Stitching Directives (#2227)

Release alpha version of stitching directives that allows directive annotated subschemas, so that merge configuration can be more automated.

Author: yaacovCR

.changeset/old-apples-remain.md

@@ -0,0 +1,8 @@
+---
+'@graphql-tools/stitching-directives': patch
+'@graphql-tools/schema': patch
+'@graphql-tools/stitch': patch
+'@graphql-tools/utils': patch
+---
+
+add ability to specify merge config within subschemas using directives

packages/schema/src/types.ts

@@ -77,4 +77,4 @@ export interface IExecutableSchemaDefinition<TContext = any> {
   noExtensionExtraction?: boolean;
 }
 
-export type ExecutableSchemaTransformation = (originalWrappingSchema: GraphQLSchema) => GraphQLSchema;
+export type ExecutableSchemaTransformation = (schema: GraphQLSchema) => GraphQLSchema;

packages/stitch/src/isolateComputedFields.ts

@@ -59,14 +59,15 @@ function filterBaseSubschema(
   subschemaConfig: SubschemaConfig,
   isolatedSchemaTypes: Record<string, MergedTypeConfig>
 ): SubschemaConfig {
+  const schema = subschemaConfig.schema;
   const typesForInterface: Record<string, string[]> = {};
   const filteredSchema = pruneSchema(
     filterSchema({
-      schema: subschemaConfig.schema,
+      schema,
       objectFieldFilter: (typeName, fieldName) => !isolatedSchemaTypes[typeName]?.fields[fieldName],
       interfaceFieldFilter: (typeName, fieldName) => {
         if (!typesForInterface[typeName]) {
-          typesForInterface[typeName] = getImplementingTypes(typeName, subschemaConfig.schema);
+          typesForInterface[typeName] = getImplementingTypes(typeName, schema);
         }
         return !typesForInterface[typeName].some(
           implementingTypeName => isolatedSchemaTypes[implementingTypeName]?.fields[fieldName]