Add macOS to TargetPlatform (#43457)

This PR adds TargetPlatform.macOS to the TargetPlatform enum. This allows us to begin implementation of some adaptive UI based on which target platform is desired.

I haven't updated the tests here, that will come in a follow-up PR.

dev/manual_tests/lib/actions.dart

@@ -8,13 +8,17 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(const MaterialApp(
     title: 'Actions Demo',
     home: FocusDemo(),

dev/manual_tests/lib/animated_icons.dart

@@ -108,11 +108,16 @@ class IconSample {
   final String description;
 }
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
+
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(AnimatedIconsTestApp());
 }

dev/manual_tests/lib/drag_and_drop.dart

@@ -296,13 +296,17 @@ class DragAndDropAppState extends State<DragAndDropApp> {
   }
 }
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(MaterialApp(
     title: 'Drag and Drop Flutter Demo',
     home: DragAndDropApp(),

dev/manual_tests/lib/focus.dart

@@ -8,13 +8,17 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(const MaterialApp(
     title: 'Focus Demo',
     home: FocusDemo(),

dev/manual_tests/lib/hover.dart

@@ -8,13 +8,17 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(const MaterialApp(
     title: 'Hover Demo',
     home: HoverDemo(),

dev/manual_tests/lib/main.dart

@@ -7,13 +7,17 @@ import 'dart:io';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(const Directionality(
     textDirection: TextDirection.ltr,
     child: Center(

dev/manual_tests/lib/material_arc.dart

@@ -475,13 +475,17 @@ class _AnimationDemoState extends State<AnimationDemo> with TickerProviderStateM
   }
 }
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(const MaterialApp(
     home: AnimationDemo(),
   ));

dev/manual_tests/lib/overlay_geometry.dart

@@ -206,13 +206,17 @@ class OverlayGeometryAppState extends State<OverlayGeometryApp> {
   }
 }
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(MaterialApp(
     theme: ThemeData(
       brightness: Brightness.light,

dev/manual_tests/lib/page_view.dart

@@ -141,12 +141,17 @@ class PageViewAppState extends State<PageViewApp> {
   }
 }
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
+
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(MaterialApp(
     title: 'PageView',
     theme: ThemeData(

dev/manual_tests/lib/raw_keyboard.dart

@@ -8,13 +8,17 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(MaterialApp(
     title: 'Hardware Key Demo',
     home: Scaffold(

dev/manual_tests/lib/text.dart

@@ -12,13 +12,17 @@ import 'package:flutter/scheduler.dart';
 
 int seed = 0;
 
-void main() {
+// Sets a platform override for desktop to avoid exceptions. See
-  if (!kIsWeb && Platform.isMacOS) {
+// https://flutter.dev/desktop#target-platform-override for more info.
-    // TODO(gspencergoog): Update this when TargetPlatform includes macOS. https://github.com/flutter/flutter/issues/31366
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
-    // See https://github.com/flutter/flutter/wiki/Desktop-shells#target-platform-override
+void _enablePlatformOverrideForDesktop() {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
+}
 
+void main() {
+  _enablePlatformOverrideForDesktop();
   runApp(MaterialApp(
     title: 'Text tester',
     home: const Home(),

examples/flutter_gallery/lib/demo/material/drawer_demo.dart

@@ -64,6 +64,7 @@ class _DrawerDemoState extends State<DrawerDemo> with TickerProviderStateMixin {
       case TargetPlatform.fuchsia:
         return Icons.arrow_back;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return Icons.arrow_back_ios;
     }
     assert(false);

examples/flutter_gallery/lib/gallery/options.dart

@@ -360,6 +360,8 @@ class _PlatformItem extends StatelessWidget {
         return 'Fuchsia';
       case TargetPlatform.iOS:
         return 'Cupertino';
+      case TargetPlatform.macOS:
+        return 'Material Desktop (macOS)';
     }
     assert(false);
     return null;

examples/flutter_gallery/lib/main.dart

@@ -14,8 +14,12 @@ import 'gallery/app.dart';
 
