Adjust desktop feature flag (#74348)

Prep to make https://github.com/flutter/flutter/issues/73857 easier in the future.

packages/flutter_tools/lib/src/features.dart

@@ -159,9 +159,11 @@ const Feature flutterWebFeature = Feature(
 
 /// The [Feature] for macOS desktop.
 const Feature flutterMacOSDesktopFeature = Feature(
-  name: 'Flutter for desktop on macOS',
+  name: 'beta-quality support for desktop on macOS',
   configSetting: 'enable-macos-desktop',
   environmentOverride: 'FLUTTER_MACOS',
+  extraHelpText: flutterNext ?
+      'Newer beta versions are available on the beta channel.' : null,
   master: FeatureChannelSetting(
     available: true,
     enabledByDefault: false,
@@ -170,13 +172,23 @@ const Feature flutterMacOSDesktopFeature = Feature(
     available: true,
     enabledByDefault: false,
   ),
+  beta: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
+  stable: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
 );
 
 /// The [Feature] for Linux desktop.
 const Feature flutterLinuxDesktopFeature = Feature(
-  name: 'Flutter for desktop on Linux',
+  name: 'beta-quality support for desktop on Linux',
   configSetting: 'enable-linux-desktop',
   environmentOverride: 'FLUTTER_LINUX',
+  extraHelpText: flutterNext ?
+      'Newer beta versions are available on the beta channel.' : null,
   master: FeatureChannelSetting(
     available: true,
     enabledByDefault: false,
@@ -185,13 +197,23 @@ const Feature flutterLinuxDesktopFeature = Feature(
     available: true,
     enabledByDefault: false,
   ),
+  beta: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
+  stable: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
 );
 
 /// The [Feature] for Windows desktop.
 const Feature flutterWindowsDesktopFeature = Feature(
-  name: 'Flutter for desktop on Windows',
+  name: 'beta-quality support for desktop on Windows',
   configSetting: 'enable-windows-desktop',
   environmentOverride: 'FLUTTER_WINDOWS',
+  extraHelpText: flutterNext ?
+      'Newer beta versions are available on the beta channel.' : null,
   master: FeatureChannelSetting(
     available: true,
     enabledByDefault: false,
@@ -200,6 +222,14 @@ const Feature flutterWindowsDesktopFeature = Feature(
     available: true,
     enabledByDefault: false,
   ),
+  beta: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
+  stable: FeatureChannelSetting(
+    available: flutterNext,
+    enabledByDefault: false,
+  ),
 );
 
 /// The [Feature] for Android devices.
@@ -318,6 +348,7 @@ class Feature {
     @required this.name,
     this.environmentOverride,
     this.configSetting,
+    this.extraHelpText,
     this.master = const FeatureChannelSetting(),
     this.dev = const FeatureChannelSetting(),
     this.beta = const FeatureChannelSetting(),
@@ -353,6 +384,11 @@ class Feature {
   /// If not provided, defaults to `null` meaning there is no config setting.
   final String configSetting;
 
+  /// Additional text to add to the end of the help message.
+  ///
+  /// If not provided, defaults to `null` meaning there is no additional text.
+  final String extraHelpText;
+
   /// A help message for the `flutter config` command, or null if unsupported.
   String generateHelpMessage() {
     if (configSetting == null) {
@@ -375,6 +411,9 @@ class Feature {
         ..removeLast()).join(', ');
       buffer.write('the $prefix, and ${channels.last} channels.');
     }
+    if (extraHelpText != null) {
+      buffer.write(' $extraHelpText');
+    }
     return buffer.toString();
   }
 

packages/flutter_tools/test/general.shard/features_test.dart

@@ -84,19 +84,19 @@ void main() {
 
     testWithoutContext('flutter macOS desktop help string', () {
       expect(flutterMacOSDesktopFeature.generateHelpMessage(),
-      'Enable or disable Flutter for desktop on macOS. '
+      'Enable or disable beta-quality support for desktop on macOS. '
       'This setting will take effect on the master and dev channels.');
     });
 
     testWithoutContext('flutter Linux desktop help string', () {
       expect(flutterLinuxDesktopFeature.generateHelpMessage(),
-      'Enable or disable Flutter for desktop on Linux. '
+      'Enable or disable beta-quality support for desktop on Linux. '
       'This setting will take effect on the master and dev channels.');
     });
 
     testWithoutContext('flutter Windows desktop help string', () {
       expect(flutterWindowsDesktopFeature.generateHelpMessage(),
-      'Enable or disable Flutter for desktop on Windows. '
+      'Enable or disable beta-quality support for desktop on Windows. '
       'This setting will take effect on the master and dev channels.');
     });
 
@@ -244,9 +244,9 @@ void main() {
       expect(featureFlags.isMacOSEnabled, false);
     });
 
-    testWithoutContext('fflutter macos desktop not enabled with config on beta', () {
+    testWithoutContext('flutter macos desktop not enabled with config on beta', () {
       when(mockFlutterVerion.channel).thenReturn('beta');
-      when<bool>(mockFlutterConfig.getValue('flutter-desktop-macos') as bool).thenReturn(true);
+      when<bool>(mockFlutterConfig.getValue('enable-macos-desktop') as bool).thenReturn(true);
 
       expect(featureFlags.isMacOSEnabled, false);
     });
@@ -266,7 +266,7 @@ void main() {
 
     testWithoutContext('flutter macos desktop not enabled with config on stable', () {
       when(mockFlutterVerion.channel).thenReturn('stable');
-      when<bool>(mockFlutterConfig.getValue('flutter-desktop-macos') as bool).thenReturn(true);
+      when<bool>(mockFlutterConfig.getValue('enable-macos-desktop') as bool).thenReturn(true);
 
       expect(featureFlags.isMacOSEnabled, false);
     });
@@ -325,7 +325,7 @@ void main() {
       expect(featureFlags.isLinuxEnabled, false);
     });
 
-    testWithoutContext('fflutter linux desktop not enabled with config on beta', () {
+    testWithoutContext('flutter linux desktop not enabled with config on beta', () {
       when(mockFlutterVerion.channel).thenReturn('beta');
       when<bool>(mockFlutterConfig.getValue('enable-linux-desktop') as bool).thenReturn(true);
 
@@ -406,7 +406,7 @@ void main() {
       expect(featureFlags.isWindowsEnabled, false);
     });
 
-    testWithoutContext('fflutter windows desktop not enabled with config on beta', () {
+    testWithoutContext('flutter windows desktop not enabled with config on beta', () {
       when(mockFlutterVerion.channel).thenReturn('beta');
       when<bool>(mockFlutterConfig.getValue('enable-windows-desktop') as bool).thenReturn(true);