Implement switch expressions in dev/ (#139048)

I previously made a PR (#136140) that used `switch` expressions to make some parts of the Flutter codebase easier to understand. It was assigned to the framework team, and @christopherfujino let me know that it was too large to effectively review and recommended breaking it up into smaller pull requests.

Here's a PR that only targets files in the `dev/` directory. Hopefully this will be easier to work with!

(solves issue https://github.com/flutter/flutter/issues/136139)

dev/benchmarks/complex_layout/test/measure_scroll_smoothness.dart

@@ -68,40 +68,28 @@ class ResampleFlagVariant extends TestVariant<TestScenario> {
 
   late TestScenario currentValue;
   bool get resample {
-    switch (currentValue) {
-      case TestScenario.resampleOn90Hz:
-      case TestScenario.resampleOn59Hz:
-        return true;
-      case TestScenario.resampleOff90Hz:
-      case TestScenario.resampleOff59Hz:
-        return false;
-    }
+    return switch (currentValue) {
+      TestScenario.resampleOn90Hz  || TestScenario.resampleOn59Hz  => true,
+      TestScenario.resampleOff90Hz || TestScenario.resampleOff59Hz => false,
+    };
   }
   double get frequency {
-    switch (currentValue) {
-      case TestScenario.resampleOn90Hz:
-      case TestScenario.resampleOff90Hz:
-        return 90.0;
-      case TestScenario.resampleOn59Hz:
-      case TestScenario.resampleOff59Hz:
-        return 59.0;
-    }
+    return switch (currentValue) {
+      TestScenario.resampleOn90Hz || TestScenario.resampleOff90Hz => 90.0,
+      TestScenario.resampleOn59Hz || TestScenario.resampleOff59Hz => 59.0,
+    };
   }
 
   Map<String, dynamic>? result;
 
   @override
   String describeValue(TestScenario value) {
-    switch (value) {
-      case TestScenario.resampleOn90Hz:
-        return 'resample on with 90Hz input';
-      case TestScenario.resampleOn59Hz:
-        return 'resample on with 59Hz input';
-      case TestScenario.resampleOff90Hz:
-        return 'resample off with 90Hz input';
-      case TestScenario.resampleOff59Hz:
-        return 'resample off with 59Hz input';
-    }
+    return switch (value) {
+      TestScenario.resampleOn90Hz  => 'resample on with 90Hz input',
+      TestScenario.resampleOn59Hz  => 'resample on with 59Hz input',
+      TestScenario.resampleOff90Hz => 'resample off with 90Hz input',
+      TestScenario.resampleOff59Hz => 'resample off with 59Hz input',
+    };
   }
 
   @override

dev/benchmarks/macrobenchmarks/lib/src/filtered_child_animation.dart

@@ -60,12 +60,12 @@ class _FilteredChildAnimationPageState extends State<FilteredChildAnimationPage>
   }
 
   String get _title {
-    switch (_filterType) {
-      case FilterType.opacity: return 'Fading Child Animation';
-      case FilterType.rotateTransform: return 'Transformed Child Animation';
-      case FilterType.rotateFilter: return 'Matrix Filtered Child Animation';
-      case null: return 'Static Child';
-    }
+    return switch (_filterType) {
+      FilterType.opacity => 'Fading Child Animation',
+      FilterType.rotateTransform => 'Transformed Child Animation',
+      FilterType.rotateFilter => 'Matrix Filtered Child Animation',
+      null => 'Static Child',
+    };
   }
 