 // Sets a platform override for desktop to avoid exceptions. See
 // https://flutter.dev/desktop#target-platform-override for more info.
+// TODO(gspencergoog): Remove once TargetPlatform includes all desktop platforms.
+// This is only included in the Gallery because Flutter's testing infrastructure
+// uses the Gallery for various tests, and this allows us to test on desktop
+// platforms that aren't yet supported in TargetPlatform.
 void _enablePlatformOverrideForDesktop() {
-  if (!kIsWeb && (Platform.isMacOS || Platform.isWindows || Platform.isLinux)) {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
 }

packages/flutter/lib/src/cupertino/picker.dart

@@ -230,6 +230,7 @@ class _CupertinoPickerState extends State<CupertinoPicker> {
         break;
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:
+      case TargetPlatform.macOS:
         hasSuitableHapticHardware = false;
         break;
     }

packages/flutter/lib/src/cupertino/switch.dart

@@ -445,8 +445,9 @@ class _RenderCupertinoSwitch extends RenderConstrainedBox {
       case TargetPlatform.iOS:
         HapticFeedback.lightImpact();
         break;
-      case TargetPlatform.fuchsia:
       case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.macOS:
         break;
     }
   }

packages/flutter/lib/src/foundation/_platform_io.dart

@@ -11,6 +11,8 @@ platform.TargetPlatform get defaultTargetPlatform {
   platform.TargetPlatform result;
   if (Platform.isIOS) {
     result = platform.TargetPlatform.iOS;
+  } else if (Platform.isMacOS) {
+    result = platform.TargetPlatform.macOS;
   } else if (Platform.isAndroid) {
     result = platform.TargetPlatform.android;
   } else if (Platform.isFuchsia) {

packages/flutter/lib/src/foundation/binding.dart

@@ -163,6 +163,9 @@ abstract class BindingBase {
               case 'iOS':
                 debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
                 break;
+              case 'macOS':
+                debugDefaultTargetPlatformOverride = TargetPlatform.macOS;
+                break;
               case 'fuchsia':
                 debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
                 break;

packages/flutter/lib/src/foundation/platform.dart

@@ -47,6 +47,9 @@ enum TargetPlatform {
 
   /// iOS: <http://www.apple.com/ios/>
   iOS,
+
+  /// macOS: <http://www.apple.com/macos>
+  macOS,
 }
 
 /// Override the [defaultTargetPlatform].

packages/flutter/lib/src/material/app.dart

@@ -481,6 +481,7 @@ class _MaterialScrollBehavior extends ScrollBehavior {
     // the base class as well.
     switch (getPlatform(context)) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return child;
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:

packages/flutter/lib/src/material/app_bar.dart

@@ -393,6 +393,7 @@ class AppBar extends StatefulWidget implements PreferredSizeWidget {
       case TargetPlatform.fuchsia:
         return false;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return actions == null || actions.length < 2;
     }
     return null;
@@ -483,6 +484,7 @@ class _AppBarState extends State<AppBar> {
           namesRoute = true;
           break;
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           break;
       }
       title = DefaultTextStyle(

packages/flutter/lib/src/material/back_button.dart

@@ -34,6 +34,7 @@ class BackButtonIcon extends StatelessWidget {
       case TargetPlatform.fuchsia:
         return Icons.arrow_back;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return Icons.arrow_back_ios;
     }
     assert(false);

packages/flutter/lib/src/material/bottom_sheet.dart

@@ -283,6 +283,7 @@ class _ModalBottomSheetState<T> extends State<_ModalBottomSheet<T>> {
   String _getRouteLabel(MaterialLocalizations localizations) {
     switch (Theme.of(context).platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return '';
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:

packages/flutter/lib/src/material/date_picker.dart

@@ -911,6 +911,7 @@ class _DatePickerDialogState extends State<_DatePickerDialog> {
         HapticFeedback.vibrate();
         break;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         break;
     }
   }

