Migrate reporting library to null safety (#80320)

packages/flutter_tools/lib/src/android/gradle_utils.dart

@@ -16,7 +16,7 @@ import '../base/utils.dart';
 import '../base/version.dart';
 import '../build_info.dart';
 import '../cache.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../project.dart';
 import '../reporting/reporting.dart';
 

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

@@ -12,7 +12,7 @@ import '../base/os.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../features.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../linux/build_linux.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart' show FlutterCommandResult;

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

@@ -11,7 +11,7 @@ import '../base/common.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../features.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../macos/build_macos.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart' show FlutterCommandResult;

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

@@ -11,7 +11,7 @@ import '../base/common.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../features.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../project.dart';
 import '../runner/flutter_command.dart' show FlutterCommandResult;
 import '../windows/build_windows.dart';

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

@@ -7,7 +7,7 @@
 import '../base/common.dart';
 import '../convert.dart';
 import '../features.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../reporting/reporting.dart';
 import '../runner/flutter_command.dart';
 

packages/flutter_tools/lib/src/drive/web_driver_service.dart

@@ -17,7 +17,7 @@ import '../base/process.dart';
 import '../build_info.dart';
 import '../convert.dart';
 import '../device.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../project.dart';
 import '../resident_runner.dart';
 import '../web/web_runner.dart';

packages/flutter_tools/lib/src/globals.dart

@@ -21,7 +21,6 @@ import 'macos/xcdevice.dart';
 import 'macos/xcode.dart';
 import 'project.dart';
 import 'reporting/crash_reporting.dart';
-import 'reporting/reporting.dart';
 import 'runner/local_engine.dart';
 
 export 'globals_null_migrated.dart';
@@ -30,7 +29,6 @@ Artifacts get artifacts => context.get<Artifacts>();
 BuildSystem get buildSystem => context.get<BuildSystem>();
 CrashReporter get crashReporter => context.get<CrashReporter>();
 Doctor get doctor => context.get<Doctor>();
-Usage get flutterUsage => context.get<Usage>();
 DeviceManager get deviceManager => context.get<DeviceManager>();
 
 FlutterProjectFactory get projectFactory {

packages/flutter_tools/lib/src/globals_null_migrated.dart

@@ -25,6 +25,7 @@ import 'base/user_messages.dart';
 import 'cache.dart';
 import 'ios/plist_parser.dart';
 import 'persistent_tool_state.dart';
+import 'reporting/reporting.dart';
 import 'version.dart';
 
 Cache get cache => context.get<Cache>()!;
@@ -36,6 +37,7 @@ Signals get signals => context.get<Signals>() ?? LocalSignals.instance;
 AndroidStudio? get androidStudio => context.get<AndroidStudio>();
 AndroidSdk? get androidSdk => context.get<AndroidSdk>();
 FlutterVersion get flutterVersion => context.get<FlutterVersion>()!;
+Usage get flutterUsage => context.get<Usage>()!;
 
 PersistentToolState? get persistentToolState => PersistentToolState.instance;
 

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

@@ -21,7 +21,7 @@ import '../build_info.dart';
 import '../convert.dart';
 import '../device.dart';
 import '../device_port_forwarder.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../macos/xcdevice.dart';
 import '../project.dart';
 import '../protocol_discovery.dart';

packages/flutter_tools/lib/src/reporting/disabled_usage.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 part of reporting;
 
 class DisabledUsage implements Usage {
@@ -20,28 +18,28 @@ class DisabledUsage implements Usage {
   set enabled(bool value) { }
 
   @override
-  String get clientId => null;
+  String get clientId => '';
 
   @override
-  void sendCommand(String command, { Map<String, String> parameters }) { }
+  void sendCommand(String command, { Map<String, String>? parameters }) { }
 
   @override
   void sendEvent(
     String category,
     String parameter, {
-    String label,
-    int value,
-    Map<String, String> parameters,
+    String? label,
+    int? value,
+    Map<String, String>? parameters,
   }) { }
 
