Refactor SDK index construction: removing mutable state.

app/lib/search/dart_sdk_mem_index.dart

@@ -4,7 +4,6 @@
 
 import 'package:gcloud/service_scope.dart' as ss;
 import 'package:logging/logging.dart';
-import 'package:meta/meta.dart';
 
 import 'backend.dart';
 import 'sdk_mem_index.dart';
@@ -14,7 +13,6 @@ final _logger = Logger('search.dart_sdk_mem_index');
 /// Results from these libraries are ranked with lower score and
 /// will be displayed only if the query has the library name, or
 /// there are not other results that could match the query.
-@visibleForTesting
 const dartSdkLibraryWeights = <String, double>{
   'dart:html': 0.7,
 };
@@ -37,14 +35,9 @@ SdkMemIndex? get dartSdkMemIndex =>
 /// was an error parsing the file or building the index.
 Future<SdkMemIndex?> createDartSdkMemIndex() async {
   try {
-    final index = await SdkMemIndex.dart();
-    final content = await loadOrFetchSdkIndexJsonAsString(index.indexJsonUri);
-    await index.addDartdocIndex(DartdocIndex.parseJsonText(content));
-    index.updateWeights(
-      libraryWeights: dartSdkLibraryWeights,
-      apiPageDirWeights: {},
-    );
-    return index;
+    final content =
+        await loadOrFetchSdkIndexJsonAsString(SdkMemIndex.dartSdkIndexJsonUri);
+    return SdkMemIndex.dart(index: DartdocIndex.parseJsonText(content));
   } catch (e, st) {
     _logger.warning('Unable to load Dart SDK index.', e, st);
     return null;

app/lib/search/flutter_sdk_mem_index.dart

@@ -12,7 +12,7 @@ import 'sdk_mem_index.dart';
 /// regular packages. The selected libraries are unique to the index.json.
 ///
 /// TODO: try to find a way to derive this list automatically.
-const _allowedLibraries = <String>{
+const flutterSdkAllowedLibraries = <String>{
   'dart:ui',
   'animation',
   'cupertino',
@@ -32,7 +32,7 @@ const _allowedLibraries = <String>{
   'flutter_web_plugins',
 };
 
-const _flutterApiPageDirWeights = <String, double>{
+const flutterApiPageDirWeights = <String, double>{
   'cupertino/CupertinoIcons': 0.25,
   'material/Icons': 0.25,
 };
@@ -54,14 +54,10 @@ SdkMemIndex? get flutterSdkMemIndex =>
 /// api.flutter.dev and returns search results based on [SdkMemIndex].
 Future<SdkMemIndex?> createFlutterSdkMemIndex() async {
   try {
-    final index = SdkMemIndex.flutter();
-    final content = await loadOrFetchSdkIndexJsonAsString(index.indexJsonUri);
-    await index.addDartdocIndex(DartdocIndex.parseJsonText(content),
-        allowedLibraries: _allowedLibraries);
-    index.updateWeights(
-      libraryWeights: {},
-      apiPageDirWeights: _flutterApiPageDirWeights,
-    );
+    final content = await loadOrFetchSdkIndexJsonAsString(
+        SdkMemIndex.flutterSdkIndexJsonUri);
+    final index =
+        SdkMemIndex.flutter(index: DartdocIndex.parseJsonText(content));
     return index;
   } catch (e, st) {
     _logger.warning('Unable to load Flutter SDK index.', e, st);

app/lib/search/sdk_mem_index.dart

@@ -8,6 +8,8 @@ import 'package:meta/meta.dart';
 // ignore: implementation_imports
 import 'package:pana/src/dartdoc/dartdoc_index.dart';
 import 'package:path/path.dart' as p;
+import 'package:pub_dev/search/dart_sdk_mem_index.dart';
+import 'package:pub_dev/search/flutter_sdk_mem_index.dart';
 
 import '../shared/versions.dart';
 import 'search_service.dart';
@@ -23,39 +25,55 @@ class SdkMemIndex {
   final _tokensPerLibrary = <String, TokenIndex<String>>{};
   final _baseUriPerLibrary = <String, String>{};
   final _descriptionPerLibrary = <String, String>{};
-  final _libraryWeights = <String, double>{};
-  final _apiPageDirWeights = <String, double>{};
+  final Map<String, double> _libraryWeights;
+  final Map<String, double> _apiPageDirWeights;
 
