fix(delegate): handle variables correctly (#3320)

* fix(delegate): handle variables correctly

* More readable visitor key maps

* Handle variables on directives as well

.changeset/serious-apes-check.md

@@ -0,0 +1,5 @@
+---
+'@graphql-tools/delegate': patch
+---
+
+fix(delegate): handle variables correctly

packages/delegate/src/finalizeGatewayRequest.ts

@@ -1,5 +1,6 @@
 import {
   ArgumentNode,
+  ASTKindToNode,
   FragmentDefinitionNode,
   getNamedType,
   GraphQLField,
@@ -16,6 +17,7 @@ import {
   TypeNameMetaFieldDef,
   VariableDefinitionNode,
   visit,
+  VisitorKeyMap,
   visitWithTypeInfo,
 } from 'graphql';
 
@@ -280,6 +282,26 @@ function collectFragmentVariables(
   };
 }
 
+const filteredSelectionSetVisitorKeys: Partial<VisitorKeyMap<ASTKindToNode>> = {
+  SelectionSet: ['selections'],
+  Field: ['selectionSet'],
+  InlineFragment: ['selectionSet'],
+  FragmentDefinition: ['selectionSet'],
+};
+
+const variablesVisitorKeys: Partial<VisitorKeyMap<ASTKindToNode>> = {
+  SelectionSet: ['selections'],
+  Field: ['arguments', 'directives', 'selectionSet'],
+  Argument: ['value'],
+
+  InlineFragment: ['directives', 'selectionSet'],
+  FragmentDefinition: ['directives', 'selectionSet'],
+
+  ObjectValue: ['fields'],
+  ObjectField: ['name', 'value'],
+  Directive: ['arguments'],
+};
+
 function finalizeSelectionSet(
   schema: GraphQLSchema,
   type: GraphQLType,
@@ -390,61 +412,7 @@ function finalizeSelectionSet(
     // visitorKeys argument usage a la https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-source-graphql/src/batching/merge-queries.js
     // empty keys cannot be removed only because of typescript errors
     // will hopefully be fixed in future version of graphql-js to be optional
-    {
-      Name: [],
-
-      Document: [],
-      OperationDefinition: [],
-      VariableDefinition: [],
-      Variable: [],
-      SelectionSet: ['selections'],
-      Field: ['selectionSet'],
-      Argument: [],
-
-      FragmentSpread: [],
-      InlineFragment: ['selectionSet'],
-      FragmentDefinition: ['selectionSet'],
-
-      IntValue: [],
-      FloatValue: [],
-      StringValue: [],
-      BooleanValue: [],
-      NullValue: [],
-      EnumValue: [],
-      ListValue: [],
-      ObjectValue: [],
-      ObjectField: [],
-
-      Directive: [],
-
-      NamedType: [],
-      ListType: [],
-      NonNullType: [],
-
-      SchemaDefinition: [],
-      OperationTypeDefinition: [],
-
-      ScalarTypeDefinition: [],
-      ObjectTypeDefinition: [],
-      FieldDefinition: [],
-      InputValueDefinition: [],
-      InterfaceTypeDefinition: [],
-      UnionTypeDefinition: [],
-      EnumTypeDefinition: [],
-      EnumValueDefinition: [],
-      InputObjectTypeDefinition: [],
-
-      DirectiveDefinition: [],
-
-      SchemaExtension: [],
-
-      ScalarTypeExtension: [],
-      ObjectTypeExtension: [],
-      InterfaceTypeExtension: [],
-      UnionTypeExtension: [],
-      EnumTypeExtension: [],
-      InputObjectTypeExtension: [],
-    }
+    filteredSelectionSetVisitorKeys as any
   );
 
