feat!: null safety (rrousselGit#574)

.github/workflows/build.yml

@@ -17,10 +17,9 @@ jobs:
         channel:
           - dev
           - beta
-          - stable
 
     steps:
       - uses: actions/checkout@v2
 
       - name: Execute test script
-        run: curl -s https://raw.githubusercontent.com/rrousselGit/ci/master/scripts/ci.sh | bash
+        run: curl -s https://raw.githubusercontent.com/rrousselGit/ci/master/scripts/ci.sh | bash -s nnbd

CHANGELOG.md

@@ -1,3 +1,74 @@
+# 5.0.0-nullsafety.4
+
+- Upgraded `nested` dependency to 1.0.0 and `collection` to 1.15.0
+
+# 5.0.0-nullsafety.3
+
+- Improved the error message of `ProviderNotFoundException` to mention hot-reload. (#595)
+- Removed the asserts that prevented `ChangeNotifier`s in `ChangeNotifierProvider()`
+  to have listeners (#596)
+- Removed the opinionated asserts in `context.watch`/`context.read`
+  that prevented them to be used inside specific conditions (#585)
+
+# 5.0.0-nullsafety.2
+
+- Improved the error message when an exception is thrown inside `create` of a provider`
+
+# 5.0.0-nullsafety.1
+
+- Reintroduced `ValueListenableProvider.value` (the default constructor is still removed).
+
+# 5.0.0-nullsafety.0
+
+Migrated Provider to non-nullable types:
+
+- `initialData` for both `FutureProvider` and `StreamProvider` is now required.
+
+  To migrate, what used to be:
+
+  ```dart
+  FutureProvider<int>(
+    create: (context) => Future.value(42),
+    child: MyApp(),
+  )
+
+  Widget build(BuildContext context) {
+    final value = context.watch<int>();
+    return Text('$value');
+  }
+  ```
+
+  is now:
+
+  ```dart
+  FutureProvider<int?>(
+    initialValue: null,
+    create: (context) => Future.value(42),
+    child: MyApp(),
+  )
+
+  Widget build(BuildContext context) {
+    // be sure to specify the ? in watch<int?>
+    final value = context.watch<int?>();
+    return Text('$value');
+  }
+  ```
+
+- `ValueListenableProvider` is removed
+
+  To migrate, you can instead use `Provider` combined with `ValueListenableBuilder`:
+
+  ```dart
+  ValueListenableBuilder<int>(
+    valueListenable: myValueListenable,
+    builder: (context, value, _) {
+      return Provider<int>.value(
+        value: value,
+        child: MyApp(),
+      );
+    }
+  )
+  ```
 # 4.3.3
 
 - Improved the error message of `ProviderNotFoundException` to mention hot-reload. (#595)

README.md

@@ -26,51 +26,56 @@ See also:
 - [flutter architecture sample](https://github.com/brianegan/flutter_architecture_samples/tree/master/change_notifier_provider), which contains an implementation of that app using `provider` + [ChangeNotifier]
 - [flutter_bloc](https://github.com/felangel/bloc) and [Mobx](https://github.com/mobxjs/mobx.dart), which use `provider` in their architecture
 
-## Migration from v3.x.0 to v4.0.0
+## Migration from 4.x.x to 5.0.0-nullsafety
 
-- The parameters `builder` and `initialBuilder` of providers are removed.
+- `initialData` for both `FutureProvider` and `StreamProvider` is now required.
 
