Merge pull request #2360 from arjundevlucid/master

Fixed backward compatibility

 typedef ValueUpdater<T> = T Function();
+/// This allows a value of type T or T?
+/// to be treated as a value of type T?.
+///
+/// We use this so that APIs that have become
+/// non-nullable can still be used with `!` and `?`
+/// to support older versions of the API as well.
+T? ambiguate<T>(T? value) => value;

 import 'package:flutter/foundation.dart';
 import 'package:flutter/scheduler.dart';
 
+import '../../get.dart';
+
 /// The [GetLifeCycle]
 ///
 /// ```dart
@@ -16,7 +18,8 @@ mixin GetLifeCycleMixin {
   @protected
   @mustCallSuper
   void onInit() {
-    SchedulerBinding.instance?.addPostFrameCallback((_) => onReady());
+    ambiguate(SchedulerBinding.instance)
+        ?.addPostFrameCallback((_) => onReady());
   }
 
   /// Called 1 frame after onInit(). It is the perfect place to enter

@@ -358,7 +358,7 @@ extension ExtensionSnackbar on GetInterface {
     if (instantInit) {
       controller.show();
     } else {
-      SchedulerBinding.instance!.addPostFrameCallback((_) {
+      ambiguate(SchedulerBinding.instance)!.addPostFrameCallback((_) {
         controller.show();
       });
     }
@@ -469,7 +469,7 @@ extension ExtensionSnackbar on GetInterface {
       controller.show();
     } else {
       //routing.isSnackbar = true;
-      SchedulerBinding.instance!.addPostFrameCallback((_) {
+      ambiguate(SchedulerBinding.instance)!.addPostFrameCallback((_) {
         controller.show();
       });
     }
@@ -544,8 +544,10 @@ extension GetNavigationExt on GetInterface {
 //       return page;
 //     } else if (page is Widget) {
 //       Get.log(
-//           '''WARNING, consider using: "Get.$method(() => Page())" instead of "Get.$method(Page())".
-// Using a widget function instead of a widget fully guarantees that the widget and its controllers will be removed from memory when they are no longer used.
+//           '''WARNING, consider using: "Get.$method(() => Page())" 
+//instead of "Get.$method(Page())".
+// Using a widget function instead of a widget fully guarantees that the widget 
+//and its controllers will be removed from memory when they are no longer used.
 //       ''');
 //       return () => page;
 //     } else if (page is String) {

@@ -52,7 +52,7 @@ class RouterReportManager<T> {
 
   void reportRouteDispose(T disposed) {
     if (Get.smartManagement != SmartManagement.onlyBuilder) {
-      WidgetsBinding.instance!.addPostFrameCallback((_) {
+      ambiguate(WidgetsBinding.instance)!.addPostFrameCallback((_) {
         _removeDependencyByRoute(disposed);
       });
     }

@@ -34,6 +34,7 @@ class GetNavigator extends Navigator {
                 settings: settings,
               );
             }
+            return null;
           },
           reportsRouteUpdateToEngine: reportsRouteUpdateToEngine,
           restorationScopeId: restorationScopeId,

@@ -326,7 +326,8 @@ class GetDelegate extends RouterDelegate<RouteDecoder>
         PreventDuplicateHandlingMode.ReorderRoutes,
   }) async {
     routeName = _cleanRouteName("/${page.runtimeType}");
-    // if (preventDuplicateHandlingMode == PreventDuplicateHandlingMode.Recreate) {
+    // if (preventDuplicateHandlingMode ==
+    // PreventDuplicateHandlingMode.Recreate) {
     //   routeName = routeName + page.hashCode.toString();
     // }
 

@@ -449,7 +449,7 @@ You need to either use message[String], or messageText[Widget] or define a userI
   }
 
   void _configureLeftBarFuture() {
-    SchedulerBinding.instance!.addPostFrameCallback(
+    ambiguate(SchedulerBinding.instance)!.addPostFrameCallback(
       (_) {
         final keyContext = _backgroundBoxKey.currentContext;
         if (keyContext != null) {

@@ -248,18 +248,21 @@ extension RxnBoolExt on Rx<bool?> {
 
   bool? get isFalse {
     if (value != null) return !isTrue!;
+    return null;
   }
 
   bool? operator &(bool other) {
     if (value != null) {
       return other && value!;
     }
+    return null;
   }
 
   bool? operator |(bool other) {
     if (value != null) {
       return other || value!;
     }
+    return null;
   }
 
   bool? operator ^(bool other) => !other == value;

@@ -269,6 +269,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! * other;
     }
+    return null;
   }
 
   /// Euclidean modulo operator.
@@ -288,6 +289,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! % other;
     }
+    return null;
   }
 
   /// Division operator.
@@ -295,6 +297,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! / other;
     }
+    return null;
   }
 
   /// Truncating division operator.
@@ -308,6 +311,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! ~/ other;
     }
+    return null;
   }
 
   /// Negate operator.
@@ -315,6 +319,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return -value!;
     }
+    return null;
   }
 
   /// Returns the remainder of the truncating division of `this` by [other].
@@ -330,6 +335,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! < other;
     }
+    return null;
   }
 
   /// Relational less than or equal operator.
@@ -337,6 +343,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! <= other;
     }
+    return null;
   }
 
