[flutter_tools] describe current null safety build mode (#73426)

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

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:meta/meta.dart';
+
+import '../build_info.dart';
 import '../commands/build_linux.dart';
 import '../commands/build_macos.dart';
 import '../commands/build_windows.dart';
@@ -52,4 +55,25 @@ abstract class BuildSubCommand extends FlutterCommand {
 
   @override
   bool get reportNullSafety => true;
+
+  /// Display a message describing the current null safety runtime mode
+  /// that was selected.
+  ///
+  /// This is similar to the run message in run_hot.dart
+  @protected
+  void displayNullSafetyMode(BuildInfo buildInfo) {
+    globals.printStatus('');
+    if (buildInfo.nullSafetyMode ==  NullSafetyMode.sound) {
+      globals.printStatus('💪 Building with sound null safety 💪', emphasis: true);
+    } else {
+      globals.printStatus(
+        'Building with unsound null safety',
+        emphasis: true,
+      );
+      globals.printStatus(
+        'For more information see https://dart.dev/null-safety/unsound-null-safety',
+      );
+    }
+    globals.printStatus('');
+  }
 }

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

@@ -126,6 +126,7 @@ class BuildAarCommand extends BuildSubCommand {
       throwToolExit('Please specify a build mode and try again.');
     }
 
+    displayNullSafetyMode(androidBuildInfo.first.buildInfo);
     await androidBuilder.buildAar(
       project: _getProject(),
       target: '', // Not needed because this command only builds Android's code.

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

@@ -5,7 +5,6 @@
 import '../android/android_builder.dart';
 import '../android/build_validation.dart';
 import '../android/gradle_utils.dart';
-import '../base/terminal.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../globals.dart' as globals;
@@ -61,7 +60,10 @@ class BuildApkCommand extends BuildSubCommand {
   final String description = 'Build an Android APK file from your app.\n\n'
     "This command can build debug and release versions of your application. 'debug' builds support "
     "debugging and a quick development cycle. 'release' builds don't support debugging and are "
-    'suitable for deploying to app stores.';
+    'suitable for deploying to app stores. If you are deploying the app to the Play Store, '
+    'it\'s recommended to use app bundles or split the APK to reduce the APK size. Learn more at:\n\n'
+    ' * https://developer.android.com/guide/app-bundle\n'
+    ' * https://developer.android.com/studio/build/configure-apk-splits#configure-abi-split';
 
   @override
   Future<Map<CustomDimensions, String>> get usageValues async {
@@ -97,24 +99,7 @@ class BuildApkCommand extends BuildSubCommand {
       targetArchs: stringsArg('target-platform').map<AndroidArch>(getAndroidArchForName),
     );
     validateBuild(androidBuildInfo);
-
-    if (buildInfo.isRelease && !androidBuildInfo.splitPerAbi && androidBuildInfo.targetArchs.length > 1) {
-      final String targetPlatforms = stringsArg('target-platform').join(', ');
-
-      globals.printStatus('You are building a fat APK that includes binaries for '
-                  '$targetPlatforms.', emphasis: true, color: TerminalColor.green);
-      globals.printStatus('If you are deploying the app to the Play Store, '
-                  "it's recommended to use app bundles or split the APK to reduce the APK size.", emphasis: true);
-      globals.printStatus('To generate an app bundle, run:', emphasis: true, indent: 4);
-      globals.printStatus('flutter build appbundle '
-                  '--target-platform ${targetPlatforms.replaceAll(' ', '')}',indent: 8);
-      globals.printStatus('Learn more: https://developer.android.com/guide/app-bundle',indent: 8);
-      globals.printStatus('To split the APKs per ABI, run:', emphasis: true, indent: 4);
-      globals.printStatus('flutter build apk '
-                  '--target-platform ${targetPlatforms.replaceAll(' ', '')} '
-                  '--split-per-abi', indent: 8);
-      globals.printStatus('Learn more: https://developer.android.com/studio/build/configure-apk-splits#configure-abi-split',indent: 8);
-    }
+    displayNullSafetyMode(androidBuildInfo.buildInfo);
     await androidBuilder.buildApk(
       project: FlutterProject.current(),
       target: targetFile,

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

@@ -86,6 +86,7 @@ class BuildAppBundleCommand extends BuildSubCommand {
       targetArchs: stringsArg('target-platform').map<AndroidArch>(getAndroidArchForName),
     );
     validateBuild(androidBuildInfo);
+    displayNullSafetyMode(androidBuildInfo.buildInfo);
     await androidBuilder.buildAab(
       project: FlutterProject.current(),
       target: targetFile,

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

@@ -97,6 +97,7 @@ class BuildBundleCommand extends BuildSubCommand {
     }
 
     final BuildInfo buildInfo = await getBuildInfo();
+    displayNullSafetyMode(buildInfo);
 
     await bundleBuilder.build(
       platform: platform,

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

@@ -72,6 +72,7 @@ class BuildFuchsiaCommand extends BuildSubCommand {
     if (!flutterProject.fuchsia.existsSync()) {
       throwToolExit('No Fuchsia project is configured.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildFuchsia(
       fuchsiaProject: flutterProject.fuchsia,
       target: targetFile,

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

@@ -110,6 +110,7 @@ class BuildIOSArchiveCommand extends _BuildIOSSubCommand {
     }
     final FlutterCommandResult xcarchiveResult = await super.runCommand();
     final BuildInfo buildInfo = await getBuildInfo();
+    displayNullSafetyMode(buildInfo);
 
     if (exportOptionsPlist == null) {
       return xcarchiveResult;