   static Widget _makeChild(int rows, int cols, double fontSize, bool complex) {

dev/bots/service_worker_test.dart

@@ -109,28 +109,17 @@ Future<void> _setAppVersion(int version) async {
 }
 
 String _testTypeToIndexFile(ServiceWorkerTestType type) {
-  late String indexFile;
-  switch (type) {
-    case ServiceWorkerTestType.blockedServiceWorkers:
-      indexFile = 'index_with_blocked_service_workers.html';
-    case ServiceWorkerTestType.withFlutterJs:
-      indexFile = 'index_with_flutterjs.html';
-    case ServiceWorkerTestType.withoutFlutterJs:
-      indexFile = 'index_without_flutterjs.html';
-    case ServiceWorkerTestType.withFlutterJsShort:
-      indexFile = 'index_with_flutterjs_short.html';
-    case ServiceWorkerTestType.withFlutterJsEntrypointLoadedEvent:
-      indexFile = 'index_with_flutterjs_entrypoint_loaded.html';
-    case ServiceWorkerTestType.withFlutterJsTrustedTypesOn:
-      indexFile = 'index_with_flutterjs_el_tt_on.html';
-    case ServiceWorkerTestType.withFlutterJsNonceOn:
-      indexFile = 'index_with_flutterjs_el_nonce.html';
-    case ServiceWorkerTestType.withFlutterJsCustomServiceWorkerVersion:
-      indexFile = 'index_with_flutterjs_custom_sw_version.html';
-    case ServiceWorkerTestType.generatedEntrypoint:
-      indexFile = 'generated_entrypoint.html';
-  }
-  return indexFile;
+  return switch (type) {
+    ServiceWorkerTestType.blockedServiceWorkers                   => 'index_with_blocked_service_workers.html',
+    ServiceWorkerTestType.withFlutterJs                           => 'index_with_flutterjs.html',
+    ServiceWorkerTestType.withoutFlutterJs                        => 'index_without_flutterjs.html',
+    ServiceWorkerTestType.withFlutterJsShort                      => 'index_with_flutterjs_short.html',
+    ServiceWorkerTestType.withFlutterJsEntrypointLoadedEvent      => 'index_with_flutterjs_entrypoint_loaded.html',
+    ServiceWorkerTestType.withFlutterJsTrustedTypesOn             => 'index_with_flutterjs_el_tt_on.html',
+    ServiceWorkerTestType.withFlutterJsNonceOn                    => 'index_with_flutterjs_el_nonce.html',
+    ServiceWorkerTestType.withFlutterJsCustomServiceWorkerVersion => 'index_with_flutterjs_custom_sw_version.html',
+    ServiceWorkerTestType.generatedEntrypoint                     => 'generated_entrypoint.html',
+  };
 }
 
 Future<void> _rebuildApp({ required int version, required ServiceWorkerTestType testType, required String target }) async {

dev/bots/unpublish_package.dart

@@ -49,53 +49,39 @@ class UnpublishException implements Exception {
 enum Channel { dev, beta, stable }
 
 String getChannelName(Channel channel) {
-  switch (channel) {
-    case Channel.beta:
-      return 'beta';
-    case Channel.dev:
-      return 'dev';
-    case Channel.stable:
-      return 'stable';
-  }
+  return switch (channel) {
+    Channel.beta   => 'beta',
+    Channel.dev    => 'dev',
+    Channel.stable => 'stable',
+  };
 }
 
 Channel fromChannelName(String? name) {
-  switch (name) {
-    case 'beta':
-      return Channel.beta;
-    case 'dev':
-      return Channel.dev;
-    case 'stable':
-      return Channel.stable;
-    default:
-      throw ArgumentError('Invalid channel name.');
-  }
+  return switch (name) {
+    'beta'   => Channel.beta,
+    'dev'    => Channel.dev,
+    'stable' => Channel.stable,
+    _ => throw ArgumentError('Invalid channel name.'),
+  };
 }
 
 enum PublishedPlatform { linux, macos, windows }
 
 String getPublishedPlatform(PublishedPlatform platform) {
-  switch (platform) {
-    case PublishedPlatform.linux:
-      return 'linux';
-    case PublishedPlatform.macos:
-      return 'macos';
-    case PublishedPlatform.windows:
-      return 'windows';
-  }
+  return switch (platform) {
+    PublishedPlatform.linux   => 'linux',
+    PublishedPlatform.macos   => 'macos',
+    PublishedPlatform.windows => 'windows',
+  };
 }
 
 PublishedPlatform fromPublishedPlatform(String name) {
-  switch (name) {
-    case 'linux':
-      return PublishedPlatform.linux;
-    case 'macos':
-      return PublishedPlatform.macos;
-    case 'windows':
-      return PublishedPlatform.windows;
-    default:
-      throw ArgumentError('Invalid published platform name.');
-  }
+  return switch (name) {
+    'linux'   => PublishedPlatform.linux,
+    'macos'   => PublishedPlatform.macos,
+    'windows' => PublishedPlatform.windows,
+    _ => throw ArgumentError('Invalid published platform name.'),
+  };
 }
 
 /// A helper class for classes that want to run a process, optionally have the

dev/conductor/core/lib/src/repository.dart

@@ -47,12 +47,10 @@ class Remote {
 
   /// The name of the remote.
   String get name {
-    switch (_name) {
-      case RemoteName.upstream:
-        return 'upstream';
-      case RemoteName.mirror:
-        return 'mirror';
-    }
+    return switch (_name) {
+      RemoteName.upstream => 'upstream',
+      RemoteName.mirror   => 'mirror',
+    };
   }
 