   visit(
@@ -457,61 +425,7 @@ function finalizeSelectionSet(
     // visitorKeys argument usage a la https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-source-graphql/src/batching/merge-queries.js
     // empty keys cannot be removed only because of typescript errors
     // will hopefully be fixed in future version of graphql-js to be optional
-    {
-      Name: [],
-
-      Document: [],
-      OperationDefinition: [],
-      VariableDefinition: [],
-      Variable: [],
-      SelectionSet: ['selections'],
-      Field: ['arguments', 'selectionSet'],
-      Argument: ['value'],
-
-      FragmentSpread: [],
-      InlineFragment: ['selectionSet'],
-      FragmentDefinition: ['selectionSet'],
-
-      IntValue: [],
-      FloatValue: [],
-      StringValue: [],
-      BooleanValue: [],
-      NullValue: [],
-      EnumValue: [],
-      ListValue: [],
-      ObjectValue: [],
-      ObjectField: [],
-
-      Directive: [],
-
-      NamedType: [],
-      ListType: [],
-      NonNullType: [],
-
-      SchemaDefinition: [],
-      OperationTypeDefinition: [],
-
-      ScalarTypeDefinition: [],
-      ObjectTypeDefinition: [],
-      FieldDefinition: [],
-      InputValueDefinition: [],
-      InterfaceTypeDefinition: [],
-      UnionTypeDefinition: [],
-      EnumTypeDefinition: [],
-      EnumValueDefinition: [],
-      InputObjectTypeDefinition: [],
-
-      DirectiveDefinition: [],
-
-      SchemaExtension: [],
-
-      ScalarTypeExtension: [],
-      ObjectTypeExtension: [],
-      InterfaceTypeExtension: [],
-      UnionTypeExtension: [],
-      EnumTypeExtension: [],
-      InputObjectTypeExtension: [],
-    }
+    variablesVisitorKeys as any
   );
 
   return {

packages/delegate/tests/delegateToSchema.test.ts

@@ -2,8 +2,10 @@ import { graphql } from 'graphql';
 
 import { delegateToSchema } from '../src/delegateToSchema';
 import { makeExecutableSchema } from '@graphql-tools/schema';
+import { wrapSchema } from '@graphql-tools/wrap';
+import { stitchSchemas } from '@graphql-tools/stitch';
 
-function assertSome<T>(input: T): asserts input is Exclude<T, null | undefined>{
+function assertSome<T>(input: T): asserts input is Exclude<T, null | undefined> {
   if (input == null) {
     throw new Error("Value should be neither null nor undefined.")
   }
@@ -155,4 +157,84 @@ describe('delegateToSchema', () => {
     assertSome(result.data)
     expect(result.data['delegateToSchema']).toEqual('test');
   });
+  test('should work even when there are variables for nested fields', async () => {
+    const innerSchema = makeExecutableSchema({
+      typeDefs: `
+        input TestInput {
+          strings: [String]
+        }
+        type Test {
+          strings: [String]
+        }
+        type Query {
+          test(input: TestInput): Test
+        }
+      `,
+      resolvers: {
+        Query: {
+          test: (_root, args) => args.input
+        },
+      },
+    });
+
+    const outerSchema = wrapSchema({ schema: innerSchema });
+
+    const result = await graphql({
+      schema: outerSchema,
+      source: /* GraphQL */ `
+        query test($strings: [String]) {
+          test(input: { strings: $strings }) {
+            strings
+          }
+        }
+      `,
+      variableValues: {
+        strings: ['foo', 'bar']
+      }
+    });
+
+    assertSome(result.data);
+    expect(result.data).toEqual({
+      test: {
+        strings: ['foo', 'bar']
+      }
+    });
+  });
+  test('should work variables in directives', async () => {
+    const sourceSchema = makeExecutableSchema({
+      typeDefs: /* GraphQL */`
+                type Query {
+                  users(input: UsersInput!): [User!]!
+                }
+
+                type User {
+                  name: String!
+                  age: Int!
+                }
+
+                input UsersInput {
+                  limit: Int
+                }
+      `,
+      resolvers: {
+        Query: {
+          users: () => {
+            return [
+              { name: 'ABC', age: 10 },
+              { name: 'DEF', age: 20 },
+            ];
+          },
+        },
+      },
+    });
+    const stitchedSchema = stitchSchemas({ subschemas: [sourceSchema] });
+
+    const result = await graphql({
+      schema: stitchedSchema,
+      source: /* GraphQL */`query($input: UsersInput!, $skip_age: Boolean!) { users(input: $input) { name age @skip (if: $skip_age) } }`,
+      variableValues: { input: { limit: 5 }, skip_age: true },
+    });
+
+    expect(result).toEqual({ "data": { "users": [{ "name": "ABC" }, { "name": "DEF" }] } });
+  })
 });