-  - `initialBuilder` should be replaced by `create`.
-  - `builder` of "proxy" providers should be replaced by `update`
-  - `builder` of classical providers should be replaced by `create`.
-
-- The new `create`/`update` callbacks are lazy-loaded, which means they are called
-  the first time the value is read instead of the first time the provider is created.
-
-  If this is undesired, you can disable lazy-loading by passing `lazy: false` to
-  the provider of your choice:
+  To migrate, what used to be:
 
   ```dart
-  FutureProvider(
-    create: (_) async => doSomeHttpRequest(),
-    lazy: false,
-    child: ...
+  FutureProvider<int>(
+    create: (context) => Future.value(42),
+    child: MyApp(),
   )
+
+  Widget build(BuildContext context) {
+    final value = context.watch<int>();
+    return Text('$value');
+  }
   ```
 
-- `ProviderNotFoundError` is renamed to `ProviderNotFoundException`.
+  is now:
 
-- The `SingleChildCloneableWidget` interface is removed and replaced by a new kind
-  of widget `SingleChildWidget`.
+  ```dart
+  FutureProvider<int?>(
+    initialValue: null,
+    create: (context) => Future.value(42),
+    child: MyApp(),
+  )
 
-  See [this issue](https://github.com/rrousselGit/provider/issues/237) for details
-  on how to migrate.
+  Widget build(BuildContext context) {
+    // be sure to specify the ? in watch<int?>
+    final value = context.watch<int?>();
+    return Text('$value');
+  }
+  ```
 
-- [Selector] now deeply compares the previous and new values if they are collections.
+- `ValueListenableProvider` is removed
 
-  If this is undesired, you can revert to the old behavior by passing a `shouldRebuild`
-  parameter to [Selector]:
+  To migrate, you can instead use `Provider` combined with `ValueListenableBuilder`:
 
   ```dart
-  Selector<Selected, Consumed>(
-    shouldRebuild: (previous, next) => previous == next,
-    builder: ...,
+  ValueListenableBuilder<int>(
+    valueListenable: myValueListenable,
+    builder: (context, value, _) {
+      return Provider<int>.value(
+        value: value,
+        child: MyApp(),
+      );
+    }
   )
   ```
 
-- `DelegateWidget` and its family is removed. Instead, for custom providers,
-  directly subclass [InheritedProvider] or an existing provider.
-
 ## Usage
 
 ### Exposing a value

example/lib/main.dart

@@ -39,7 +39,7 @@ class Counter with ChangeNotifier, DiagnosticableTreeMixin {
 }
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key key}) : super(key: key);
+  const MyApp({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -50,7 +50,7 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatelessWidget {
-  const MyHomePage({Key key}) : super(key: key);
+  const MyHomePage({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -88,7 +88,7 @@ class MyHomePage extends StatelessWidget {
 }
 
 class Count extends StatelessWidget {
-  const Count({Key key}) : super(key: key);
+  const Count({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/pubspec.yaml

@@ -5,7 +5,7 @@ author: Remi Rousselet <[email protected]>
 publish_to: "none"
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0-0.0.dev <3.0.0"
 
 dependencies:
   flutter:

example/test_driver/app_test.dart

@@ -1,10 +1,10 @@
-// Imports the Flutter Driver API.
+// ignore: import_of_legacy_library_into_null_safe
 import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart';
 
 void main() {
   group('counter app', () {
-    FlutterDriver _driver;
+    FlutterDriver? _driver;
 
     final incrementFloatingButton =
         find.byValueKey('increment_floatingActionButton');
@@ -22,21 +22,21 @@ void main() {
     });
 
     test('AppBar is Flutter Demo Home Page', () async {
-      expect(await _driver.getText(appBarText), 'Example');
+      expect(await _driver!.getText(appBarText), 'Example');
     });
 
     test('counterText is started with 0', () async {
-      expect(await _driver.getText(counterState), '0');
+      expect(await _driver!.getText(counterState), '0');
     });
 
     test('pressed increment floating action button twice', () async {
       // tap floating action button
-      await _driver.tap(incrementFloatingButton);
-      expect(await _driver.getText(counterState), '1');
+      await _driver!.tap(incrementFloatingButton);
+      expect(await _driver!.getText(counterState), '1');
 
       // tap floating action button
-      await _driver.tap(incrementFloatingButton);
-      expect(await _driver.getText(counterState), '2');
+      await _driver!.tap(incrementFloatingButton);
+      expect(await _driver!.getText(counterState), '2');
     });
   });
 }