   /// The URL of the remote.

dev/conductor/core/lib/src/version.dart

@@ -295,15 +295,11 @@ class Version {
 
   @override
   String toString() {
-    switch (type) {
-      case VersionType.stable:
-        return '$x.$y.$z';
-      case VersionType.development:
-        return '$x.$y.$z-$m.$n.pre';
-      case VersionType.latest:
-        return '$x.$y.$z-$m.$n.pre.$commits';
-      case VersionType.gitDescribe:
-        return '$x.$y.$z-$m.$n.pre.$commits';
-    }
+    return switch (type) {
+      VersionType.stable      => '$x.$y.$z',
+      VersionType.development => '$x.$y.$z-$m.$n.pre',
+      VersionType.latest      => '$x.$y.$z-$m.$n.pre.$commits',
+      VersionType.gitDescribe => '$x.$y.$z-$m.$n.pre.$commits',
+    };
   }
 }

dev/devicelab/lib/tasks/perf_tests.dart

@@ -2089,14 +2089,11 @@ enum ReportedDurationTestFlavor {
 }
 
 String _reportedDurationTestToString(ReportedDurationTestFlavor flavor) {
-  switch (flavor) {
-    case ReportedDurationTestFlavor.debug:
-      return 'debug';
-    case ReportedDurationTestFlavor.profile:
-      return 'profile';
-    case ReportedDurationTestFlavor.release:
-      return 'release';
-  }
+  return switch (flavor) {
+    ReportedDurationTestFlavor.debug   => 'debug',
+    ReportedDurationTestFlavor.profile => 'profile',
+    ReportedDurationTestFlavor.release => 'release',
+  };
 }
 
 class ReportedDurationTest {

dev/integration_tests/channels/lib/src/basic_messaging.dart

@@ -32,13 +32,11 @@ class ExtendedStandardMessageCodec extends StandardMessageCodec {
 
   @override
   dynamic readValueOfType(int type, ReadBuffer buffer) {
-    switch (type) {
-    case _dateTime:
-      return DateTime.fromMillisecondsSinceEpoch(buffer.getInt64());
-    case _pair:
-      return Pair(readValue(buffer), readValue(buffer));
-    default: return super.readValueOfType(type, buffer);
-    }
+    return switch (type) {
+      _dateTime => DateTime.fromMillisecondsSinceEpoch(buffer.getInt64()),
+      _pair => Pair(readValue(buffer), readValue(buffer)),
+      _ => super.readValueOfType(type, buffer),
+    };
   }
 }
 

dev/integration_tests/flutter_gallery/lib/demo/calculator/logic.dart

@@ -75,16 +75,12 @@ class OperationToken extends ExpressionToken {
   Operation operation;
 
   static String? opString(Operation operation) {
-    switch (operation) {
-      case Operation.Addition:
-        return ' + ';
-      case Operation.Subtraction:
-        return ' - ';
-      case Operation.Multiplication:
-        return '  \u00D7  ';
-      case Operation.Division:
-        return '  \u00F7  ';
-    }
+    return switch (operation) {
+      Operation.Addition       => ' + ',
+      Operation.Subtraction    => ' - ',
+      Operation.Multiplication => '  \u00D7  ',
+      Operation.Division       => '  \u00F7  ',
+    };
   }
 }
 

dev/integration_tests/flutter_gallery/lib/demo/material/scrollable_tabs_demo.dart

@@ -163,14 +163,11 @@ class ScrollableTabsDemoState extends State<ScrollableTabsDemo> with SingleTicke
           isScrollable: true,
           indicator: getIndicator(),
           tabs: _allPages.map<Tab>((_Page page) {
-            switch (_demoStyle) {
-              case TabsDemoStyle.iconsAndText:
-                return Tab(text: page.text, icon: Icon(page.icon));
-              case TabsDemoStyle.iconsOnly:
-                return Tab(icon: Icon(page.icon));
-              case TabsDemoStyle.textOnly:
-                return Tab(text: page.text);
-            }
+            return switch (_demoStyle) {
+              TabsDemoStyle.iconsAndText => Tab(text: page.text, icon: Icon(page.icon)),
+              TabsDemoStyle.iconsOnly    => Tab(icon: Icon(page.icon)),
+              TabsDemoStyle.textOnly     => Tab(text: page.text),
+            };
           }).toList()
         ),
       ),

dev/integration_tests/flutter_gallery/lib/demo/shrine/expanding_bottom_sheet.dart

