[gql_code_builder] optimize slow code generation to reduce build time as 10% of previous.

codegen/gql_build/lib/gql_build.dart

@@ -19,12 +19,14 @@ Builder dataBuilder(
   BuilderOptions options,
 ) =>
     DataBuilder(
-        AssetId.parse(
-          options.config["schema"] as String,
-        ),
-        (options.config["add_typenames"] ?? true) as bool,
-        typeOverrideMap(options.config["type_overrides"]),
-        whenExtensionConfig: whenExtensionConfig(options.config));
+      AssetId.parse(
+        options.config["schema"] as String,
+      ),
+      (options.config["add_typenames"] ?? true) as bool,
+      typeOverrideMap(options.config["type_overrides"]),
+      whenExtensionConfig: whenExtensionConfig(options.config),
+      dataClassConfig: dataClassConfig(options.config),
+    );
 
 /// Builds GraphQL type-safe request builder
 Builder reqBuilder(

codegen/gql_build/lib/src/data_builder.dart

@@ -14,6 +14,7 @@ class DataBuilder implements Builder {
   final bool addTypenames;
   final Map<String, Reference> typeOverrides;
   final InlineFragmentSpreadWhenExtensionConfig whenExtensionConfig;
+  final DataClassConfig dataClassConfig;
 
   DataBuilder(
     this.schemaId,
@@ -23,6 +24,9 @@ class DataBuilder implements Builder {
       generateWhenExtensionMethod: false,
       generateMaybeWhenExtensionMethod: false,
     ),
+    this.dataClassConfig = const DataClassConfig(
+      reuseFragments: false,
+    ),
   });
 
   @override
@@ -41,11 +45,13 @@ class DataBuilder implements Builder {
         .path;
 
     final library = buildDataLibrary(
-        addTypenames ? introspection.addTypenames(doc) : doc,
-        introspection.addTypenames(schema),
-        basename(generatedPartUrl),
-        typeOverrides,
-        whenExtensionConfig);
+      addTypenames ? introspection.addTypenames(doc) : doc,
+      introspection.addTypenames(schema),
+      basename(generatedPartUrl),
+      typeOverrides,
+      whenExtensionConfig,
+      dataClassConfig,
+    );
 
     return writeDocument(
       library,

codegen/gql_build/lib/src/utils/config.dart

@@ -42,6 +42,10 @@ EnumFallbackConfig enumFallbackConfig(Map<String, dynamic> config) =>
       fallbackValueMap: enumFallbackMap(config["enum_fallbacks"]),
     );
 
+DataClassConfig dataClassConfig(Map<String, dynamic> config) => DataClassConfig(
+      reuseFragments: config["reuse_fragments"] == true,
+    );
+
 InlineFragmentSpreadWhenExtensionConfig whenExtensionConfig(
     Map<String, dynamic> config) {
   final whenYamlConfig = config["when_extensions"] as YamlMap?;

codegen/gql_code_builder/lib/data.dart

@@ -1,11 +1,14 @@
 import "package:built_collection/built_collection.dart";
 import "package:code_builder/code_builder.dart";
 import "package:gql/ast.dart";
+import "package:gql_code_builder/src/common.dart";
+import "package:gql_code_builder/src/config/data_class_config.dart";
 import "package:gql_code_builder/src/config/when_extension_config.dart";
 
 import "./source.dart";
 import "./src/operation/data.dart";
 
+export "package:gql_code_builder/src/config/data_class_config.dart";
 export "package:gql_code_builder/src/config/when_extension_config.dart";
 
