Apply null-safety migration changes

Author: justshreyas

example/pubspec.lock

@@ -7,42 +7,42 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.6.1"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
+    version: "1.15.0"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -56,7 +56,7 @@ packages:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -80,21 +80,21 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -106,56 +106,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.1"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.3.0"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
+  dart: ">=2.12.0 <3.0.0"
   flutter: ">=1.20.0"

lib/flutter_split.dart

@@ -18,7 +18,7 @@ class FlutterSplit {
     }
   }
 
-  Future<String> getTreatment(String key, Map<String, dynamic> attr) async {
+  Future<String?> getTreatment(String key, Map<String, dynamic> attr) async {
     Map<String, dynamic> attributes = {"key": key, "attributes": attr};
 
     try {
@@ -30,7 +30,7 @@ class FlutterSplit {
     }
   }
 
-  Future<SplitResult> getTreatmentWithConfig(
+  Future<SplitResult?> getTreatmentWithConfig(
       String key, Map<String, dynamic> attr) async {
     Map<String, dynamic> attributes = {"key": key, "attributes": attr};
 
@@ -49,13 +49,13 @@ class FlutterSplit {
     }
   }
 
-  Future<Map<String, String>> getTreatments(
+  Future<Map<String, String?>> getTreatments(
       List<String> keys, Map<String, dynamic> attr) async {
     Map<String, dynamic> attributes = {"keys": keys, "attributes": attr};
 
     var data = await _channel.invokeMethod('getTreatments', attributes);
 
-    Map<String, String> result = Map();
+    Map<String, String?> result = Map();
     for (var key in keys) {
       try {
         result[key] = data[key];
@@ -96,7 +96,7 @@ class FlutterSplit {
     return await _channel.invokeMethod('dispose');
   }
 
-  Future<bool> trackEvent(
+  Future<bool?> trackEvent(
       String eventType, String trafficType, Map<String, dynamic> props) async {
     return await _channel.invokeMethod('trackEvent', {
       'trafficType': trafficType,

lib/split_result.dart

@@ -1,7 +1,7 @@
 class SplitResult {
-  String splitName;
-  String treatment;
-  Map<String, dynamic> config;
+  String? splitName;
+  String? treatment;
+  Map<String, dynamic>? config;
 
   SplitResult.fromJson(json) {
     this.splitName = json['splitName'];

pubspec.yaml

@@ -5,7 +5,7 @@ author:
 homepage:
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
   flutter: ">=1.20.0"
 
 dependencies: