Migrate shared_preferences_platform_interfaces to null safety (#3466)

packages/shared_preferences/shared_preferences_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.0.0-nullsafety
+
+* Migrate to null safety.
+
 ## 1.0.5
 
 * Update Flutter SDK constraint.

packages/shared_preferences/shared_preferences_platform_interface/lib/method_channel_shared_preferences.dart

@@ -18,39 +18,32 @@ const MethodChannel _kChannel =
 class MethodChannelSharedPreferencesStore
     extends SharedPreferencesStorePlatform {
   @override
-  Future<bool> remove(String key) {
-    return _invokeBoolMethod('remove', <String, dynamic>{
-      'key': key,
-    });
+  Future<bool> remove(String key) async {
+    return (await _kChannel.invokeMethod<bool>(
+      'remove',
+      <String, dynamic>{'key': key},
+    ))!;
   }
 
   @override
-  Future<bool> setValue(String valueType, String key, Object value) {
-    return _invokeBoolMethod('set$valueType', <String, dynamic>{
-      'key': key,
-      'value': value,
-    });
-  }
-
-  Future<bool> _invokeBoolMethod(String method, Map<String, dynamic> params) {
-    return _kChannel
-        .invokeMethod<bool>(method, params)
-        // TODO(yjbanov): I copied this from the original
-        //                shared_preferences.dart implementation, but I
-        //                actually do not know why it's necessary to pipe the
-        //                result through an identity function.
-        //
-        //                Source: https://github.com/flutter/plugins/blob/3a87296a40a2624d200917d58f036baa9fb18df8/packages/shared_preferences/lib/shared_preferences.dart#L134
-        .then<bool>((dynamic result) => result);
+  Future<bool> setValue(String valueType, String key, Object value) async {
+    return (await _kChannel.invokeMethod<bool>(
+      'set$valueType',
+      <String, dynamic>{'key': key, 'value': value},
+    ))!;
   }
 
   @override
-  Future<bool> clear() {
-    return _kChannel.invokeMethod<bool>('clear');
+  Future<bool> clear() async {
+    return (await _kChannel.invokeMethod<bool>('clear'))!;
   }
 
   @override
-  Future<Map<String, Object>> getAll() {
-    return _kChannel.invokeMapMethod<String, Object>('getAll');
+  Future<Map<String, Object>> getAll() async {
+    final Map<String, Object>? preferences =
+        await _kChannel.invokeMapMethod<String, Object>('getAll');
+
+    if (preferences == null) return <String, Object>{};
+    return preferences;
   }
 }

packages/shared_preferences/shared_preferences_platform_interface/lib/shared_preferences_platform_interface.dart

@@ -4,7 +4,7 @@
 
 import 'dart:async';
 
-import 'package:meta/meta.dart';
+import 'package:flutter/foundation.dart';
 
 import 'method_channel_shared_preferences.dart';
 

packages/shared_preferences/shared_preferences_platform_interface/pubspec.yaml

@@ -1,18 +1,17 @@
 name: shared_preferences_platform_interface
 description: A common platform interface for the shared_preferences plugin.
 homepage: https://github.com/flutter/plugins/tree/master/packages/shared_preferences/shared_preferences_platform_interface
-version: 1.0.5
+version: 2.0.0-nullsafety
 
 dependencies:
-  meta: ^1.0.4
   flutter:
     sdk: flutter
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0-nullsafety
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
   flutter: ">=1.12.8"

packages/shared_preferences/shared_preferences_platform_interface/test/method_channel_shared_preferences_test.dart

@@ -15,18 +15,18 @@ void main() {
       'plugins.flutter.io/shared_preferences',
     );
 
-    const Map<String, dynamic> kTestValues = <String, dynamic>{
+    const Map<String, Object> kTestValues = <String, Object>{
       'flutter.String': 'hello world',
       'flutter.Bool': true,
       'flutter.Int': 42,
       'flutter.Double': 3.14159,
       'flutter.StringList': <String>['foo', 'bar'],
     };
 
-    InMemorySharedPreferencesStore testData;
+    late InMemorySharedPreferencesStore testData;
 
     final List<MethodCall> log = <MethodCall>[];
-    MethodChannelSharedPreferencesStore store;
+    late MethodChannelSharedPreferencesStore store;
 
     setUp(() async {
       testData = InMemorySharedPreferencesStore.empty();
@@ -44,9 +44,9 @@ void main() {
           return await testData.clear();
         }
         final RegExp setterRegExp = RegExp(r'set(.*)');
-        final Match match = setterRegExp.matchAsPrefix(methodCall.method);
-        if (match.groupCount == 1) {
-          final String valueType = match.group(1);
+        final Match? match = setterRegExp.matchAsPrefix(methodCall.method);
+        if (match?.groupCount == 1) {
+          final String valueType = match!.group(1)!;
           final String key = methodCall.arguments['key'];
           final Object value = methodCall.arguments['value'];
           return await testData.setValue(valueType, key, value);
@@ -59,8 +59,6 @@ void main() {
 
     tearDown(() async {
       await testData.clear();
-      store = null;
-      testData = null;
     });
 
     test('getAll', () async {

script/nnbd_plugins.sh

@@ -17,6 +17,7 @@ readonly NNBD_PLUGINS_LIST=(
   "path_provider"
   "plugin_platform_interface"
   "share"
+  "shared_preferences"
   "url_launcher"
   "video_player"
   "webview_flutter"
@@ -35,7 +36,6 @@ readonly NON_NNBD_PLUGINS_LIST=(
   # "in_app_purchase"
   # "quick_actions"
   # "sensors"
-  # "shared_preferences"
   # "wifi_info_flutter"
 )