packages/flutter/lib/src/material/dialog.dart

@@ -314,6 +314,7 @@ class AlertDialog extends StatelessWidget {
     if (title == null) {
       switch (theme.platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           label = semanticLabel;
           break;
         case TargetPlatform.android:
@@ -591,6 +592,7 @@ class SimpleDialog extends StatelessWidget {
     String label = semanticLabel;
     if (title == null) {
       switch (theme.platform) {
+        case TargetPlatform.macOS:
         case TargetPlatform.iOS:
           label = semanticLabel;
           break;

packages/flutter/lib/src/material/drawer.dart

@@ -177,6 +177,7 @@ class Drawer extends StatelessWidget {
     String label = semanticLabel;
     switch (Theme.of(context).platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         label = semanticLabel;
         break;
       case TargetPlatform.android:
@@ -523,6 +524,7 @@ class DrawerControllerState extends State<DrawerController> with SingleTickerPro
           platformHasBackButton = true;
           break;
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
         case TargetPlatform.fuchsia:
           platformHasBackButton = false;
           break;

packages/flutter/lib/src/material/flexible_space_bar.dart

@@ -166,7 +166,7 @@ class FlexibleSpaceBar extends StatefulWidget {
   /// Whether the title should be centered.
   ///
   /// By default this property is true if the current target platform
-  /// is [TargetPlatform.iOS], false otherwise.
+  /// is [TargetPlatform.iOS] or [TargetPlatform.macOS], false otherwise.
   final bool centerTitle;
 
   /// Collapse effect while scrolling.
@@ -239,6 +239,7 @@ class _FlexibleSpaceBarState extends State<FlexibleSpaceBar> {
       case TargetPlatform.fuchsia:
         return false;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return true;
     }
     return null;
@@ -341,6 +342,7 @@ class _FlexibleSpaceBarState extends State<FlexibleSpaceBar> {
           Widget title;
           switch (theme.platform) {
             case TargetPlatform.iOS:
+            case TargetPlatform.macOS:
               title = widget.title;
               break;
             case TargetPlatform.fuchsia:
@@ -349,6 +351,7 @@ class _FlexibleSpaceBarState extends State<FlexibleSpaceBar> {
                 namesRoute: true,
                 child: widget.title,
               );
+              break;
           }
 
           // StretchMode.fadeTitle

packages/flutter/lib/src/material/page_transitions_theme.dart

@@ -486,14 +486,15 @@ class CupertinoPageTransitionsBuilder extends PageTransitionsBuilder {
 class PageTransitionsTheme extends Diagnosticable {
   /// Construct a PageTransitionsTheme.
   ///
-  /// By default the list of builders is: [FadeUpwardsPageTransitionsBuilder],
+  /// By default the list of builders is: [FadeUpwardsPageTransitionsBuilder]
-  /// [CupertinoPageTransitionsBuilder] for [TargetPlatform.android]
+  /// for [TargetPlatform.android], and [CupertinoPageTransitionsBuilder] for
-  /// and [TargetPlatform.iOS] respectively.
+  /// [TargetPlatform.iOS] and [TargetPlatform.macOS].
   const PageTransitionsTheme({ Map<TargetPlatform, PageTransitionsBuilder> builders }) : _builders = builders;
 
   static const Map<TargetPlatform, PageTransitionsBuilder> _defaultBuilders = <TargetPlatform, PageTransitionsBuilder>{
     TargetPlatform.android: FadeUpwardsPageTransitionsBuilder(),
     TargetPlatform.iOS: CupertinoPageTransitionsBuilder(),
+    TargetPlatform.macOS: CupertinoPageTransitionsBuilder(),
   };
 
   /// The [PageTransitionsBuilder]s supported by this theme.