   @override
-  void sendTiming(String category, String variableName, Duration duration, { String label }) { }
+  void sendTiming(String category, String variableName, Duration duration, { String? label }) { }
 
   @override
   void sendException(dynamic exception) { }
 
   @override
-  Stream<Map<String, dynamic>> get onSend => null;
+  Stream<Map<String, dynamic>> get onSend => const Stream<Map<String, dynamic>>.empty();
 
   @override
   Future<void> ensureAnalyticsSent() => Future<void>.value();

packages/flutter_tools/lib/src/reporting/events.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 part of reporting;
 
 /// A generic usage even that does not involve custom dimensions.
@@ -14,13 +12,13 @@ class UsageEvent {
   UsageEvent(this.category, this.parameter, {
     this.label,
     this.value,
-    @required this.flutterUsage,
+    required this.flutterUsage,
   });
 
   final String category;
   final String parameter;
-  final String label;
-  final int value;
+  final String? label;
+  final int? value;
   final Usage flutterUsage;
 
   void send() {
@@ -37,11 +35,11 @@ class UsageEvent {
 /// sync/transfer "overhead" of updating this number of source files.
 class HotEvent extends UsageEvent {
   HotEvent(String parameter, {
-    @required this.targetPlatform,
-    @required this.sdkName,
-    @required this.emulator,
-    @required this.fullRestart,
-    @required this.fastReassemble,
+    required this.targetPlatform,
+    required this.sdkName,
+    required this.emulator,
+    required this.fullRestart,
+    required this.fastReassemble,
     this.reason,
     this.finalLibraryCount,
     this.syncedLibraryCount,
@@ -53,20 +51,20 @@ class HotEvent extends UsageEvent {
     this.overallTimeInMs,
   }) : super('hot', parameter, flutterUsage: globals.flutterUsage);
 
-  final String reason;
+  final String? reason;
   final String targetPlatform;
   final String sdkName;
   final bool emulator;
   final bool fullRestart;
   final bool fastReassemble;
-  final int finalLibraryCount;
-  final int syncedLibraryCount;
-  final int syncedClassesCount;
-  final int syncedProceduresCount;
-  final int syncedBytes;
-  final int invalidatedSourcesCount;
-  final int transferTimeInMs;
-  final int overallTimeInMs;
+  final int? finalLibraryCount;
+  final int? syncedLibraryCount;
+  final int? syncedClassesCount;
+  final int? syncedProceduresCount;
+  final int? syncedBytes;
+  final int? invalidatedSourcesCount;
+  final int? transferTimeInMs;
+  final int? overallTimeInMs;
 
   @override
   void send() {
@@ -76,7 +74,7 @@ class HotEvent extends UsageEvent {
       CustomDimensions.hotEventEmulator: emulator.toString(),
       CustomDimensions.hotEventFullRestart: fullRestart.toString(),
       if (reason != null)
-        CustomDimensions.hotEventReason: reason,
+        CustomDimensions.hotEventReason: reason!,
       if (finalLibraryCount != null)
         CustomDimensions.hotEventFinalLibraryCount: finalLibraryCount.toString(),
       if (syncedLibraryCount != null)
@@ -103,9 +101,9 @@ class HotEvent extends UsageEvent {
 /// An event that reports the result of a [DoctorValidator]
 class DoctorResultEvent extends UsageEvent {
   DoctorResultEvent({
-    @required this.validator,
-    @required this.result,
-    Usage flutterUsage,
+    required this.validator,
+    required this.result,
+    Usage? flutterUsage,
   }) : super(
     'doctor-result',
     '${validator.runtimeType}',
@@ -139,20 +137,20 @@ class DoctorResultEvent extends UsageEvent {
 /// An event that reports on the result of a pub invocation.
 class PubResultEvent extends UsageEvent {
   PubResultEvent({
-    @required String context,
-    @required String result,
-    @required Usage usage,
+    required String context,
+    required String result,
+    required Usage usage,
   }) : super('pub-result', context, label: result, flutterUsage: usage);
 }
 
