
     );
-    let typeDefs = isaApolloSubgraph2
+    let typeDefs = isApolloSubgraph2
       ? printSchemaWithDirectives(autoGeneratedSchema)
       : printSubgraphSchema(autoGeneratedSchema);
-    if (options.useFed2) {
+    if (options.useFed2 && isApolloSubgraph2) {
       const {
         directives = [
           '@key',
@@ -138,6 +138,11 @@ export class GraphQLFederationFactory {
         extend schema @link(url: "${url}", import: [${mappedDirectives}])
         ${typeDefs}
       `;
+    } else if (options.useFed2 && !isApolloSubgraph2) {
+      Logger.error(
+        'You are trying to use Apollo Federation 2 but you are not using @apollo/subgraph@^2.0.0, please upgrade',
+        'GraphQLFederationFactory',
+      );
     }
 
     let executableSchema: GraphQLSchema = buildFederatedSchema({