feat(ferry_generator): external schema import

packages/ferry_generator/lib/graphql_builder.dart

@@ -46,7 +46,7 @@ class GraphqlBuilder implements Builder {
   @override
   FutureOr<void> build(BuildStep buildStep) async {
     SourceNode? schema;
-    AssetId? _schemaId;
+    late AssetId _schemaId;
     final doc = await readDocument(buildStep, config.sourceExtension);
     final docPackage = buildStep.inputId.package;
     final docDirPath = p.dirname(buildStep.inputId.path);
@@ -82,16 +82,20 @@ class GraphqlBuilder implements Builder {
     final triStateValueConfig = config.triStateOptionalsConfig;
 
     final schemaOutputAsset =
-        outputAssetId(_schemaId!, schemaExtension, config.outputDir);
+        outputAssetId(_schemaId, schemaExtension, config.outputDir);
 
     final schemaUrl = schemaOutputAsset.uri.toString();
+    final serializerOutputAsset =
+        AssetId(buildStep.inputId.package, schemaOutputAsset.path);
+    final serializerUrl = serializerOutputAsset.uri.toString();
     final schemaAllocator = GqlAllocator(
       buildStep.inputId.uri.toString(),
       config.sourceExtension,
       outputAssetId(buildStep.inputId, schemaExtension, config.outputDir)
           .uri
           .toString(),
       schemaUrl,
+      serializerUrl,
       config.outputDir,
     );
 
@@ -123,15 +127,15 @@ class GraphqlBuilder implements Builder {
         dataToVarsMode,
       ),
       schemaExtension: buildSchemaLibrary(
-          doc,
-          p.basename(generatedFilePath(buildStep.inputId, schemaExtension)),
-          config.typeOverrides,
-          config.enumFallbackConfig,
-          generatePossibleTypesMap: config.shouldGeneratePossibleTypes,
-          allocator: schemaAllocator,
-          triStateValueConfig: triStateValueConfig,
-          generateVarsCreateFactories:
-              config.shouldGenerateVarsCreateFactories),
+        doc,
+        p.basename(generatedFilePath(buildStep.inputId, schemaExtension)),
+        config.typeOverrides,
+        config.enumFallbackConfig,
+        generatePossibleTypesMap: config.shouldGeneratePossibleTypes,
+        allocator: schemaAllocator,
+        triStateValueConfig: triStateValueConfig,
+        generateVarsCreateFactories: config.shouldGenerateVarsCreateFactories,
+      ),
     };
 
     for (var entry in libs.entries) {
@@ -140,11 +144,15 @@ class GraphqlBuilder implements Builder {
       final schemaOutputAsset =
           outputAssetId(_schemaId, schemaExtension, config.outputDir);
 
+      final serialzerOutputAsset =
+          AssetId(buildStep.inputId.package, schemaOutputAsset.path);
+
       final allocator = GqlAllocator(
         buildStep.inputId.uri.toString(),
         config.sourceExtension,
         generatedAsset.uri.toString(),
         schemaOutputAsset.uri.toString(),
+        serialzerOutputAsset.uri.toString(),
         config.outputDir,
       );
 

packages/ferry_generator/lib/serializer_builder.dart

@@ -91,19 +91,6 @@ class SerializerBuilder implements Builder {
     final nonBuiltClasses =
         SplayTreeSet<ClassElement>((a, b) => a.name.compareTo(b.name));
 
-    final hasSerializer = (ClassElement c) => c.fields.any((field) =>
-        field.isStatic &&
-        field.name == 'serializer' &&
-        field.type.element?.name == 'Serializer' &&
-        field.type.element?.source?.uri.toString() ==
-            'package:built_value/serializer.dart');
-
-    final isBuiltValue = (ClassElement c) => c.allSupertypes.any((interface) =>
-        (interface.element.name == 'Built' ||
-            interface.element.name == 'EnumClass') &&
-        interface.element.source.uri.toString() ==
-            'package:built_value/built_value.dart');
-
     final excludeFileIds = <String, AssetId>{};
     for (final excludeGlob in excludeFiles) {
       await for (final fileAssetId in buildStep.findAssets(excludeGlob)) {
@@ -114,17 +101,9 @@ class SerializerBuilder implements Builder {
     await for (final input in buildStep.findAssets(generatedFiles)) {
       if (excludeFileIds.containsKey(input.path)) continue;
       final lib = await buildStep.resolver.libraryFor(input);
-      lib.units
-          .expand((cu) => cu.classes)
-          .where((c) => hasSerializer(c) && isBuiltValue(c))
-          .forEach(builtClasses.add);
-
-      lib.units
-          .expand((cu) => cu.classes)
-          .where(
-            (c) => hasSerializer(c) && !isBuiltValue(c),
-          )
-          .forEach(nonBuiltClasses.add);
+      final classes = extractClassesToGenerateSerializersFor(lib);
+      builtClasses.addAll(classes.builtClasses);
+      nonBuiltClasses.addAll(classes.nonBuiltClasses);
     }
 