 /// An event that reports something about a build.
 class BuildEvent extends UsageEvent {
   BuildEvent(String label, {
-    String command,
-    String settings,
-    String eventError,
-    @required Usage flutterUsage,
-    @required String type,
+    String? command,
+    String? settings,
+    String? eventError,
+    required Usage flutterUsage,
+    required String type,
   }) : _command = command,
   _settings = settings,
   _eventError = eventError,
@@ -165,19 +163,19 @@ class BuildEvent extends UsageEvent {
     flutterUsage: flutterUsage,
   );
 
-  final String _command;
-  final String _settings;
-  final String _eventError;
+  final String? _command;
+  final String? _settings;
+  final String? _eventError;
 
   @override
   void send() {
     final Map<String, String> parameters = _useCdKeys(<CustomDimensions, String>{
       if (_command != null)
-        CustomDimensions.buildEventCommand: _command,
+        CustomDimensions.buildEventCommand: _command!,
       if (_settings != null)
-        CustomDimensions.buildEventSettings: _settings,
+        CustomDimensions.buildEventSettings: _settings!,
       if (_eventError != null)
-        CustomDimensions.buildEventError: _eventError,
+        CustomDimensions.buildEventError: _eventError!,
     });
     flutterUsage.sendEvent(
       category,
@@ -226,7 +224,7 @@ class CommandResultEvent extends UsageEvent {
 class AnalyticsConfigEvent extends UsageEvent {
   AnalyticsConfigEvent({
     /// Whether analytics reporting is being enabled (true) or disabled (false).
-    @required bool enabled,
+    required bool enabled,
   }) : super(
     'analytics',
     'enabled',
@@ -238,11 +236,11 @@ class AnalyticsConfigEvent extends UsageEvent {
 /// An event that reports when the code size measurement is run via `--analyze-size`.
 class CodeSizeEvent extends UsageEvent {
   CodeSizeEvent(String platform, {
-    @required Usage flutterUsage,
+    required Usage flutterUsage,
   }) : super(
     'code-size-analysis',
     platform,
-    flutterUsage: flutterUsage ?? globals.flutterUsage,
+    flutterUsage: flutterUsage
   );
 }
 
@@ -279,14 +277,15 @@ class NullSafetyAnalysisEvent implements UsageEvent {
       return;
     }
     int migrated = 0;
-    LanguageVersion languageVersion;
+    LanguageVersion? languageVersion;
     for (final Package package in packageConfig.packages) {
+      final LanguageVersion? packageLanguageVersion = package.languageVersion;
       if (package.name == currentPackage) {
-        languageVersion = package.languageVersion;
+        languageVersion = packageLanguageVersion;
       }
-      if (package.languageVersion != null &&
-          package.languageVersion.major >= nullSafeVersion.major &&
-          package.languageVersion.minor >= nullSafeVersion.minor) {
+      if (packageLanguageVersion != null &&
+          packageLanguageVersion.major >= nullSafeVersion.major &&
+          packageLanguageVersion.minor >= nullSafeVersion.minor) {
         migrated += 1;
       }
     }

packages/flutter_tools/lib/src/reporting/reporting.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 library reporting;
 
 import 'dart:async';
@@ -20,7 +18,7 @@ import '../build_info.dart';
 import '../dart/language_version.dart';
 import '../doctor_validator.dart';
 import '../features.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../version.dart';
 import 'first_run.dart';
 

packages/flutter_tools/lib/src/reporting/usage.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 part of reporting;
 