packages/flutter/lib/src/material/popup_menu.dart

@@ -830,6 +830,7 @@ Future<T> showMenu<T>({
   String label = semanticLabel;
   switch (Theme.of(context).platform) {
     case TargetPlatform.iOS:
+    case TargetPlatform.macOS:
       label = semanticLabel;
       break;
     case TargetPlatform.android:
@@ -1083,6 +1084,7 @@ class _PopupMenuButtonState<T> extends State<PopupMenuButton<T>> {
       case TargetPlatform.fuchsia:
         return const Icon(Icons.more_vert);
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return const Icon(Icons.more_horiz);
     }
     return null;

packages/flutter/lib/src/material/scaffold.dart

@@ -2299,6 +2299,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin {
 
     switch (themeData.platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         _addIfNonNull(
           children,
           GestureDetector(

packages/flutter/lib/src/material/scrollbar.dart

@@ -86,6 +86,7 @@ class _ScrollbarState extends State<Scrollbar> with TickerProviderStateMixin {
     final ThemeData theme = Theme.of(context);
     switch (theme.platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         // On iOS, stop all local animations. CupertinoScrollbar has its own
         // animations.
         _fadeoutTimer?.cancel();

packages/flutter/lib/src/material/search.dart

@@ -487,6 +487,7 @@ class _SearchPageState<T> extends State<_SearchPage<T>> {
     String routeName;
     switch (theme.platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         routeName = '';
         break;
       case TargetPlatform.android:

packages/flutter/lib/src/material/selectable_text.dart

@@ -70,6 +70,7 @@ class _SelectableTextSelectionGestureDetectorBuilder extends TextSelectionGestur
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectPositionAt(
             from: details.globalPosition,
             cause: SelectionChangedCause.longPress,
@@ -93,6 +94,7 @@ class _SelectableTextSelectionGestureDetectorBuilder extends TextSelectionGestur
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectWordEdge(cause: SelectionChangedCause.tap);
           break;
         case TargetPlatform.android:
@@ -110,6 +112,7 @@ class _SelectableTextSelectionGestureDetectorBuilder extends TextSelectionGestur
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectPositionAt(
             from: details.globalPosition,
             cause: SelectionChangedCause.longPress,
@@ -462,6 +465,7 @@ class _SelectableTextState extends State<SelectableText> with AutomaticKeepAlive
 
     switch (Theme.of(context).platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         if (cause == SelectionChangedCause.longPress) {
           _editableText?.bringIntoView(selection.base);
         }
@@ -529,6 +533,7 @@ class _SelectableTextState extends State<SelectableText> with AutomaticKeepAlive
 
     switch (themeData.platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         forcePressEnabled = true;
         textSelectionControls = cupertinoTextSelectionControls;
         paintCursorAboveText = true;

packages/flutter/lib/src/material/slider.dart

@@ -502,6 +502,7 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
           case TargetPlatform.fuchsia:
             return _buildMaterialSlider(context);
           case TargetPlatform.iOS:
+          case TargetPlatform.macOS:
             return _buildCupertinoSlider(context);
         }
       }
@@ -888,14 +889,15 @@ class _RenderSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   double get _adjustmentUnit {
     switch (_platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
       // Matches iOS implementation of material slider.
         return 0.1;
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:
-      default:
       // Matches Android implementation of material slider.
         return 0.05;
     }
+    return 0.0;
   }
 
   void _updateLabelPainter() {

packages/flutter/lib/src/material/switch.dart

@@ -354,6 +354,7 @@ class _SwitchState extends State<Switch> with TickerProviderStateMixin {
           case TargetPlatform.fuchsia:
             return buildMaterialSwitch(context);
           case TargetPlatform.iOS:
+          case TargetPlatform.macOS:
             return buildCupertinoSwitch(context);
         }
       }