     final additionalSerializers = <Expression>{
@@ -141,26 +120,107 @@ class SerializerBuilder implements Builder {
       ),
     };
 
+    // if the schema is defined in a different package
+    // we need to import the serializers from that package
+    // and add them to the serializers of this package
+    final isExternalSchema = schemaId.package != buildStep.inputId.package;
+
+    final externalSerializersExpression = isExternalSchema
+        ? refer('serializers',
+                _externalSchemaSerializersImport(schemaId, config))
+            .property('serializers')
+        : null;
+
+    if (isExternalSchema) {
+      final externalSchemaId =
+          outputAssetId(schemaId, schemaExtension, config.outputDir);
+
+      final externalSchemaLibrary =
+          await buildStep.resolver.libraryFor(externalSchemaId);
+
+      final externalSchemaClasses =
+          extractClassesToGenerateSerializersFor(externalSchemaLibrary);
+
+      builtClasses.addAll(externalSchemaClasses.builtClasses);
+      nonBuiltClasses.addAll(externalSchemaClasses.nonBuiltClasses);
+    }
+
     final library = buildSerializerLibrary(
       builtClasses,
       outputFileName.replaceFirst('.gql.dart', '.gql.g.dart'),
       additionalSerializers,
+      externalSerializers: externalSerializersExpression,
     );
 
-    final allocator = PickAllocator(
-      doNotPick: ['package:built_value/serializer.dart'],
-      include: [
-        'package:built_collection/built_collection.dart',
-        'package:ferry_exec/ferry_exec.dart',
-        ...config.typeOverrides.values.map((ref) => ref.url).whereType<String>()
-      ],
-    );
+    final allocator = PickAllocator(doNotPick: [
+      'package:built_value/serializer.dart',
+    ], include: [
+      'package:built_collection/built_collection.dart',
+      'package:ferry_exec/ferry_exec.dart',
+      ...config.typeOverrides.values.map((ref) => ref.url).whereType<String>(),
+    ], aliasedImports: {
+      if (isExternalSchema)
+        _externalSchemaSerializersImport(schemaId, config):
+            '_\$external_serializers',
+    });
 
     final outputId = AssetId(
-      schemaId.package,
+      buildStep.inputId.package,
       p.joinAll(pathSegments(schemaId)),
     );
 
     await writeDocument(outputId, library, allocator, buildStep);
   }
 }
+
+String _externalSchemaSerializersImport(
+    AssetId schemaId, BuilderConfig config) {
+  final outPutId = outputAssetId(schemaId, schemaExtension, config.outputDir);
+
+  final serializersPathSegments = outPutId.pathSegments
+    ..removeAt(0)
+    ..removeLast()
+    ..add('serializers.gql.dart');
+
+  final outPutPath = p.joinAll(serializersPathSegments);
+
+  return 'package:${outPutId.package}/$outPutPath';
+}
+
+bool hasSerializer(ClassElement c) => c.fields.any((field) =>
+    field.isStatic &&
+    field.name == 'serializer' &&
+    field.type.element?.name == 'Serializer' &&
+    field.type.element?.source?.uri.toString() ==
+        'package:built_value/serializer.dart');
+
+bool isBuiltValue(ClassElement c) => c.allSupertypes.any((interface) =>
+    (interface.element.name == 'Built' ||
+        interface.element.name == 'EnumClass') &&
+    interface.element.source.uri.toString() ==
+        'package:built_value/built_value.dart');
+
+typedef ClassesToGenerateSerializersFor = ({
+  Set<ClassElement> builtClasses,
+  Set<ClassElement> nonBuiltClasses
+});
+
+ClassesToGenerateSerializersFor extractClassesToGenerateSerializersFor(
+    LibraryElement externalSchemaLibrary) {
+  final builtClasses = externalSchemaLibrary.units
+      .expand((cu) => cu.classes)
+      .where((c) => hasSerializer(c) && isBuiltValue(c))
+      .toSet();
+
+  final nonBuiltClasses = externalSchemaLibrary.units
+      .expand((cu) => cu.classes)
+      .where(
+        (c) => hasSerializer(c) && !isBuiltValue(c),
+      )
+      .toSet();
+
+  return (
+    builtClasses: builtClasses,
+    nonBuiltClasses: nonBuiltClasses,
+  );
+}

