Remove standard directives from SDL output

graphql-java-support/src/main/java/com/apollographql/federation/graphqljava/SchemaTransformer.java

@@ -16,12 +16,17 @@
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 
 public final class SchemaTransformer {
     private static final Object DUMMY = new Object();
+    // Apollo Gateway will fail composition if it sees directive definitions for these
+    private static final Set<String> HIDDEN_DIRECTIVES =
+            new HashSet<>(Arrays.asList("deprecated", "include", "skip"));
     private final GraphQLSchema originalSchema;
     private TypeResolver entityTypeResolver = null;
     private DataFetcher entitiesDataFetcher = null;
@@ -143,7 +148,9 @@ private String sdl() {
                 .includeScalarTypes(true)
                 .includeExtendedScalarTypes(true)
                 .includeSchemaDefinition(true)
-                .includeDirectives(true);
+                // Note that includeDirectives() will filter directive definitions and usages, with
+                // the exception of directive usages of @deprecated (which are never removed).
+                .includeDirectives(directive -> !HIDDEN_DIRECTIVES.contains(directive.getName()));
         return new FederationSdlPrinter(options).print(originalSchema);
     }
 }

graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/FederationTest.java

@@ -42,7 +42,7 @@ void testEmpty() {
                 "\n" +
                 "type _Service {\n" +
                 "  sdl: String!\n" +
-                "}\n", SchemaUtils.printSchema(federated));
+                "}\n", SchemaUtils.printWithoutStandardDirectiveDefinitions(federated));
 
         final GraphQLType _Service = federated.getType("_Service");
         assertNotNull(_Service, "_Service type present");
@@ -148,6 +148,9 @@ void testPrinter() {
                 typeDefinitionRegistry,
                 runtimeWiring
         );
-        Assertions.assertEquals(printerSDL.trim(), new FederationSdlPrinter().print(graphQLSchema).trim());
+        Assertions.assertEquals(
+                printerSDL.trim(),
+                SchemaUtils.printWithoutStandardDirectiveDefinitions(graphQLSchema).trim()
+        );
     }
 }

graphql-java-support/src/test/java/com/apollographql/federation/graphqljava/SchemaUtils.java

@@ -3,20 +3,27 @@
 import graphql.ExecutionResult;
 import graphql.schema.GraphQLSchema;
 
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 
 import static graphql.ExecutionInput.newExecutionInput;
 import static graphql.GraphQL.newGraphQL;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 final class SchemaUtils {
+    static final Set<String> standardDirectives =
+            new HashSet<>(Arrays.asList("deprecated", "include", "skip"));
 
     private SchemaUtils() {
     }
 
-    static String printSchema(GraphQLSchema schema) {
-        return new FederationSdlPrinter().print(schema);
+    static String printWithoutStandardDirectiveDefinitions(GraphQLSchema schema) {
+        return new FederationSdlPrinter(FederationSdlPrinter.Options.defaultOptions()
+                .includeDirectives(directive -> !standardDirectives.contains(directive.getName()))
+        ).print(schema);
     }
 
     static ExecutionResult execute(GraphQLSchema schema, String query) {