Add/use addMachineOutputFlag/outputsMachineFormat instead of strings (#171459)

Prepares to make changes such as
https://github.com/flutter/flutter/issues/10621 easier.

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

@@ -87,14 +87,7 @@ class AnalyzeCommand extends FlutterCommand {
       hide: !verboseHelp,
     );
     argParser.addFlag('suggestions', help: 'Show suggestions about the current flutter project.');
-    argParser.addFlag(
-      'machine',
-      negatable: false,
-      help:
-          'Dumps a JSON with a subset of relevant data about the tool, project, '
-          'and environment.',
-      hide: !verboseHelp,
-    );
+    addMachineOutputFlag(verboseHelp: verboseHelp);
 
     // Hidden option to enable a benchmarking mode.
     argParser.addFlag(
@@ -245,7 +238,7 @@ class AnalyzeCommand extends FlutterCommand {
     }
 
     // Don't run pub if asking for machine output.
-    if (boolArg('machine')) {
+    if (outputMachineFormat) {
       return false;
     }
 
@@ -370,7 +363,7 @@ class AnalyzeCommand extends FlutterCommand {
         allProjectValidators: _allProjectValidators,
         userPath: directoryPath,
         processManager: _processManager,
-        machine: boolArg('machine'),
+        machine: outputMachineFormat,
       ).run();
     } else if (boolArg('watch')) {
       await AnalyzeContinuously(

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

@@ -130,15 +130,8 @@ class AttachCommand extends FlutterCommand {
             'using "--machine" instead.',
         hide: !verboseHelp,
       )
-      ..addOption('project-root', hide: !verboseHelp, help: 'Normally used only in run target.')
-      ..addFlag(
-        'machine',
-        hide: !verboseHelp,
-        negatable: false,
-        help:
-            'Handle machine structured JSON command input and provide output '
-            'and progress in machine-friendly format.',
-      );
+      ..addOption('project-root', hide: !verboseHelp, help: 'Normally used only in run target.');
+    addMachineOutputFlag(verboseHelp: verboseHelp);
     usesTrackWidgetCreation(verboseHelp: verboseHelp);
     addDdsOptions(verboseHelp: verboseHelp);
     addDevToolsOptions(verboseHelp: verboseHelp);

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

@@ -61,12 +61,7 @@ class ConfigCommand extends FlutterCommand {
       help: 'The relative path to override a projects build directory.',
       valueHelp: 'out/',
     );
-    argParser.addFlag(
-      'machine',
-      negatable: false,
-      hide: !verboseHelp,
-      help: 'Print config values as json.',
-    );
+    addMachineOutputFlag(verboseHelp: verboseHelp);
     for (final Feature feature in featureFlags.allFeatures) {
       final String? configSetting = feature.configSetting;
       if (configSetting == null) {
@@ -126,7 +121,7 @@ class ConfigCommand extends FlutterCommand {
       return FlutterCommandResult.success();
     }
 
-    if (boolArg('machine')) {
+    if (outputMachineFormat) {
       await handleMachine();
       return FlutterCommandResult.success();
     }

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

@@ -14,11 +14,7 @@ import '../runner/flutter_command.dart';
 
 class DevicesCommand extends FlutterCommand {
   DevicesCommand({bool verboseHelp = false}) {
-    argParser.addFlag(
-      'machine',
-      negatable: false,
-      help: 'Output device information in machine readable structured JSON format.',
-    );
+    addMachineOutputFlag(verboseHelp: verboseHelp);
     argParser.addOption(
       'timeout',
       abbr: 't',
@@ -78,7 +74,7 @@ class DevicesCommand extends FlutterCommand {
       deviceConnectionInterface: deviceConnectionInterface,
     );
 
-    await output.findAndOutputAllTargetDevices(machine: boolArg('machine'));
+    await output.findAndOutputAllTargetDevices(machine: outputMachineFormat);
 
     return FlutterCommandResult.success();
   }

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

@@ -402,6 +402,7 @@ class RunCommand extends RunCommandBase {
     // without needing to know the port.
     addPublishPort(verboseHelp: verboseHelp);
     addIgnoreDeprecationOption();
+    addMachineOutputFlag(verboseHelp: verboseHelp);
     argParser
       ..addFlag(
         'await-first-frame-when-tracing',
@@ -424,14 +425,6 @@ class RunCommand extends RunCommandBase {
       )
       ..addFlag('build', defaultsTo: true, help: 'If necessary, build the app before running.')
       ..addOption('project-root', hide: !verboseHelp, help: 'Specify the project root directory.')
-      ..addFlag(
-        'machine',
-        hide: !verboseHelp,
-        negatable: false,
-        help:
-            'Handle machine structured JSON command input and provide output '
-            'and progress in machine friendly format.',
-      )
       ..addFlag(
         'hot',
         defaultsTo: kHotReloadDefault,
@@ -760,7 +753,7 @@ class RunCommand extends RunCommandBase {
     final bool hotMode = shouldUseHotMode(buildInfo);
     final String? applicationBinaryPath = stringArg(FlutterOptions.kUseApplicationBinary);
 