 Library buildDataLibrary(
@@ -18,7 +21,15 @@ Library buildDataLibrary(
     generateWhenExtensionMethod: false,
     generateMaybeWhenExtensionMethod: false,
   ),
+  DataClassConfig dataClassConfig = const DataClassConfig(
+    reuseFragments: false,
+  ),
 ]) {
+  final fragmentMap = _fragmentMap(docSource);
+  final dataClassAliasMap = dataClassConfig.reuseFragments
+      ? _dataClassAliasMap(docSource, fragmentMap)
+      : <String, Reference>{};
+
   final operationDataClasses = docSource.document.definitions
       .whereType<OperationDefinitionNode>()
       .expand(
@@ -28,6 +39,8 @@ Library buildDataLibrary(
           schemaSource,
           typeOverrides,
           whenExtensionConfig,
+          fragmentMap,
+          dataClassAliasMap,
         ),
       )
       .toList();
@@ -41,6 +54,8 @@ Library buildDataLibrary(
           schemaSource,
           typeOverrides,
           whenExtensionConfig,
+          fragmentMap,
+          dataClassAliasMap,
         ),
       )
       .toList();
@@ -54,3 +69,140 @@ Library buildDataLibrary(
       ]),
   );
 }
+
+Map<String, SourceSelections> _fragmentMap(SourceNode source) => {
+      for (var def
+          in source.document.definitions.whereType<FragmentDefinitionNode>())
+        def.name.value: SourceSelections(
+          url: source.url,
+          selections: def.selectionSet.selections,
+        ),
+      for (var import in source.imports) ..._fragmentMap(import)
+    };
+
+Map<String, Reference> _dataClassAliasMap(
+    SourceNode source, Map<String, SourceSelections> fragmentMap,
+    [Map<String, Reference>? aliasMap, Set<String>? visitedSource]) {
+  aliasMap ??= {};
+  visitedSource ??= {};
+
+  source.imports.forEach((s) {
+    if (!visitedSource!.contains(source.url)) {
+      visitedSource.add(source.url);
+      _dataClassAliasMap(s, fragmentMap, aliasMap);
+    }
+  });
+
+  for (final def
+      in source.document.definitions.whereType<OperationDefinitionNode>()) {
+    _dataClassAliasMapDFS(
+      typeRefPrefix: builtClassName("${def.name!.value}Data"),
+      getAliasTypeName: (fragmentName) => "${builtClassName(fragmentName)}Data",
+      selections: def.selectionSet.selections,
+      fragmentMap: fragmentMap,
+      aliasMap: aliasMap,
+    );
+  }
+
+  for (final def
+      in source.document.definitions.whereType<FragmentDefinitionNode>()) {
+    _dataClassAliasMapDFS(
+      typeRefPrefix: builtClassName(def.name.value),
+      getAliasTypeName: builtClassName,
+      selections: def.selectionSet.selections,
+      fragmentMap: fragmentMap,
+      aliasMap: aliasMap,
+    );
+    _dataClassAliasMapDFS(
+      typeRefPrefix: builtClassName("${def.name.value}Data"),
+      getAliasTypeName: (fragmentName) => "${builtClassName(fragmentName)}Data",
+      selections: def.selectionSet.selections,
+      fragmentMap: fragmentMap,
+      aliasMap: aliasMap,
+    );
+  }
+
+  return aliasMap;
+}
+
+void _dataClassAliasMapDFS({
+  required String typeRefPrefix,
+  required String Function(String fragmentName) getAliasTypeName,
+  required List<SelectionNode> selections,
+  required Map<String, SourceSelections> fragmentMap,
+  required Map<String, Reference> aliasMap,
+}) {
+  if (selections.isEmpty) return;
+
+  // flatten selections to extract untouched fragments while visiting children.
+  final shrunkenSelections =
+      shrinkSelections(mergeSelections(selections, fragmentMap), fragmentMap);
+
+  // alias single fragment and finish
+  final selectionsWithoutTypename = shrunkenSelections
+      .where((s) => !(s is FieldNode && s.name.value == "__typename"));
+  if (selectionsWithoutTypename.length == 1 &&
+      selectionsWithoutTypename.first is FragmentSpreadNode) {
+    final node = selectionsWithoutTypename.first as FragmentSpreadNode;
+    final fragment = fragmentMap[node.name.value];
+    final fragmentTypeName = getAliasTypeName(node.name.value);
+    aliasMap[typeRefPrefix] =
+        refer(fragmentTypeName, "${fragment!.url ?? ""}#data");
+    // print("alias $typeRefPrefix => $fragmentTypeName");
+    return;
+  }
+
+  for (final node in selectionsWithoutTypename) {
+    if (node is FragmentSpreadNode) {
+      // exclude redefined selections from each fragment selections
+      final fragmentSelections = fragmentMap[node.name.value]!.selections;
+      final exclusiveFragmentSelections =
+          mergeSelections(fragmentSelections, fragmentMap).where((s1) {
+        if (s1 is FieldNode) {
+          final name = (s1.alias ?? s1.name).value;
+          return selectionsWithoutTypename
+              .whereType<FieldNode>()
+              .every((s2) => name != (s2.alias ?? s2.name).value);
+        } else if (s1 is InlineFragmentNode && s1.typeCondition != null) {
+          /// TODO: Handle inline fragments without a type condition
+          final name = s1.typeCondition!.on.name.value;
+          return selectionsWithoutTypename
+              .whereType<InlineFragmentNode>()
+              .every((s2) => name != s2.typeCondition?.on.name.value);
+        }
+        return false;
+      }).toList();
+
+      _dataClassAliasMapDFS(
+        typeRefPrefix: typeRefPrefix,
+        getAliasTypeName: getAliasTypeName,
+        selections: exclusiveFragmentSelections,
+        fragmentMap: fragmentMap,
+        aliasMap: aliasMap,
+      );
+    } else if (node is InlineFragmentNode) {
+      if (node.typeCondition != null) {
+        /// TODO: Handle inline fragments without a type condition
+        _dataClassAliasMapDFS(
+          typeRefPrefix:
+              "${typeRefPrefix}__as${node.typeCondition!.on.name.value}",
+          getAliasTypeName: getAliasTypeName,
+          selections: [
+            ...selections.where((s) => s != node),
+            ...node.selectionSet.selections,
+          ],
+          fragmentMap: fragmentMap,
+          aliasMap: aliasMap,
+        );
+      }
+    } else if (node is FieldNode && node.selectionSet != null) {
+      _dataClassAliasMapDFS(
+        typeRefPrefix: "${typeRefPrefix}_${(node.alias ?? node.name).value}",
+        getAliasTypeName: getAliasTypeName,
+        selections: node.selectionSet!.selections,
+        fragmentMap: fragmentMap,
+        aliasMap: aliasMap,
+      );
+    }
+  }
+}