 const String _kFlutterUA = 'UA-67589403-6';
@@ -77,24 +75,27 @@ abstract class Usage {
   /// [logFile] are used for testing.
   factory Usage({
     String settingsName = 'flutter',
-    String versionOverride,
-    String configDirOverride,
-    String logFile,
-    AnalyticsFactory analyticsIOFactory,
-    FirstRunMessenger firstRunMessenger,
-    @required bool runningOnBot,
-  }) => _DefaultUsage(settingsName: settingsName,
-                      versionOverride: versionOverride,
-                      configDirOverride: configDirOverride,
-                      logFile: logFile,
-                      analyticsIOFactory: analyticsIOFactory,
-                      runningOnBot: runningOnBot,
-                      firstRunMessenger: firstRunMessenger);
+    String? versionOverride,
+    String? configDirOverride,
+    String? logFile,
+    AnalyticsFactory? analyticsIOFactory,
+    FirstRunMessenger? firstRunMessenger,
+    required bool runningOnBot,
+  }) =>
+      _DefaultUsage.initialize(
+        settingsName: settingsName,
+        versionOverride: versionOverride,
+        configDirOverride: configDirOverride,
+        logFile: logFile,
+        analyticsIOFactory: analyticsIOFactory,
+        runningOnBot: runningOnBot,
+        firstRunMessenger: firstRunMessenger,
+      );
 
   /// Uses the global [Usage] instance to send a 'command' to analytics.
   static void command(String command, {
-    Map<CustomDimensions, Object> parameters,
-  }) => globals.flutterUsage.sendCommand(command, parameters: _useCdKeys(parameters));
+    Map<CustomDimensions, Object>? parameters,
+  }) => globals.flutterUsage.sendCommand(command, parameters: parameters == null ? null : _useCdKeys(parameters));
 
   /// Whether analytics reporting should be suppressed.
   bool get suppressAnalytics;
@@ -118,7 +119,7 @@ abstract class Usage {
   /// keys are well-defined in [CustomDimensions] above.
   void sendCommand(
     String command, {
-    Map<String, String> parameters,
+    Map<String, String>? parameters,
   });
 
   /// Sends an 'event' to the underlying analytics implementation.
@@ -130,9 +131,9 @@ abstract class Usage {
   void sendEvent(
     String category,
     String parameter, {
-    String label,
-    int value,
-    Map<String, String> parameters,
+    String? label,
+    int? value,
+    Map<String, String>? parameters,
   });
 
   /// Sends timing information to the underlying analytics implementation.
@@ -140,7 +141,7 @@ abstract class Usage {
     String category,
     String variableName,
     Duration duration, {
-    String label,
+    String? label,
   });
 
   /// Sends an exception to the underlying analytics implementation.
@@ -164,15 +165,15 @@ typedef AnalyticsFactory = Analytics Function(
   String applicationName,
   String applicationVersion, {
   String analyticsUrl,
-  Directory documentDirectory,
+  Directory? documentDirectory,
 });
 
 Analytics _defaultAnalyticsIOFactory(
   String trackingId,
   String applicationName,
   String applicationVersion, {
-  String analyticsUrl,
-  Directory documentDirectory,
+  String? analyticsUrl,
+  Directory? documentDirectory,
 }) {
   return AnalyticsIO(
     trackingId,
@@ -184,24 +185,34 @@ Analytics _defaultAnalyticsIOFactory(
 }
 
 class _DefaultUsage implements Usage {
-  _DefaultUsage({
+  _DefaultUsage._({
+    required bool suppressAnalytics,
+    required Analytics analytics,
+    required this.firstRunMessenger,
+    required SystemClock clock,
+  })  : _suppressAnalytics = suppressAnalytics,
+        _analytics = analytics,
+        _clock = clock;
+
+  static _DefaultUsage initialize({
     String settingsName = 'flutter',
-    String versionOverride,
-    String configDirOverride,
-    String logFile,
-    AnalyticsFactory analyticsIOFactory,
-    @required this.firstRunMessenger,
-    @required bool runningOnBot,
+    String? versionOverride,
+    String? configDirOverride,
+    String? logFile,
+    AnalyticsFactory? analyticsIOFactory,
+    required FirstRunMessenger? firstRunMessenger,
+    required bool runningOnBot,
   }) {
     final FlutterVersion flutterVersion = globals.flutterVersion;
     final String version = versionOverride ?? flutterVersion.getVersionString(redactUnknownBranches: true);
     final bool suppressEnvFlag = globals.platform.environment['FLUTTER_SUPPRESS_ANALYTICS'] == 'true';
-    final String logFilePath = logFile ?? globals.platform.environment['FLUTTER_ANALYTICS_LOG_FILE'];
+    final String? logFilePath = logFile ?? globals.platform.environment['FLUTTER_ANALYTICS_LOG_FILE'];
     final bool usingLogFile = logFilePath != null && logFilePath.isNotEmpty;
 