packages/ferry_generator/lib/src/allocators/gql_allocator.dart

@@ -19,6 +19,7 @@ class GqlAllocator implements Allocator {
   final String sourceExtension;
   final String currentUrl;
   final String schemaUrl;
+  final String serializerUrl;
   final String outputDir;
 
   final _imports = <String, int?>{};
@@ -29,6 +30,7 @@ class GqlAllocator implements Allocator {
     this.sourceExtension,
     this.currentUrl,
     this.schemaUrl,
+    this.serializerUrl,
     this.outputDir,
   );
 
@@ -69,7 +71,7 @@ class GqlAllocator implements Allocator {
       if (uri.fragment == 'schema') {
         replacedUrl = schemaUrl;
       } else if (uri.fragment == 'serializer') {
-        replacedUrl = '${p.dirname(schemaUrl)}/serializers.gql.dart';
+        replacedUrl = '${p.dirname(serializerUrl)}/serializers.gql.dart';
       } else {
         replacedUrl = outputPath(sourceUrl, outputDir).replaceAll(
           RegExp(r'.graphql$'),

packages/ferry_generator/lib/src/allocators/pick_allocator.dart

@@ -4,12 +4,14 @@ import 'package:code_builder/code_builder.dart';
 class PickAllocator implements Allocator {
   final List<String> doNotPick;
   final List<String> include;
+  final Map<String, String> aliasedImports;
 
   final Map<String, List<String>?> _imports = {};
 
   PickAllocator({
     this.doNotPick = const [],
     this.include = const [],
+    this.aliasedImports = const {},
   }) {
     for (final url in include) {
       _imports[url] = null;
@@ -30,6 +32,9 @@ class PickAllocator implements Allocator {
     } else if (doNotPick.contains(url) || include.contains(url)) {
       _imports.putIfAbsent(url, () => null);
       return symbol;
+    } else if (aliasedImports.containsKey(url)) {
+      final alias = aliasedImports[url]!;
+      return '$alias.$symbol';
     }
 
     _imports.update(url, (symbols) => symbols?..add(symbol),
@@ -39,9 +44,13 @@ class PickAllocator implements Allocator {
   }
 
   @override
-  Iterable<Directive> get imports => _imports.entries.map(
+  Iterable<Directive> get imports => _imports.entries
+      .map(
         (u) => u.value == null
             ? Directive.import(u.key)
             : Directive.import(u.key, show: u.value!),
-      );
+      )
+      .followedBy(aliasedImports.entries.map(
+        (e) => Directive.import(e.key, as: e.value),
+      ));
 }

packages/ferry_generator/pubspec.yaml

@@ -12,7 +12,7 @@ topics:
   - codegen
 dependencies:
   gql: '>=0.14.0 <2.0.0'
-  gql_code_builder: ^0.12.0
+  gql_code_builder: ^0.13.0
   gql_code_builder_serializers: ^0.1.0
   gql_tristate_value: ^1.0.0
   built_collection: ^5.0.0

packages/ferry_test_external_schema/.gitignore

@@ -0,0 +1,4 @@
+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+pubspec.lock

packages/ferry_test_external_schema/CHANGELOG.md

@@ -0,0 +1,3 @@
+## 1.0.0
+
+- Initial version.

packages/ferry_test_external_schema/analysis_options.yaml

@@ -0,0 +1 @@
+include: package:pedantic/analysis_options.yaml

packages/ferry_test_external_schema/build.yaml

@@ -0,0 +1,24 @@
+targets:
+  $default:
+    builders:
+      ferry_generator|graphql_builder:
+        enabled: true
+        options:
+          schema: ferry_test_graphql2|lib/schema/schema.graphql
+          tristate_optionals: false
+          vars_create_factories: false
+          data_to_json: type_safe
+          type_overrides:
+            Date:
+              name: DateTime
+
+      ferry_generator|serializer_builder:
+        enabled: true
+        options:
+          schema: ferry_test_graphql2|lib/schema/schema.graphql
+          type_overrides:
+            Date:
+              name: DateTime
+          custom_serializers:
+            - import: 'package:ferry_test_graphql2/date_serializer.dart'
+              name: DateSerializer