Migrate build_system, exceptions, and source to null safety (#83147)

packages/flutter_tools/lib/executable.dart

@@ -48,7 +48,7 @@ import 'src/commands/update_packages.dart';
 import 'src/commands/upgrade.dart';
 import 'src/devtools_launcher.dart';
 import 'src/features.dart';
-import 'src/globals.dart' as globals;
+import 'src/globals_null_migrated.dart' as globals;
 // Files in `isolated` are intentionally excluded from google3 tooling.
 import 'src/isolated/mustache_template.dart';
 import 'src/isolated/resident_web_runner.dart';

packages/flutter_tools/lib/src/build_system/exceptions.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 '../base/file_system.dart';
 
 import 'build_system.dart';

packages/flutter_tools/lib/src/build_system/source.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 '../artifacts.dart';
 import '../base/file_system.dart';
 import '../build_info.dart';
@@ -76,7 +74,7 @@ class SourceVisitor implements ResolvedFiles {
         .replaceAllMapped(_separatorExpr, (Match match) => '${match.group(1)}\n')
         .split('\n')
     // Expand escape sequences, so that '\ ', for example,ß becomes ' '
-        .map<String>((String path) => path.replaceAllMapped(_escapeExpr, (Match match) => match.group(1)).trim())
+        .map<String>((String path) => path.replaceAllMapped(_escapeExpr, (Match match) => match.group(1)!).trim())
         .where((String path) => path.isNotEmpty)
         .toSet()
         .map(environment.fileSystem.file);
@@ -93,7 +91,7 @@ class SourceVisitor implements ResolvedFiles {
     final List<String> segments = <String>[];
     final List<String> rawParts = pattern.split('/');
     final bool hasWildcard = rawParts.last.contains('*');
-    String wildcardFile;
+    String? wildcardFile;
     if (hasWildcard) {
       wildcardFile = rawParts.removeLast();
     }
@@ -141,7 +139,7 @@ class SourceVisitor implements ResolvedFiles {
     // example, `foo_*_.dart`. We want to match `foo_b_.dart` but not
     // `foo_.dart`. To do so, we first subtract the first section from the
     // string if the first segment matches.
-    final List<String> wildcardSegments = wildcardFile.split('*');
+    final List<String> wildcardSegments = wildcardFile?.split('*') ?? <String>[];
     if (wildcardSegments.length > 2) {
       throw InvalidPatternException(pattern);
     }
@@ -171,7 +169,7 @@ class SourceVisitor implements ResolvedFiles {
   /// To increase the performance of builds that use a known revision of Flutter,
   /// these are updated to point towards the engine.version file instead of
   /// the artifact itself.
-  void visitArtifact(Artifact artifact, TargetPlatform platform, BuildMode mode) {
+  void visitArtifact(Artifact artifact, TargetPlatform? platform, BuildMode? mode) {
     // This is not a local engine.
     if (environment.engineVersion != null) {
       sources.add(environment.flutterRootDir
@@ -232,7 +230,7 @@ abstract class Source {
   /// The source is provided by an [Artifact].
   ///
   /// If [artifact] points to a directory then all child files are included.
-  const factory Source.artifact(Artifact artifact, {TargetPlatform platform, BuildMode mode}) = _ArtifactSource;
+  const factory Source.artifact(Artifact artifact, {TargetPlatform? platform, BuildMode? mode}) = _ArtifactSource;
 
   /// The source is provided by an [HostArtifact].
   ///
@@ -269,8 +267,8 @@ class _ArtifactSource implements Source {
   const _ArtifactSource(this.artifact, { this.platform, this.mode });
 
   final Artifact artifact;
-  final TargetPlatform platform;
-  final BuildMode mode;
+  final TargetPlatform? platform;
+  final BuildMode? mode;
 
   @override
   void accept(SourceVisitor visitor) => visitor.visitArtifact(artifact, platform, mode);

packages/flutter_tools/lib/src/bundle.dart

@@ -21,7 +21,7 @@ import 'build_system/targets/common.dart';
 import 'cache.dart';
 import 'convert.dart';
 import 'devfs.dart';
-import 'globals.dart' as globals;
+import 'globals_null_migrated.dart' as globals;
 import 'project.dart';
 
 String get defaultMainPath => globals.fs.path.join('lib', 'main.dart');