-    analyticsIOFactory ??= _defaultAnalyticsIOFactory;
-    _clock = globals.systemClock;
-
+    final AnalyticsFactory analyticsFactory = analyticsIOFactory ?? _defaultAnalyticsIOFactory;
+    bool suppressAnalytics = false;
+    bool skipAnalyticsSessionSetup = false;
+    Analytics? setupAnalytics;
     if (// To support testing, only allow other signals to suppress analytics
         // when analytics are not being shunted to a file.
         !usingLogFile && (
@@ -213,73 +224,81 @@ class _DefaultUsage implements Usage {
         runningOnBot ||
         // Ignore when suppressed by FLUTTER_SUPPRESS_ANALYTICS.
         suppressEnvFlag
-      )) {
+    )) {
       // If we think we're running on a CI system, suppress sending analytics.
       suppressAnalytics = true;
-      _analytics = AnalyticsMock();
-      return;
+      setupAnalytics = AnalyticsMock();
+      skipAnalyticsSessionSetup = true;
     }
-
     if (usingLogFile) {
-      _analytics = LogToFileAnalytics(logFilePath);
+      setupAnalytics ??= LogToFileAnalytics(logFilePath);
     } else {
       try {
         ErrorHandlingFileSystem.noExitOnFailure(() {
-          _analytics = analyticsIOFactory(
+          setupAnalytics = analyticsFactory(
             _kFlutterUA,
             settingsName,
             version,
             documentDirectory: configDirOverride != null
-              ? globals.fs.directory(configDirOverride)
-              : null,
+                ? globals.fs.directory(configDirOverride)
+                : null,
           );
         });
       } on Exception catch (e) {
         globals.printTrace('Failed to initialize analytics reporting: $e');
         suppressAnalytics = true;
-        _analytics = AnalyticsMock();
-        return;
+        setupAnalytics ??= AnalyticsMock();
+        skipAnalyticsSessionSetup = true;
       }
     }
-    assert(_analytics != null);
 
-    // Report a more detailed OS version string than package:usage does by default.
-    _analytics.setSessionValue(
-      cdKey(CustomDimensions.sessionHostOsDetails),
-      globals.os.name,
-    );
-    // Send the branch name as the "channel".
-    _analytics.setSessionValue(
-      cdKey(CustomDimensions.sessionChannelName),
-      flutterVersion.getBranchName(redactUnknownBranches: true),
-    );
-    // For each flutter experimental feature, record a session value in a comma
-    // separated list.
-    final String enabledFeatures = allFeatures
-      .where((Feature feature) {
-        return feature.configSetting != null &&
-               globals.config.getValue(feature.configSetting) == true;
+    final Analytics analytics = setupAnalytics!;
+    if (!skipAnalyticsSessionSetup) {
+      // Report a more detailed OS version string than package:usage does by default.
+      analytics.setSessionValue(
+        cdKey(CustomDimensions.sessionHostOsDetails),
+        globals.os.name,
+      );
+      // Send the branch name as the "channel".
+      analytics.setSessionValue(
+        cdKey(CustomDimensions.sessionChannelName),
+        flutterVersion.getBranchName(redactUnknownBranches: true),
+      );
+      // For each flutter experimental feature, record a session value in a comma
+      // separated list.
+      final String enabledFeatures = allFeatures
+          .where((Feature feature) {
+        final String? configSetting = feature.configSetting;
+        return configSetting != null && globals.config.getValue(configSetting) == true;
       })
-      .map((Feature feature) => feature.configSetting)
-      .join(',');
-    _analytics.setSessionValue(
-      cdKey(CustomDimensions.enabledFlutterFeatures),
-      enabledFeatures,
-    );
-
-    // Record the host as the application installer ID - the context that flutter_tools is running in.
-    if (globals.platform.environment.containsKey('FLUTTER_HOST')) {
-      _analytics.setSessionValue('aiid', globals.platform.environment['FLUTTER_HOST']);
+          .map((Feature feature) => feature.configSetting)
+          .join(',');
+      analytics.setSessionValue(
+        cdKey(CustomDimensions.enabledFlutterFeatures),
+        enabledFeatures,
+      );
+
+      // Record the host as the application installer ID - the context that flutter_tools is running in.
+      if (globals.platform.environment.containsKey('FLUTTER_HOST')) {
+        analytics.setSessionValue('aiid', globals.platform.environment['FLUTTER_HOST']);
+      }
+      analytics.analyticsOpt = AnalyticsOpt.optOut;
     }
-    _analytics.analyticsOpt = AnalyticsOpt.optOut;
+
+    return _DefaultUsage._(
+      suppressAnalytics: suppressAnalytics,
+      analytics: analytics,
+      firstRunMessenger: firstRunMessenger,
+      clock: globals.systemClock,
+    );
   }
 