packages/flutter/lib/src/material/text_field.dart

@@ -59,6 +59,7 @@ class _TextFieldSelectionGestureDetectorBuilder extends TextSelectionGestureDete
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectPositionAt(
             from: details.globalPosition,
             cause: SelectionChangedCause.longPress,
@@ -82,6 +83,7 @@ class _TextFieldSelectionGestureDetectorBuilder extends TextSelectionGestureDete
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectWordEdge(cause: SelectionChangedCause.tap);
           break;
         case TargetPlatform.android:
@@ -100,6 +102,7 @@ class _TextFieldSelectionGestureDetectorBuilder extends TextSelectionGestureDete
     if (delegate.selectionEnabled) {
       switch (Theme.of(_state.context).platform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           renderEditable.selectPositionAt(
             from: details.globalPosition,
             cause: SelectionChangedCause.longPress,
@@ -868,6 +871,7 @@ class _TextFieldState extends State<TextField> implements TextSelectionGestureDe
 
     switch (Theme.of(context).platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         if (cause == SelectionChangedCause.longPress) {
           _editableText?.bringIntoView(selection.base);
         }
@@ -923,6 +927,7 @@ class _TextFieldState extends State<TextField> implements TextSelectionGestureDe
 
     switch (themeData.platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         forcePressEnabled = true;
         textSelectionControls = cupertinoTextSelectionControls;
         paintCursorAboveText = true;

packages/flutter/lib/src/material/theme_data.dart

@@ -873,9 +873,10 @@ class ThemeData extends Diagnosticable {
   /// In a test environment, the platform returned is [TargetPlatform.android]
   /// regardless of the host platform. (Android was chosen because the tests
   /// were originally written assuming Android-like behavior, and we added
-  /// platform adaptations for iOS later). Tests can check iOS behavior by
+  /// platform adaptations for other platforms later). Tests can check behavior
-  /// setting the [platform] of the [Theme] explicitly to [TargetPlatform.iOS],
+  /// for other platforms by setting the [platform] of the [Theme] explicitly to
-  /// or by setting [debugDefaultTargetPlatformOverride].
+  /// another [TargetPlatform] value, or by setting
+  /// [debugDefaultTargetPlatformOverride].
   final TargetPlatform platform;
 
   /// Configures the hit test size of certain Material widgets.

packages/flutter/lib/src/material/time_picker.dart

@@ -209,6 +209,7 @@ class _DayPeriodControl extends StatelessWidget {
         _announceToAccessibility(context, MaterialLocalizations.of(context).anteMeridiemAbbreviation);
         break;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         break;
     }
     _togglePeriod();
@@ -224,6 +225,7 @@ class _DayPeriodControl extends StatelessWidget {
         _announceToAccessibility(context, MaterialLocalizations.of(context).postMeridiemAbbreviation);
         break;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         break;
     }
     _togglePeriod();
@@ -1525,6 +1527,7 @@ class _TimePickerDialogState extends State<_TimePickerDialog> {
         });
         break;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         break;
     }
   }

packages/flutter/lib/src/material/typography.dart

@@ -88,10 +88,11 @@ enum ScriptCategory {
 class Typography extends Diagnosticable {
   /// Creates a typography instance.
   ///
-  /// If [platform] is [TargetPlatform.iOS], the default values for [black] and
+  /// If [platform] is [TargetPlatform.iOS] or [TargetPlatform.macOS], the
-  /// [white] are [blackCupertino] and [whiteCupertino] respectively. Otherwise
+  /// default values for [black] and [white] are [blackCupertino] and
-  /// they are [blackMountainView] and [whiteMoutainView]. If [platform] is
+  /// [whiteCupertino] respectively. Otherwise they are [blackMountainView] and
-  /// null then both [black] and [white] must be specified.
+  /// [whiteMoutainView]. If [platform] is null then both [black] and [white]
+  /// must be specified.
   ///
   /// The default values for [englishLike], [dense], and [tall] are
   /// [englishLike2014], [dense2014], and [tall2014].
@@ -106,6 +107,7 @@ class Typography extends Diagnosticable {
     assert(platform != null || (black != null && white != null));
     switch (platform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         black ??= blackCupertino;
         white ??= whiteCupertino;
         break;

