Add flutter_lints to null_safety (#828)

null_safety/null_unsafe_app/analysis_options.yaml

@@ -0,0 +1,19 @@
+include: package:flutter_lints/flutter.yaml
+
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+
+linter:
+  rules:
+    avoid_types_on_closure_parameters: true
+    avoid_void_async: true
+    cancel_subscriptions: true
+    close_sinks: true
+    directives_ordering: true
+    package_api_docs: true
+    package_prefixed_library_names: true
+    test_types_in_equals: true
+    throw_in_finally: true
+    unnecessary_statements: true

null_safety/null_unsafe_app/lib/main.dart

@@ -5,13 +5,15 @@
 import 'package:flutter/material.dart';
 
 void main() {
-  runApp(MyApp());
+  runApp(const MyApp());
 }
 
 // This app simulates possible null errors. Try running it and see if it fails.
 // You can then try to hot reload a few times; you should see it occasionally
 // failing and occasionally succeeding.
 class MyApp extends StatelessWidget {
+  const MyApp({Key key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
     // Get data from services. Note: in a real application,
@@ -28,7 +30,7 @@ class MyApp extends StatelessWidget {
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.start,
             children: [
-              Text('Temperature next 3 days:'),
+              const Text('Temperature next 3 days:'),
               for (final t in temperatures) Text(t.round().toString()),
             ],
           ),

null_safety/null_unsafe_app/pubspec.lock

@@ -62,11 +62,25 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_lints:
+    dependency: "direct dev"
+    description:
+      name: flutter_lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.3"
   flutter_test:
     dependency: "direct dev"
     description: flutter
     source: sdk
     version: "0.0.0"
+  lints:
+    dependency: transitive
+    description:
+      name: lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   matcher:
     dependency: transitive
     description:

null_safety/null_unsafe_app/pubspec.yaml

@@ -1,6 +1,6 @@
 name: null_unsafe_app
 description: A new Flutter project.
-publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+publish_to: "none" # Remove this line if you wish to publish to pub.dev
 version: 1.0.0+1
 
 environment:
@@ -14,5 +14,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  flutter_lints: ^1.0.0
+
 flutter:
   uses-material-design: true

null_safety/null_unsafe_app/test/widget_test.dart

@@ -8,8 +8,7 @@
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  testWidgets('Rendering the page throws an exception',
-      (WidgetTester tester) async {
+  testWidgets('Rendering the page throws an exception', (tester) async {
     // Do nothing, running the app throws an exception on widget render.
   });
 }