Migrate cupertino_store to null safety

cupertino_store/step_00/pubspec.lock

@@ -7,42 +7,42 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.3"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.5"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.3"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.5"
+    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.3"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -73,56 +73,56 @@ packages:
       name: intl
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.16.1"
+    version: "0.17.0"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.3"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.6"
+    version: "1.3.0"
   nested:
     dependency: transitive
     description:
       name: nested
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4"
+    version: "1.0.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.3"
+    version: "1.8.0"
   pedantic:
     dependency: "direct dev"
     description:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.2"
+    version: "1.10.0"
   provider:
     dependency: "direct main"
     description:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "4.3.2+4"
+    version: "5.0.0-nullsafety.4"
   shrine_images:
     dependency: "direct main"
     description:
       name: shrine_images
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "2.0.1"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -134,56 +134,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.4"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.6"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.3"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.6"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.5"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.5"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.12.0-0.0 <3.0.0"
+  dart: ">=2.12.0-259.8.beta <3.0.0"
   flutter: ">=1.16.0"

cupertino_store/step_00/pubspec.yaml

@@ -18,20 +18,20 @@ publish_to: "none" # Remove this line if you wish to publish to pub.dev
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0-259.8.beta <3.0.0"
 
 dependencies:
-  cupertino_icons: ^1.0.0
+  cupertino_icons: ^1.0.2
   flutter:
     sdk: flutter
-  intl: ^0.16.1
-  provider: ^4.1.1
-  shrine_images: ^1.0.0
+  intl: ^0.17.0
+  provider: ^5.0.0-0
+  shrine_images: ^2.0.1
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pedantic: ^1.9.0
+  pedantic: ^1.10.0
 
 flutter:
   assets:

cupertino_store/step_01/lib/app.dart

@@ -54,7 +54,7 @@ class CupertinoStoreHomePage extends StatelessWidget {
         ],
       ),
       tabBuilder: (context, index) {
-        CupertinoTabView returnValue;
+        late final CupertinoTabView returnValue;
         switch (index) {
           case 0:
             returnValue = CupertinoTabView(builder: (context) {

cupertino_store/step_01/lib/model/app_state_model.dart

@@ -22,7 +22,7 @@ double _shippingCostPerItem = 7;
 
 class AppStateModel extends foundation.ChangeNotifier {
   // All the available products.
-  List<Product> _availableProducts;
+  List<Product> _availableProducts = [];
 
   // The currently selected category of products.
   Category _selectedCategory = Category.all;
@@ -49,7 +49,7 @@ class AppStateModel extends foundation.ChangeNotifier {
   double get subtotalCost {
     return _productsInCart.keys.map((id) {
       // Extended price for product line
-      return getProductById(id).price * _productsInCart[id];
+      return getProductById(id).price * _productsInCart[id]!;
     }).fold(0, (accumulator, extendedPrice) {
       return accumulator + extendedPrice;
     });
@@ -75,10 +75,6 @@ class AppStateModel extends foundation.ChangeNotifier {
 
   // Returns a copy of the list of available products, filtered by category.
   List<Product> getProducts() {
-    if (_availableProducts == null) {
-      return [];
-    }
-
     if (_selectedCategory == Category.all) {
       return List.from(_availableProducts);
     } else {
@@ -100,7 +96,7 @@ class AppStateModel extends foundation.ChangeNotifier {
     if (!_productsInCart.containsKey(productId)) {
       _productsInCart[productId] = 1;
     } else {
-      _productsInCart[productId]++;
+      _productsInCart[productId] = _productsInCart[productId]! + 1;
     }
 
     notifyListeners();
@@ -112,7 +108,7 @@ class AppStateModel extends foundation.ChangeNotifier {
       if (_productsInCart[productId] == 1) {
         _productsInCart.remove(productId);
       } else {
-        _productsInCart[productId]--;
+        _productsInCart[productId] = _productsInCart[productId]! - 1;
       }
     }
 

cupertino_store/step_01/lib/model/product.dart

@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'package:flutter/foundation.dart';
-
 enum Category {
   all,
   accessories,
@@ -23,16 +21,12 @@ enum Category {
 
 class Product {
   const Product({
-    @required this.category,
-    @required this.id,
-    @required this.isFeatured,
-    @required this.name,
-    @required this.price,
-  })  : assert(category != null, 'category must not be null'),
-        assert(id != null, 'id must not be null'),
-        assert(isFeatured != null, 'isFeatured must not be null'),
-        assert(name != null, 'name must not be null'),
-        assert(price != null, 'price must not be null');
+    required this.category,
+    required this.id,
+    required this.isFeatured,
+    required this.name,
+    required this.price,
+  });
 
   final Category category;
   final int id;