Upgrading samples to flutter_lints, part 1 of n (#804)

web/samples_index/analysis_options.yaml

@@ -1,14 +1,22 @@
-# Defines a default set of lint rules enforced for
-# projects at Google. For details and rationale,
-# see https://github.com/dart-lang/pedantic#enabled-lints.
-include: package:pedantic/analysis_options.yaml
-
-# For lint rules and documentation, see http://dart-lang.github.io/linter/lints.
-# Uncomment to specify additional rules.
-# linter:
-#   rules:
-#     - camel_case_types
+include: package:flutter_lints/flutter.yaml
 
 analyzer:
-#   exclude:
-#     - path/to/excluded/files/**
+  exclude:
+    - lib/src/data.g.dart
+  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
+    use_key_in_widget_constructors: false

web/samples_index/lib/cookbook.dart

@@ -15,7 +15,7 @@ class CookbookScraper {
   WebDriver _driver;
 
   Future init() async {
-    _driver = await createDriver(desired: {});
+    _driver = await createDriver(desired: <String, dynamic>{});
   }
 
   Future dispose() async {

web/samples_index/lib/samples_index.dart

@@ -4,9 +4,9 @@
 
 import 'dart:convert';
 import 'dart:io';
+import 'package:checked_yaml/checked_yaml.dart';
 
 import 'src/data.dart';
-import 'package:checked_yaml/checked_yaml.dart';
 
 export 'src/data.dart';
 
@@ -17,6 +17,7 @@ Future<List<Sample>> getSamples() async {
   var cookbookContents = await cookbookFile.readAsString();
   var index = checkedYamlDecode(contents, (m) => Index.fromJson(m),
       sourceUrl: yamlFile.uri);
-  var cookbookIndex = Index.fromJson(json.decode(cookbookContents));
+  var cookbookIndex =
+      Index.fromJson(json.decode(cookbookContents) as Map<dynamic, dynamic>);
   return index.samples..addAll(cookbookIndex.samples);
 }

web/samples_index/lib/src/carousel.dart

@@ -45,13 +45,14 @@ class Carousel {
 
     // Move to the first slide after init
     // This is responsible for creating a smooth animation
-    Future.delayed(Duration(milliseconds: 500)).then((value) => _slideRight());
+    Future<void>.delayed(const Duration(milliseconds: 500))
+        .then((value) => _slideRight());
   }
 
   void _hideSlides() {
-    slides.forEach((s) {
+    for (final s in slides) {
       s.classes.add('next-hidden');
-    });
+    }
   }
 
   void _initBullets() {
@@ -95,7 +96,7 @@ class Carousel {
 
   void _touchEndListener(TouchEvent e) {
     if (touched) {
-      int dx = e.changedTouches.first.client.x - x0;
+      int dx = (e.changedTouches.first.client.x - x0) as int;
 
       // dx==0 case is ignored
       if (dx > 0 && currentSlideIndex > 0) {
@@ -167,11 +168,11 @@ class Carousel {
       nextSlide = slides[0];
     }
 
-    slides.forEach((e) {
+    for (final e in slides) {
       _removeSlideClasses([e]);
       if (e.classes.contains('prev-hidden')) e.classes.add('next-hidden');
       if (e.classes.contains('prev')) e.classes.add('prev-hidden');
-    });
+    }
 
     _removeSlideClasses([prevSlide, currentSlide, nextSlide]);
 
@@ -203,11 +204,11 @@ class Carousel {
       prevSlide = slides[lastSlideIndex];
     }
 
-    slides.forEach((e) {
+    for (final e in slides) {
       _removeSlideClasses([e]);
       if (e.classes.contains('next')) e.classes.add('next-hidden');
       if (e.classes.contains('next-hidden')) e.classes.add('prev-hidden');
-    });
+    }
 
     _removeSlideClasses([prevSlide, currentSlide, nextSlide]);
 