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

@@ -10,7 +10,7 @@ import '../build_info.dart';
 import '../commands/build_linux.dart';
 import '../commands/build_macos.dart';
 import '../commands/build_windows.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../runner/flutter_command.dart';
 import 'build_aar.dart';
 import 'build_apk.dart';

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

@@ -18,7 +18,7 @@ import '../build_system/build_system.dart';
 import '../build_system/targets/ios.dart';
 import '../cache.dart';
 import '../flutter_plugins.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../macos/cocoapod_utils.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart' show DevelopmentArtifact, FlutterCommandResult;

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

@@ -14,7 +14,7 @@ import '../cache.dart';
 import '../dart/generate_synthetic_packages.dart';
 import '../dart/pub.dart';
 import '../flutter_plugins.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../plugins.dart';
 import '../project.dart';
 import '../reporting/reporting.dart';

packages/flutter_tools/lib/src/globals.dart

@@ -6,7 +6,6 @@
 
 import 'android/gradle_utils.dart';
 import 'base/context.dart';
-import 'build_system/build_system.dart';
 import 'device.dart';
 import 'doctor.dart';
 import 'fuchsia/fuchsia_sdk.dart';
@@ -21,7 +20,6 @@ import 'runner/local_engine.dart';
 
 export 'globals_null_migrated.dart';
 
-BuildSystem get buildSystem => context.get<BuildSystem>();
 CrashReporter get crashReporter => context.get<CrashReporter>();
 Doctor get doctor => context.get<Doctor>();
 DeviceManager get deviceManager => context.get<DeviceManager>();

packages/flutter_tools/lib/src/globals_null_migrated.dart

@@ -23,6 +23,7 @@ import 'base/template.dart';
 import 'base/terminal.dart';
 import 'base/time.dart';
 import 'base/user_messages.dart';
+import 'build_system/build_system.dart';
 import 'cache.dart';
 import 'ios/ios_workflow.dart';
 import 'ios/plist_parser.dart';
@@ -33,6 +34,7 @@ import 'reporting/reporting.dart';
 import 'version.dart';
 
 Artifacts? get artifacts => context.get<Artifacts>();
+BuildSystem? get buildSystem => context.get<BuildSystem>();
 Cache get cache => context.get<Cache>()!;
 Config get config => context.get<Config>()!;
 HttpClientFactory? get httpClientFactory => context.get<HttpClientFactory>();

packages/flutter_tools/lib/src/resident_runner.dart

@@ -35,7 +35,7 @@ import 'convert.dart';
 import 'devfs.dart';
 import 'device.dart';
 import 'features.dart';
-import 'globals.dart' as globals;
+import 'globals_null_migrated.dart' as globals;
 import 'project.dart';
 import 'resident_devtools_handler.dart';
 import 'run_cold.dart';

packages/flutter_tools/lib/src/web/compile.dart

@@ -13,7 +13,7 @@ import '../build_system/build_system.dart';
 import '../build_system/targets/web.dart';
 import '../cache.dart';
 import '../flutter_plugins.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../platform_plugins.dart';
 import '../plugins.dart';
 import '../project.dart';

packages/flutter_tools/test/general.shard/build_system/build_system_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 'dart:async';
 
 import 'package:file/memory.dart';
@@ -21,15 +19,15 @@ import '../../src/common.dart';
 import '../../src/fake_process_manager.dart';
 
 void main() {
-  FileSystem fileSystem;
-  Environment environment;
-  Target fooTarget;
-  Target barTarget;
-  Target fizzTarget;
-  Target sharedTarget;
-  int fooInvocations;
-  int barInvocations;
-  int shared;
+  late FileSystem fileSystem;
+  late Environment environment;
+  late Target fooTarget;
+  late Target barTarget;
+  late Target fizzTarget;
+  late Target sharedTarget;
+  late int fooInvocations;
+  late int barInvocations;
+  late int shared;
 
   setUp(() {
     fileSystem = MemoryFileSystem.test();
@@ -136,7 +134,7 @@ void main() {
 
     expect(stampFile, exists);
 