   SdkMemIndex({
     required String sdk,
     required String? version,
     required Uri baseUri,
+    required DartdocIndex index,
+    Set<String>? allowedLibraries,
+    Map<String, double>? libraryWeights,
+    Map<String, double>? apiPageDirWeights,
   })  : _sdk = sdk,
         _version = version,
-        _baseUri = baseUri;
+        _baseUri = baseUri,
+        _libraryWeights = libraryWeights ?? const {},
+        _apiPageDirWeights = apiPageDirWeights ?? const {} {
+    _addDartdocIndex(index, allowedLibraries);
+  }
 
-  static Future<SdkMemIndex> dart() async {
+  static SdkMemIndex dart({required DartdocIndex index}) {
     return SdkMemIndex(
       sdk: 'dart',
       version: runtimeSdkVersion,
       baseUri: Uri.parse('https://api.dart.dev/stable/latest/'),
+      index: index,
+      libraryWeights: dartSdkLibraryWeights,
     );
   }
 
-  factory SdkMemIndex.flutter() {
+  factory SdkMemIndex.flutter({required DartdocIndex index}) {
     return SdkMemIndex(
       sdk: 'flutter',
       version: null,
       baseUri: Uri.parse('https://api.flutter.dev/flutter/'),
+      index: index,
+      allowedLibraries: flutterSdkAllowedLibraries,
+      apiPageDirWeights: flutterApiPageDirWeights,
     );
   }
 
-  late final indexJsonUri = _baseUri.resolve('index.json');
+  static final dartSdkIndexJsonUri =
+      Uri.parse('https://api.dart.dev/stable/latest/index.json');
+  static final flutterSdkIndexJsonUri =
+      Uri.parse('https://api.flutter.dev/flutter/index.json');
 
-  Future<void> addDartdocIndex(
-    DartdocIndex index, {
+  void _addDartdocIndex(
+    DartdocIndex index,
     Set<String>? allowedLibraries,
-  }) async {
+  ) {
     final textsPerLibrary = <String, Map<String, String>>{};
     for (final f in index.entries) {
       final library = f.qualifiedName?.split('.').first;
@@ -86,15 +104,6 @@ class SdkMemIndex {
     }
   }
 
-  /// Updates the non-default weight for libraries.
-  void updateWeights({
-    required Map<String, double> libraryWeights,
-    required Map<String, double> apiPageDirWeights,
-  }) {
-    _libraryWeights.addAll(libraryWeights);
-    _apiPageDirWeights.addAll(apiPageDirWeights);
-  }
-
   List<SdkLibraryHit> search(
     String query, {
     int? limit,

app/test/search/backend_test.dart

@@ -13,9 +13,10 @@ import '../shared/test_services.dart';
 void main() {
   group('search backend', () {
     testWithProfile('fetch SDK library description', fn: () async {
-      final index = await SdkMemIndex.dart();
-      final content = await loadOrFetchSdkIndexJsonAsString(index.indexJsonUri);
-      await index.addDartdocIndex(DartdocIndex.parseJsonText(content));
+      final content = await loadOrFetchSdkIndexJsonAsString(
+          SdkMemIndex.dartSdkIndexJsonUri);
+      final index =
+          SdkMemIndex.dart(index: DartdocIndex.parseJsonText(content));
       expect(
         index.getLibraryDescription('dart:async'),
         'Support for asynchronous programming, with classes such as Future and Stream.',

app/test/search/dartdoc_index_parsing_test.dart

@@ -66,8 +66,7 @@ void main() {
       expect(parserWithoutFirstEntry, originalWithoutFirstEntry);
 