packages/flutter/lib/src/rendering/editable.dart

@@ -1719,6 +1719,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     assert(defaultTargetPlatform != null);
     switch (defaultTargetPlatform) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return Rect.fromLTWH(0.0, 0.0, cursorWidth, preferredLineHeight + 2);
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:
@@ -1777,6 +1778,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     if (caretHeight != null) {
       switch (defaultTargetPlatform) {
         case TargetPlatform.iOS:
+        case TargetPlatform.macOS:
           final double heightDiff = caretHeight - caretRect.height;
           // Center the caret vertically along the text.
           caretRect = Rect.fromLTWH(

packages/flutter/lib/src/rendering/view.dart

@@ -253,8 +253,9 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
       case TargetPlatform.android:
         lowerOverlayStyle = layer.find<SystemUiOverlayStyle>(bottom);
         break;
-      case TargetPlatform.iOS:
       case TargetPlatform.fuchsia:
+      case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         break;
     }
     // If there are no overlay styles in the UI don't bother updating.

packages/flutter/lib/src/widgets/modal_barrier.dart

@@ -82,6 +82,7 @@ class ModalBarrier extends StatelessWidget {
         platformSupportsDismissingBarrier = false;
         break;
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         platformSupportsDismissingBarrier = true;
         break;
     }

packages/flutter/lib/src/widgets/routes.dart

@@ -1217,9 +1217,10 @@ abstract class ModalRoute<T> extends TransitionRoute<T> with LocalHistoryRoute<T
 
   /// True if one or more [WillPopCallback] callbacks exist.
   ///
-  /// This method is used to disable the horizontal swipe pop gesture
+  /// This method is used to disable the horizontal swipe pop gesture supported
-  /// supported by [MaterialPageRoute] for [TargetPlatform.iOS].
+  /// by [MaterialPageRoute] for [TargetPlatform.iOS] and
-  /// If a pop might be vetoed, then the back gesture is disabled.
+  /// [TargetPlatform.macOS]. If a pop might be vetoed, then the back gesture is
+  /// disabled.
   ///
   /// The [buildTransitions] method will not be called again if this changes,
   /// since it can change during the build as descendants of the route add or

packages/flutter/lib/src/widgets/scroll_configuration.dart

@@ -35,6 +35,7 @@ class ScrollBehavior {
     // _MaterialScrollBehavior as well.
     switch (getPlatform(context)) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return child;
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:
@@ -54,6 +55,7 @@ class ScrollBehavior {
   ScrollPhysics getScrollPhysics(BuildContext context) {
     switch (getPlatform(context)) {
       case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
         return const BouncingScrollPhysics();
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:

packages/flutter/test/widgets/sliver_fill_remaining_test.dart

@@ -331,6 +331,7 @@ void main() {
       final Finder button = find.byType(RaisedButton);
       expect(tester.getBottomLeft(button).dy, equals(550.0));
       expect(tester.getCenter(button).dx, equals(400.0));
+      debugDefaultTargetPlatformOverride = null;
 
       // Drag for overscroll
       await tester.drag(find.byType(Scrollable), const Offset(0.0, -50.0));

packages/flutter_tools/lib/src/commands/create.dart

@@ -656,7 +656,8 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
       // removed, and the new schema should always be used.
       'useNewPluginSchema': macos,
       // If a desktop platform is included, add a workaround for #31366.
-      'includeTargetPlatformWorkaround': macos,
+      // When Linux and Windows are added, we will need this workaround again.
+      'includeTargetPlatformWorkaround': false,
     };
   }
 

packages/flutter_tools/templates/app/lib/main.dart.tmpl

@@ -18,7 +18,7 @@ import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart';
 // Sets a platform override for desktop to avoid exceptions. See
 // https://flutter.dev/desktop#target-platform-override for more info.
 void _enablePlatformOverrideForDesktop() {
-  if (!kIsWeb && (Platform.isMacOS || Platform.isWindows || Platform.isLinux)) {
+  if (!kIsWeb && (Platform.isWindows || Platform.isLinux)) {
     debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
   }
 }