@@ -218,7 +219,7 @@ class Carousel {
     _updateBullets();
   }
 
-  void _goToIndexSlide(index) {
+  void _goToIndexSlide(int index) {
     final sliding =
         (currentSlideIndex < index) ? () => _slideRight() : () => _slideLeft();
     while (currentSlideIndex != index) {
@@ -227,10 +228,10 @@ class Carousel {
   }
 
   void _removeSlideClasses(List<Element> slides) {
-    slides.forEach((s) {
+    for (final s in slides) {
       s.classes
           .removeAll(['prev-hidden', 'prev', 'active', 'next', 'next-hidden']);
-    });
+    }
   }
 
   void _initArrowKeyControl() {

web/samples_index/lib/src/templates.dart

@@ -7,9 +7,9 @@ import 'data.dart';
 import 'util.dart' as util;
 
 String _escapeAttribute(String s) =>
-    HtmlEscape(HtmlEscapeMode.attribute).convert(s);
+    const HtmlEscape(HtmlEscapeMode.attribute).convert(s);
 String _escapeElement(String s) =>
-    HtmlEscape(HtmlEscapeMode.element).convert(s);
+    const HtmlEscape(HtmlEscapeMode.element).convert(s);
 
 String description(Sample sample) => '''
 <!DOCTYPE html>

web/samples_index/pubspec.yaml

@@ -4,7 +4,7 @@ homepage: https://github.com/flutter/samples_index
 author: Flutter Team <flutter-dev@googlegroups.com>
 version: 0.0.1
 environment:
-  sdk: '>=2.5.0 <3.0.0'
+  sdk: ">=2.5.0 <3.0.0"
 dependencies:
   json_annotation: ^3.0.0
   path: ^1.6.0
@@ -16,7 +16,7 @@ dependencies:
   html: ^0.14.0
 dev_dependencies:
   grinder: ^0.8.3
-  pedantic: ^1.9.0
+  flutter_lints: ^1.0.0
   test: ^1.6.0
   json_serializable: ^3.2.0
   build: ^1.2.0

web/samples_index/test/samples_index_test.dart

@@ -54,7 +54,7 @@ void main() {
       var sample = index.samples.first;
       expect(
           sample.searchAttributes.split(' '),
-          containsAll([
+          containsAll(const <String>[
             'kittens',
             'tag:beginner',
             'tag:kittens',

web/samples_index/tool/grind.dart

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file
 
-import 'dart:io';
 import 'dart:convert';
+import 'dart:io';
 
 import 'package:grinder/grinder.dart';
 import 'package:path/path.dart' as path;
@@ -12,10 +12,11 @@ import 'package:samples_index/src/templates.dart' as templates;
 import 'package:samples_index/cookbook.dart';
 import 'package:image/image.dart' as image;
 
-void main(args) => grind(args);
+Future<void> main(List<String> args) => grind(args);
 
 @Task('Run tests in the VM')
-void testCli() async => await TestRunner().testAsync(platformSelector: 'vm');
+Future<void> testCli() async =>
+    await TestRunner().testAsync(platformSelector: 'vm');
 
 @Task()
 void analyze() {
@@ -25,13 +26,13 @@ void analyze() {
 @Task('deploy')
 @Depends(analyze, testCli, generate, buildRelease)
 void deploy() {
-  print('All tasks completed. ');
-  print('');
+  log('All tasks completed. ');
+  log('');
 }
 
 @Task('Run build_runner to public/ directory')
 @Depends(createThumbnails)
-Future buildRelease() async {
+Future<void> buildRelease() async {
   var app = PubApp.local('build_runner');
   await app.runAsync(
       'build --release --output web:public --delete-conflicting-outputs'
@@ -41,9 +42,9 @@ Future buildRelease() async {
 