       // parsing into SDK index
-      final sdkMemIndex = SdkMemIndex.flutter();
-      await sdkMemIndex.addDartdocIndex(index);
+      final sdkMemIndex = SdkMemIndex.flutter(index: index);
       final rs = sdkMemIndex.search('StatelessWidget');
       expect(json.decode(json.encode(rs)), [
         {

app/test/search/result_combiner_test.dart

@@ -31,49 +31,48 @@ void main() {
     final combiner = SearchResultCombiner(
       primaryIndex: primaryIndex,
       dartSdkMemIndex: SdkMemIndex(
-          sdk: 'dart',
-          version: runtimeSdkVersion,
-          baseUri: Uri.parse('https://api.dart.dev/stable/$runtimeSdkVersion/'))
-        ..addDartdocIndex(
-          DartdocIndex.fromJsonList([
-            {
-              'name': 'dart:core',
-              'qualifiedName': 'dart:core',
-              'href': 'dart-core/dart-core-library.html',
-              'kind': 8,
-              'overriddenDepth': 0,
-              'packageName': 'Dart'
-            },
-            {
-              'name': 'String',
-              'qualifiedName': 'dart:core.String',
-              'href': 'dart-core/String-class.html',
-              'kind': 3,
-              'overriddenDepth': 0,
-              'packageName': 'Dart',
-              'enclosedBy': {'name': 'dart:core', 'kind': 8}
-            },
-            {
-              'name': 'substring',
-              'qualifiedName': 'dart:core.String.substring',
-              'href': 'dart-core/String/substring.html',
-              'kind': 9,
-              'overriddenDepth': 0,
-              'packageName': 'Dart',
-              'enclosedBy': {'name': 'String', 'kind': 3}
-            },
-            {
-              // fake method for checking the package name matches
-              'name': 'stringutils',
-              'qualifiedName': 'dart:core.String.stringutils',
-              'href': 'dart-core/String/stringutils.html',
-              'kind': 9,
-              'overriddenDepth': 0,
-              'packageName': 'Dart',
-              'enclosedBy': {'name': 'String', 'kind': 3}
-            },
-          ]),
-        ),
+        sdk: 'dart',
+        version: runtimeSdkVersion,
+        baseUri: Uri.parse('https://api.dart.dev/stable/$runtimeSdkVersion/'),
+        index: DartdocIndex.fromJsonList([
+          {
+            'name': 'dart:core',
+            'qualifiedName': 'dart:core',
+            'href': 'dart-core/dart-core-library.html',
+            'kind': 8,
+            'overriddenDepth': 0,
+            'packageName': 'Dart'
+          },
+          {
+            'name': 'String',
+            'qualifiedName': 'dart:core.String',
+            'href': 'dart-core/String-class.html',
+            'kind': 3,
+            'overriddenDepth': 0,
+            'packageName': 'Dart',
+            'enclosedBy': {'name': 'dart:core', 'kind': 8}
+          },
+          {
+            'name': 'substring',
+            'qualifiedName': 'dart:core.String.substring',
+            'href': 'dart-core/String/substring.html',
+            'kind': 9,
+            'overriddenDepth': 0,
+            'packageName': 'Dart',
+            'enclosedBy': {'name': 'String', 'kind': 3}
+          },
+          {
+            // fake method for checking the package name matches
+            'name': 'stringutils',
+            'qualifiedName': 'dart:core.String.stringutils',
+            'href': 'dart-core/String/stringutils.html',
+            'kind': 9,
+            'overriddenDepth': 0,
+            'packageName': 'Dart',
+            'enclosedBy': {'name': 'String', 'kind': 3}
+          },
+        ]),
+      ),
       flutterSdkMemIndex: null,
     );