codegen/gql_code_builder/lib/src/built_class.dart

@@ -11,6 +11,7 @@ Class builtClass({
   Map<String, Expression>? initializers,
   Map<String, SourceSelections> superclassSelections = const {},
   List<Method> methods = const [],
+  Map<String, Reference>? dataClassAliasMap,
 }) {
   final className = builtClassName(name);
   return Class(
@@ -30,12 +31,16 @@ Class builtClass({
                 ],
               ),
           ),
-          ...superclassSelections.keys.map<Reference>(
-            (superName) => refer(
-              builtClassName(superName),
-              (superclassSelections[superName]?.url ?? "") + "#data",
-            ),
-          )
+          ...superclassSelections.keys
+              .where((superName) =>
+                  dataClassAliasMap?.containsKey(builtClassName(superName)) !=
+                  true)
+              .map<Reference>(
+                (superName) => refer(
+                  builtClassName(superName),
+                  (superclassSelections[superName]?.url ?? "") + "#data",
+                ),
+              )
         ],
       )
       ..constructors.addAll(

codegen/gql_code_builder/lib/src/common.dart

@@ -138,6 +138,7 @@ Method buildGetter({
   required TypeNode typeNode,
   required SourceNode schemaSource,
   Map<String, Reference> typeOverrides = const {},
+  Reference? typeRefAlias,
   String? typeRefPrefix,
   bool built = true,
   bool isOverride = false,
@@ -151,7 +152,9 @@ Method buildGetter({
 
   final typeMap = {
     ...defaultTypeMap,
-    if (typeRefPrefix != null)
+    if (typeRefAlias != null)
+      typeName: typeRefAlias
+    else if (typeRefPrefix != null)
       typeName: refer("${typeRefPrefix}_${nameNode.value}")
     else if (typeDef != null)
       typeName: refer(

codegen/gql_code_builder/lib/src/config/data_class_config.dart

@@ -0,0 +1,8 @@
+/// config for the optimization of data class generation.
+class DataClassConfig {
+  final bool reuseFragments;
+
+  const DataClassConfig({
+    required this.reuseFragments,
+  });
+}