@@ -221,18 +221,13 @@ class ExpandingBottomSheetState extends State<ExpandingBottomSheet> with TickerP
   // Returns the correct width of the ExpandingBottomSheet based on the number of
   // products in the cart.
   double _widthFor(int numProducts) {
-    switch (numProducts) {
-      case 0:
-        return _kWidthForCartIcon;
-      case 1:
-        return 136.0;
-      case 2:
-        return 192.0;
-      case 3:
-        return 248.0;
-      default:
-        return 278.0;
-    }
+    return switch (numProducts) {
+      0 => _kWidthForCartIcon,
+      1 => 136.0,
+      2 => 192.0,
+      3 => 248.0,
+      _ => 278.0,
+    };
   }
 
   // Returns true if the cart is open or opening and false otherwise.

dev/integration_tests/flutter_gallery/lib/gallery/options.dart

@@ -411,20 +411,14 @@ class _PlatformItem extends StatelessWidget {
   final ValueChanged<GalleryOptions>? onOptionsChanged;
 
   String _platformLabel(TargetPlatform platform) {
-    switch (platform) {
-      case TargetPlatform.android:
-        return 'Mountain View';
-      case TargetPlatform.fuchsia:
-        return 'Fuchsia';
-      case TargetPlatform.iOS:
-        return 'Cupertino';
-      case TargetPlatform.linux:
-        return 'Material Desktop (linux)';
-      case TargetPlatform.macOS:
-        return 'Material Desktop (macOS)';
-      case TargetPlatform.windows:
-        return 'Material Desktop (Windows)';
-    }
+    return switch (platform) {
+      TargetPlatform.android => 'Mountain View',
+      TargetPlatform.fuchsia => 'Fuchsia',
+      TargetPlatform.iOS     => 'Cupertino',
+      TargetPlatform.linux   => 'Material Desktop (linux)',
+      TargetPlatform.macOS   => 'Material Desktop (macOS)',
+      TargetPlatform.windows => 'Material Desktop (Windows)',
+    };
   }
 
   @override

dev/manual_tests/lib/density.dart

@@ -174,17 +174,12 @@ class _OptionsState extends State<Options> {
   }
 
   VisualDensity _profileToDensity(String? profile) {
-    switch (profile) {
-      case 'standard':
-        return VisualDensity.standard;
-      case 'comfortable':
-        return VisualDensity.comfortable;
-      case 'compact':
-        return VisualDensity.compact;
-      case 'custom':
-      default:
-        return widget.model.density;
-    }
+    return switch (profile) {
+      'standard'    => VisualDensity.standard,
+      'comfortable' => VisualDensity.comfortable,
+      'compact'     => VisualDensity.compact,
+      'custom' || _ => widget.model.density,
+    };
   }
 
   @override

dev/manual_tests/lib/menu_anchor.dart

@@ -478,14 +478,11 @@ class _TestMenusState extends State<_TestMenus> {
   void _setCheck(TestMenu item) {
     debugPrint('App: Set Checkbox item ${item.label}');
     setState(() {
-      switch (checkboxState) {
-        case false:
-          checkboxState = true;
-        case true:
-          checkboxState = null;
-        case null:
-          checkboxState = false;
-      }
+      checkboxState = switch (checkboxState) {
+        false => true,
+        true  => null,
+        null  => false,
+      };
     });
   }
 

dev/tools/vitool/lib/vitool.dart

@@ -152,19 +152,13 @@ class PathCommandAnimation {
   }
 
   String toDart() {
-    String dartCommandClass;
-    switch (type) {
-      case 'M':
-        dartCommandClass = '_PathMoveTo';
-      case 'C':
-        dartCommandClass = '_PathCubicTo';
-      case 'L':
-        dartCommandClass = '_PathLineTo';
-      case 'Z':
-        dartCommandClass = '_PathClose';
-      default:
-        throw Exception('unsupported path command: $type');
-    }
+    final String dartCommandClass = switch (type) {
+      'M' => '_PathMoveTo',
+      'C' => '_PathCubicTo',
+      'L' => '_PathLineTo',
+      'Z' => '_PathClose',
+      _ => throw Exception('unsupported path command: $type'),
+    };
     final StringBuffer sb = StringBuffer();
     sb.write('${kIndent * 4}const $dartCommandClass(\n');
     for (final List<Point<double>> pointFrames in points) {