-  Analytics _analytics;
-  final FirstRunMessenger firstRunMessenger;
+  final Analytics _analytics;
+  final FirstRunMessenger? firstRunMessenger;
 
   bool _printedWelcome = false;
   bool _suppressAnalytics = false;
-  SystemClock _clock;
+  final SystemClock _clock;
 
   @override
   bool get suppressAnalytics => _suppressAnalytics || _analytics.firstRun;
@@ -301,7 +320,7 @@ class _DefaultUsage implements Usage {
   String get clientId => _analytics.clientId;
 
   @override
-  void sendCommand(String command, { Map<String, String> parameters }) {
+  void sendCommand(String command, { Map<String, String>? parameters }) {
     if (suppressAnalytics) {
       return;
     }
@@ -317,9 +336,9 @@ class _DefaultUsage implements Usage {
   void sendEvent(
     String category,
     String parameter, {
-    String label,
-    int value,
-    Map<String, String> parameters,
+    String? label,
+    int? value,
+    Map<String, String>? parameters,
   }) {
     if (suppressAnalytics) {
       return;
@@ -344,7 +363,7 @@ class _DefaultUsage implements Usage {
     String category,
     String variableName,
     Duration duration, {
-    String label,
+    String? label,
   }) {
     if (suppressAnalytics) {
       return;
@@ -384,11 +403,12 @@ class _DefaultUsage implements Usage {
     }
     // Display the welcome message if this is the first run of the tool or if
     // the license terms have changed since it was last displayed.
-    if (firstRunMessenger != null && firstRunMessenger.shouldDisplayLicenseTerms() ?? true) {
+    final FirstRunMessenger? messenger = firstRunMessenger;
+    if (messenger != null && messenger.shouldDisplayLicenseTerms()) {
       globals.printStatus('');
-      globals.printStatus(firstRunMessenger.licenseTerms, emphasis: true);
+      globals.printStatus(messenger.licenseTerms, emphasis: true);
       _printedWelcome = true;
-      firstRunMessenger.confirmLicenseTermsDisplayed();
+      messenger.confirmLicenseTermsDisplayed();
     }
   }
 }
@@ -412,7 +432,7 @@ class LogToFileAnalytics extends AnalyticsMock {
 
   @override
   Future<void> sendScreenView(String viewName, {
-    Map<String, String> parameters,
+    Map<String, String>? parameters,
   }) {
     if (!enabled) {
       return Future<void>.value(null);
@@ -427,7 +447,7 @@ class LogToFileAnalytics extends AnalyticsMock {
 
   @override
   Future<void> sendEvent(String category, String action,
-      {String label, int value, Map<String, String> parameters}) {
+      {String? label, int? value, Map<String, String>? parameters}) {
     if (!enabled) {
       return Future<void>.value(null);
     }
@@ -441,7 +461,7 @@ class LogToFileAnalytics extends AnalyticsMock {
 
   @override
   Future<void> sendTiming(String variableName, int time,
-      {String category, String label}) {
+      {String? category, String? label}) {
     if (!enabled) {
       return Future<void>.value(null);
     }
@@ -496,12 +516,12 @@ class TestUsage implements Usage {
   void printWelcome() { }
 