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

@@ -127,7 +127,7 @@ class BuildIOSFrameworkCommand extends BuildSubCommand {
 
   FlutterProject _project;
 
-  Future<List<BuildInfo>> get buildInfos async {
+  Future<List<BuildInfo>> getBuildInfos() async {
     final List<BuildInfo> buildInfos = <BuildInfo>[];
 
     if (boolArg('debug')) {
@@ -154,7 +154,7 @@ class BuildIOSFrameworkCommand extends BuildSubCommand {
     if (boolArg('universal')) {
       throwToolExit('--universal has been deprecated, only XCFrameworks are supported.');
     }
-    if ((await buildInfos).isEmpty) {
+    if ((await getBuildInfos()).isEmpty) {
       throwToolExit('At least one of "--debug" or "--profile", or "--release" is required.');
     }
   }
@@ -173,8 +173,9 @@ class BuildIOSFrameworkCommand extends BuildSubCommand {
     }
 
     final Directory outputDirectory = globals.fs.directory(globals.fs.path.absolute(globals.fs.path.normalize(outputArgument)));
-
-    for (final BuildInfo buildInfo in await buildInfos) {
+    final List<BuildInfo> buildInfos = await getBuildInfos();
+    displayNullSafetyMode(buildInfos.first);
+    for (final BuildInfo buildInfo in buildInfos) {
       final String productBundleIdentifier = await _project.ios.productBundleIdentifier(buildInfo);
       globals.printStatus('Building frameworks for $productBundleIdentifier in ${getNameForBuildMode(buildInfo.mode)} mode...');
       final String xcodeBuildConfiguration = toTitleCase(getNameForBuildMode(buildInfo.mode));

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

@@ -43,6 +43,7 @@ class BuildLinuxCommand extends BuildSubCommand {
     if (!globals.platform.isLinux) {
       throwToolExit('"build linux" only supported on Linux hosts.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildLinux(
       flutterProject.linux,
       buildInfo,

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

@@ -47,6 +47,7 @@ class BuildMacosCommand extends BuildSubCommand {
     if (!globals.platform.isMacOS) {
       throwToolExit('"build macos" only supported on macOS hosts.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildMacOS(
       flutterProject: flutterProject,
       buildInfo: buildInfo,

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

@@ -84,6 +84,7 @@ class BuildWebCommand extends BuildSubCommand {
     if (buildInfo.isDebug) {
       throwToolExit('debug builds cannot be built directly for the web. Try using "flutter run"');
     }
+    displayNullSafetyMode(buildInfo);
     await buildWeb(
       flutterProject,
       target,

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

@@ -49,6 +49,7 @@ class BuildWindowsCommand extends BuildSubCommand {
     if (!globals.platform.isWindows) {
       throwToolExit('"build windows" only supported on Windows hosts.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildWindows(
       flutterProject.windows,
       buildInfo,

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -661,7 +661,8 @@ abstract class FlutterCommand extends Command<void> {
       FlutterOptions.kPerformanceMeasurementFile,
       help:
         'The name of a file where flutter assemble performance and '
-        'cached-ness information will be written in a JSON format.'
+        'cached-ness information will be written in a JSON format.',
+      hide: hide,
     );
   }
 
@@ -674,6 +675,7 @@ abstract class FlutterCommand extends Command<void> {
         "'--no-daemon' to the gradle wrapper script. This flag will cause the daemon "
         'process to terminate after the build is completed',
       defaultsTo: true,
+      hide: hide,
     );
   }
 

packages/flutter_tools/test/general.shard/commands/build_test.dart

@@ -3,7 +3,9 @@
 // found in the LICENSE file.
 
 import 'package:args/args.dart';
+import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/commands/attach.dart';
+import 'package:flutter_tools/src/commands/build.dart';
 import 'package:flutter_tools/src/commands/build_aar.dart';
 import 'package:flutter_tools/src/commands/build_apk.dart';
 import 'package:flutter_tools/src/commands/build_appbundle.dart';
@@ -47,4 +49,45 @@ void main() {
       expect(results.wasParsed('enable-experiment'), true);
     }
   });
+
+  testUsingContext('BuildSubCommand displays current null safety mode', () async {
+    const BuildInfo unsound = BuildInfo(
+      BuildMode.debug,
+      '',
+      trackWidgetCreation: false,
+      nullSafetyMode: NullSafetyMode.unsound,
+      treeShakeIcons: false,
+    );
+    const BuildInfo sound = BuildInfo(
+      BuildMode.debug,
+      '',
+      trackWidgetCreation: false,
+      nullSafetyMode: NullSafetyMode.sound,
+      treeShakeIcons: false,
+    );
+
+    FakeBuildSubCommand().test(unsound);
+    expect(testLogger.statusText, contains('Building with unsound null safety'));
+
+    testLogger.clear();
+    FakeBuildSubCommand().test(sound);
+    expect(testLogger.statusText, contains('💪 Building with sound null safety 💪'));
+  });
+}
+
+class FakeBuildSubCommand extends BuildSubCommand {
+  @override
+  String get description => throw UnimplementedError();
+
+  @override
+  String get name => throw UnimplementedError();
+
+  void test(BuildInfo buildInfo) {
+    displayNullSafetyMode(buildInfo);
+  }
+
+  @override
+  Future<FlutterCommandResult> runCommand() {
+    throw UnimplementedError();
+  }
 }