 @DefaultTask('Build the project.')
 @Depends(clean)
-Future generate() async {
+Future<void> generate() async {
   var samples = await getSamples();
-  print('Generating index for ${samples.length} samples...');
+  log('Generating index for ${samples.length} samples...');
   var outputFile = File('web/index.html');
   await outputFile.create(recursive: true);
   await outputFile.writeAsString(templates.index(samples));
@@ -55,12 +56,12 @@ Future generate() async {
     });
     futures.add(future);
   }
-  await Future.wait(futures);
-  print('Generated index for ${samples.length} samples.');
+  await Future.wait<void>(futures);
+  log('Generated index for ${samples.length} samples.');
 }
 
 @Task('Scrape the cookbook for images and descriptions')
-Future scrapeCookbook() async {
+Future<void> scrapeCookbook() async {
   var driver = await Process.start(
       'chromedriver', ['--port=4444', '--url-base=wd/hub', '--verbose']);
   await driver.stdout.pipe(stdout);
@@ -68,7 +69,7 @@ Future scrapeCookbook() async {
   var scraper = CookbookScraper();
   await scraper.init();
   var links = await scraper.fetchCookbookLinks();
-  print('Scraping ${links.length} cookbook articles');
+  log('Scraping ${links.length} cookbook articles');
   var allSamples = <Sample>[];
   for (var link in links) {
     allSamples.add(await scraper.getMetadata(link));
@@ -76,23 +77,23 @@ Future scrapeCookbook() async {
   }
   var file = File('lib/src/cookbook.json');
   await file.create();
-  var encoder = JsonEncoder.withIndent('\t');
+  var encoder = const JsonEncoder.withIndent('\t');
   await file.writeAsString(encoder.convert(Index(allSamples)));
   await scraper.dispose();
   var killed = driver.kill();
   if (!killed) {
-    print('failed to kill chromedriver process');
+    log('failed to kill chromedriver process');
   }
 }
 
 @Task('creates thumbnail images in web/images')
-Future createThumbnails() async {
+Future<void> createThumbnails() async {
   await _createThumbnails(Directory('web/images'));
   await _createThumbnails(Directory('web/images/cookbook'));
 }
 
 // Creates a thumbnail image for each png file
-Future _createThumbnails(Directory directory) async {
+Future<void> _createThumbnails(Directory directory) async {
   var files = await directory.list().toList();
   var filesToWrite = <Future>{};
 
@@ -112,16 +113,16 @@ Future _createThumbnails(Directory directory) async {
     filesToWrite.add(thumbnailFile.writeAsBytes(image.encodePng(resized)));
   }
 
-  await Future.wait(filesToWrite);
+  await Future.wait<void>(filesToWrite);
 }
 
 @Task('remove generated HTML files')
-Future clean() async {
+Future<void> clean() async {
   var tasks = <Future>[];
   await for (var file in Directory('web').list(recursive: true)) {
     if (path.extension(file.path) == '.html') {
       tasks.add(file.delete());
     }
   }
-  await Future.wait(tasks);
+  await Future.wait<void>(tasks);
 }

web/samples_index/web/main.dart

@@ -37,13 +37,13 @@ void main() {
     }));
 
   // Filter cards on each keypress
-  searchBar.listen('keydown', (Event e) async {
+  searchBar.listen('keydown', (e) async {
     await Future(() {});
     handleSearch();
   });
 
   // Update the URL only when the user is done typing in the search bar
-  searchBar.listen('change', (Event e) {
+  searchBar.listen('change', (e) {
     queryParams[searchKey] = searchBar.value;
     updateHash();
   });
@@ -58,7 +58,7 @@ void main() {
 
   // Initialize chips
   chipSet = MDCChipSet(querySelector('.mdc-chip-set'));
-  chipSet.listen('MDCChip:selection', (Event e) {
+  chipSet.listen('MDCChip:selection', (e) {
     // Get the query parameters for this chip
     var selectedChipIndex = chipSet.chips.indexWhere((chip) => chip.selected);
     var chipParams = paramsForChip(selectedChipIndex);