   @override
-  void sendCommand(String command, {Map<String, String> parameters}) {
+  void sendCommand(String command, {Map<String, String>? parameters}) {
     commands.add(TestUsageCommand(command, parameters: parameters));
   }
 
   @override
-  void sendEvent(String category, String parameter, {String label, int value, Map<String, String> parameters}) {
+  void sendEvent(String category, String parameter, {String? label, int? value, Map<String, String>? parameters}) {
     events.add(TestUsageEvent(category, parameter, label: label, value: value, parameters: parameters));
   }
 
@@ -511,7 +531,7 @@ class TestUsage implements Usage {
   }
 
   @override
-  void sendTiming(String category, String variableName, Duration duration, {String label}) {
+  void sendTiming(String category, String variableName, Duration duration, {String? label}) {
     timings.add(TestTimingEvent(category, variableName, duration, label: label));
   }
 }
@@ -522,7 +542,7 @@ class TestUsageCommand {
   const TestUsageCommand(this.command, {this.parameters});
 
   final String command;
-  final Map<String, String> parameters;
+  final Map<String, String>? parameters;
 
   @override
   bool operator ==(Object other) {
@@ -545,9 +565,9 @@ class TestUsageEvent {
 
   final String category;
   final String parameter;
-  final String label;
-  final int value;
-  final Map<String, String> parameters;
+  final String? label;
+  final int? value;
+  final Map<String, String>? parameters;
 
   @override
   bool operator ==(Object other) {
@@ -578,7 +598,7 @@ class TestTimingEvent {
   final String category;
   final String variableName;
   final Duration duration;
-  final String label;
+  final String? label;
 
   @override
   bool operator ==(Object other) {
@@ -599,7 +619,7 @@ class TestTimingEvent {
   String toString() => 'TestTimingEvent($category, $variableName, $duration, label:$label)';
 }
 
-bool _mapsEqual(Map<dynamic, dynamic> a, Map<dynamic, dynamic> b) {
+bool _mapsEqual(Map<dynamic, dynamic>? a, Map<dynamic, dynamic>? b) {
   if (a == b) {
     return true;
   }

packages/flutter_tools/lib/src/run_hot.dart

@@ -25,7 +25,7 @@ import 'dart/package_map.dart';
 import 'devfs.dart';
 import 'device.dart';
 import 'features.dart';
-import 'globals.dart' as globals;
+import 'globals_null_migrated.dart' as globals;
 import 'reporting/reporting.dart';
 import 'resident_devtools_handler.dart';
 import 'resident_runner.dart';

packages/flutter_tools/test/commands.shard/permeable/packages_test.dart

@@ -18,7 +18,7 @@ import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/packages.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/globals_null_migrated.dart' as globals;
 
 import '../../src/common.dart';
 import '../../src/context.dart';

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

@@ -17,7 +17,7 @@ import 'package:flutter_tools/src/commands/config.dart';
 import 'package:flutter_tools/src/commands/doctor.dart';
 import 'package:flutter_tools/src/doctor.dart';
 import 'package:flutter_tools/src/features.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/globals_null_migrated.dart' as globals;
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:flutter_tools/src/runner/flutter_command.dart';
 import 'package:flutter_tools/src/version.dart';

packages/flutter_tools/test/general.shard/reporting/events_test.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/doctor_validator.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';

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

@@ -15,7 +15,7 @@ import 'package:flutter_tools/src/isolated/devfs_web.dart';
 import 'package:flutter_tools/src/isolated/resident_web_runner.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/device.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/globals_null_migrated.dart' as globals;
 import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/resident_runner.dart';
 import 'package:flutter_tools/src/web/chrome.dart';

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

@@ -21,7 +21,7 @@ import 'package:flutter_tools/src/isolated/resident_web_runner.dart';
 import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/device.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:flutter_tools/src/globals_null_migrated.dart' as globals;
 import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:flutter_tools/src/resident_runner.dart';