-    final Map<String, dynamic> stampContents = castStringKeyedMap(
+    final Map<String, Object?>? stampContents = castStringKeyedMap(
       json.decode(stampFile.readAsStringSync()));
 
     expect(stampContents, containsPair('inputs', <Object>['/foo.dart']));
@@ -312,7 +310,7 @@ void main() {
   testWithoutContext('Can describe itself with JSON output', () {
     environment.buildDir.createSync(recursive: true);
 
-    expect(fooTarget.toJson(environment), <String, dynamic>{
+    expect(fooTarget.toJson(environment), <String, Object?>{
       'inputs':  <Object>[
         '/foo.dart',
       ],
@@ -685,7 +683,7 @@ void main() {
 
 }
 
-BuildSystem setUpBuildSystem(FileSystem fileSystem, [FakePlatform platform]) {
+BuildSystem setUpBuildSystem(FileSystem fileSystem, [FakePlatform? platform]) {
   return FlutterBuildSystem(
     fileSystem: fileSystem,
     logger: BufferLogger.test(),
@@ -694,16 +692,17 @@ BuildSystem setUpBuildSystem(FileSystem fileSystem, [FakePlatform platform]) {
 }
 
 class TestTarget extends Target {
-  TestTarget([this._build, this._canSkip]);
+  TestTarget([Future<void> Function(Environment environment)? build, this._canSkip])
+      : _build = build ?? ((Environment environment) async {});
 
   final Future<void> Function(Environment environment) _build;
 
-  final bool Function(Environment environment) _canSkip;
+  final bool Function(Environment environment)? _canSkip;
 
   @override
   bool canSkip(Environment environment) {
     if (_canSkip != null) {
-      return _canSkip(environment);
+      return _canSkip!(environment);
     }
     return super.canSkip(environment);
   }

packages/flutter_tools/test/general.shard/build_system/exceptions_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/base/file_system.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/exceptions.dart';
@@ -65,12 +63,8 @@ void main() {
 }
 
 class TestTarget extends Target {
-  TestTarget([this._build]);
-
-  final Future<void> Function(Environment environment) _build;
-
   @override
-  Future<void> build(Environment environment) => _build(environment);
+  Future<void> build(Environment environment) async {}
 
   @override
   List<Target> dependencies = <Target>[];

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

@@ -18,7 +18,7 @@ import 'package:flutter_tools/src/commands/build_linux.dart';
 import 'package:flutter_tools/src/commands/build_macos.dart';
 import 'package:flutter_tools/src/commands/build_web.dart';
 import 'package:flutter_tools/src/commands/build_windows.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/runner/flutter_command.dart';
 
 import '../../src/common.dart';

packages/flutter_tools/test/src/test_build_system.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 'dart:async';
 
 import 'package:flutter_tools/src/build_system/build_system.dart';
@@ -28,21 +26,21 @@ class TestBuildSystem implements BuildSystem {
       _onRun = null;
 
   final List<BuildResult> _results;
-  final BuildResult _singleResult;
-  final dynamic _exception;
-  final void Function(Target target, Environment environment) _onRun;
+  final BuildResult? _singleResult;
+  final Object? _exception;
+  final void Function(Target target, Environment environment)? _onRun;
   int _nextResult = 0;
 
   @override
   Future<BuildResult> build(Target target, Environment environment, {BuildSystemConfig buildSystemConfig = const BuildSystemConfig()}) async {
     if (_onRun != null) {
-      _onRun(target, environment);
+      _onRun?.call(target, environment);
     }
     if (_exception != null) {
-      throw _exception;
+      throw _exception!;
     }
     if (_singleResult != null) {
-      return _singleResult;
+      return _singleResult!;
     }
     if (_nextResult >= _results.length) {
       throw StateError('Unexpected build request of ${target.name}');
@@ -51,15 +49,15 @@ class TestBuildSystem implements BuildSystem {
   }
 
   @override
-  Future<BuildResult> buildIncremental(Target target, Environment environment, BuildResult previousBuild) async {
+  Future<BuildResult> buildIncremental(Target target, Environment environment, BuildResult? previousBuild) async {
     if (_onRun != null) {
-      _onRun(target, environment);
+      _onRun?.call(target, environment);
     }
     if (_exception != null) {
-      throw _exception;
+      throw _exception!;
     }
     if (_singleResult != null) {
-      return _singleResult;
+      return _singleResult!;
     }
     if (_nextResult >= _results.length) {
       throw StateError('Unexpected buildIncremental request of ${target.name}');