   /// Relational greater than operator.
@@ -344,6 +351,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! > other;
     }
+    return null;
   }
 
   /// Relational greater than or equal operator.
@@ -351,6 +359,7 @@ extension RxnNumExt<T extends num> on Rx<T?> {
     if (value != null) {
       return value! >= other;
     }
+    return null;
   }
 
   /// True if the number is the double Not-a-Number value; otherwise, false.
@@ -585,6 +594,7 @@ class RxnNum extends Rx<num?> {
       value = value! + other;
       return value;
     }
+    return null;
   }
 
   /// Subtraction operator.
@@ -593,6 +603,7 @@ class RxnNum extends Rx<num?> {
       value = value! - other;
       return value;
     }
+    return null;
   }
 }
 
@@ -711,6 +722,7 @@ extension RxnDoubleExt on Rx<double?> {
       value = value! + other;
       return this;
     }
+    return null;
   }
 
   /// Subtraction operator.
@@ -719,6 +731,7 @@ extension RxnDoubleExt on Rx<double?> {
       value = value! + other;
       return this;
     }
+    return null;
   }
 
   /// Multiplication operator.
@@ -726,12 +739,14 @@ extension RxnDoubleExt on Rx<double?> {
     if (value != null) {
       return value! * other;
     }
+    return null;
   }
 
   double? operator %(num other) {
     if (value != null) {
       return value! % other;
     }
+    return null;
   }
 
   /// Division operator.
@@ -739,6 +754,7 @@ extension RxnDoubleExt on Rx<double?> {
     if (value != null) {
       return value! / other;
     }
+    return null;
   }
 
   /// Truncating division operator.
@@ -749,6 +765,7 @@ extension RxnDoubleExt on Rx<double?> {
     if (value != null) {
       return value! ~/ other;
     }
+    return null;
   }
 
   /// Negate operator. */
@@ -756,6 +773,7 @@ extension RxnDoubleExt on Rx<double?> {
     if (value != null) {
       return -value!;
     }
+    return null;
   }
 
   /// Returns the absolute value of this [double].
@@ -1104,6 +1122,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return value! & other;
     }
+    return null;
   }
 
   /// Bit-wise or operator.
@@ -1118,6 +1137,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return value! | other;
     }
+    return null;
   }
 
   /// Bit-wise exclusive-or operator.
@@ -1132,6 +1152,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return value! ^ other;
     }
+    return null;
   }
 
   /// The bit-wise negate operator.
@@ -1144,6 +1165,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return ~value!;
     }
+    return null;
   }
 
   /// Shift the bits of this integer to the left by [shiftAmount].
@@ -1160,6 +1182,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return value! << shiftAmount;
     }
+    return null;
   }
 
   /// Shift the bits of this integer to the right by [shiftAmount].
@@ -1173,6 +1196,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return value! >> shiftAmount;
     }
+    return null;
   }
 
   /// Returns this integer to the power of [exponent] modulo [modulus].
@@ -1290,6 +1314,7 @@ extension RxnIntExt on Rx<int?> {
     if (value != null) {
       return -value!;
     }
+    return null;
   }
 
   /// Returns the absolute value of this integer.

@@ -96,13 +96,13 @@ mixin FullLifeCycleMixin on FullLifeCycleController {
   @override
   void onInit() {
     super.onInit();
-    WidgetsBinding.instance!.addObserver(this);
+    ambiguate(WidgetsBinding.instance)!.addObserver(this);
   }
 
   @mustCallSuper
   @override
   void onClose() {
-    WidgetsBinding.instance!.removeObserver(this);
+    ambiguate(WidgetsBinding.instance)!.removeObserver(this);
     super.onClose();
   }
 

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
 
+import '../../../get_core/src/typedefs.dart';
 import 'list_notifier.dart';
 
 typedef ValueBuilderUpdateCallback<T> = void Function(T snapshot);
@@ -102,13 +103,14 @@ mixin ObserverComponent on ComponentElement {
 
   Future<bool> _safeRebuild() async {
     if (dirty) return false;
-    if (SchedulerBinding.instance == null) {
+    if (ambiguate(SchedulerBinding.instance) == null) {
       markNeedsBuild();
     } else {
       // refresh was called during the building
-      if (SchedulerBinding.instance!.schedulerPhase != SchedulerPhase.idle) {
+      if (ambiguate(SchedulerBinding.instance)!.schedulerPhase 
+      != SchedulerPhase.idle) {
         // Await for the end of build
-        await SchedulerBinding.instance!.endOfFrame;
+        await ambiguate(SchedulerBinding.instance)!.endOfFrame;
         if (dirty) return false;
       }
 

 void main() {
-  // testWidgets('Back swipe dismiss interrupted by route push', (tester) async {
+  // testWidgets('Back swipe dismiss interrupted by route push',
+  // (tester) async {
   //   // final scaffoldKey = GlobalKey();
 
   //   await tester.pumpWidget(
@@ -59,7 +60,8 @@ void main() {
   //   expect(find.text('push'), findsOneWidget);
   //   expect(
   //     tester.getTopLeft(find.ancestor(
-  //         of: find.text('push'), matching: find.byType(CupertinoPageScaffold))),
+  //         of: find.text('push'),
+  // matching: find.byType(CupertinoPageScaffold))),
   //     Offset.zero,
   //   );
   //   expect(find.text('route'), findsNothing);