-    if (boolArg('machine')) {
+    if (outputMachineFormat) {
       if (devices!.length > 1) {
         throwToolExit('"--machine" does not support "-d all".');
       }

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

@@ -78,6 +78,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
     usesDeviceUserOption();
     usesFlavorOption();
     addEnableImpellerFlag(verboseHelp: verboseHelp);
+    addMachineOutputFlag(verboseHelp: verboseHelp);
     addEnableFlutterGpuFlag(verboseHelp: verboseHelp);
 
     argParser
@@ -165,14 +166,6 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
         valueHelp: 'package-name-regexp',
         splitCommas: false,
       )
-      ..addFlag(
-        'machine',
-        hide: !verboseHelp,
-        negatable: false,
-        help:
-            'Handle machine structured JSON command input '
-            'and provide output and progress in machine friendly format.',
-      )
       ..addFlag(
         'update-goldens',
         negatable: false,
@@ -568,7 +561,6 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
       );
     }
 
-    final bool machine = boolArg('machine');
     CoverageCollector? collector;
     if (boolArg('coverage') || boolArg('merge-coverage') || boolArg('branch-coverage')) {
       final Set<String> packagesToInclude = _getCoveragePackages(
@@ -577,7 +569,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
         buildInfo.packageConfig,
       );
       collector = CoverageCollector(
-        verbose: !machine,
+        verbose: !outputMachineFormat,
         libraryNames: packagesToInclude,
         packagesPath: buildInfo.packageConfigPath,
         resolver: await CoverageCollector.getResolver(buildInfo.packageConfigPath),
@@ -587,7 +579,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
     }
 
     TestWatcher? watcher;
-    if (machine) {
+    if (outputMachineFormat) {
       watcher = EventPrinter(parent: collector, out: globals.stdio.stdout);
     } else if (collector != null) {
       watcher = collector;
@@ -649,7 +641,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
         plainNames: plainNames,
         tags: tags,
         excludeTags: excludeTags,
-        machine: machine,
+        machine: outputMachineFormat,
         updateGoldens: boolArg('update-goldens'),
         concurrency: jobs,
         testAssetDirectory: testAssetPath,
@@ -677,7 +669,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
         excludeTags: excludeTags,
         watcher: watcher,
         enableVmService: collector != null || startPaused || enableVmService,
-        machine: machine,
+        machine: outputMachineFormat,
         updateGoldens: boolArg('update-goldens'),
         concurrency: jobs,
         testAssetDirectory: testAssetPath,

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

@@ -241,6 +241,8 @@ abstract class FlutterCommand extends Command<void> {
 
   bool get shouldRunPub => _usesPubOption && boolArg('pub');
 
+  bool get outputMachineFormat => boolArg('machine');
+
   bool get shouldUpdateCache => true;
 
   bool get deprecated => false;
@@ -1280,6 +1282,15 @@ abstract class FlutterCommand extends Command<void> {
     );
   }
 
+  void addMachineOutputFlag({required bool verboseHelp}) {
+    argParser.addFlag(
+      FlutterGlobalOptions.kMachineFlag,
+      negatable: false,
+      help: 'Outputs in a machine readable structured JSON format.',
+      hide: !verboseHelp,
+    );
+  }
+
   /// Returns a [FlutterProject] view of the current directory or a ToolExit error,
   /// if `pubspec.yaml` or `example/pubspec.yaml` is invalid.
   FlutterProject get project => FlutterProject.current();

packages/flutter_tools/test/general.shard/runner/flutter_command_runner_test.dart

@@ -97,7 +97,7 @@ void main() {
         'does not check that Flutter installation is up-to-date with --machine flag present anywhere',
         () async {
           final FlutterCommandRunner runner =
-              createTestCommandRunner(_FlutterCommandWithItsOwnMachineFlag())
+              createTestCommandRunner(_FlutterCommandWithItsOwnMachineFlag(verboseHelp: false))
                   as FlutterCommandRunner;
           final FakeFlutterVersion version = globals.flutterVersion as FakeFlutterVersion;
 
@@ -446,8 +446,8 @@ class FakeStdio extends Stdio {
 }
 
 final class _FlutterCommandWithItsOwnMachineFlag extends FlutterCommand {
-  _FlutterCommandWithItsOwnMachineFlag() {
-    argParser.addFlag('machine', negatable: false);
+  _FlutterCommandWithItsOwnMachineFlag({required bool verboseHelp}) {
+    addMachineOutputFlag(verboseHelp: verboseHelp);
   }
 
   @override