Migrate assets, common, icon_tree_shaker to null safety (#91309)

packages/flutter_tools/lib/src/build_info.dart

@@ -634,7 +634,7 @@ String getNameForTargetPlatform(TargetPlatform platform, {DarwinArch? darwinArch
   }
 }
 
-TargetPlatform? getTargetPlatformForName(String platform) {
+TargetPlatform getTargetPlatformForName(String platform) {
   switch (platform) {
     case 'android':
       return TargetPlatform.android;
@@ -669,8 +669,7 @@ TargetPlatform? getTargetPlatformForName(String platform) {
     case 'web-javascript':
       return TargetPlatform.web_javascript;
   }
-  assert(platform != null);
-  return null;
+  throw Exception('Unsupported platform name "$platform"');
 }
 
 AndroidArch getAndroidArchForName(String platform) {

packages/flutter_tools/lib/src/build_system/targets/assets.dart

@@ -2,9 +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:meta/meta.dart';
 import 'package:pool/pool.dart';
 
 import '../../asset.dart';
@@ -28,13 +25,13 @@ import 'icon_tree_shaker.dart';
 ///
 /// Returns a [Depfile] containing all assets used in the build.
 Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
-  Map<String, DevFSContent> additionalContent,
-  @required TargetPlatform targetPlatform,
-  BuildMode buildMode,
+  Map<String, DevFSContent>? additionalContent,
+  required TargetPlatform targetPlatform,
+  BuildMode? buildMode,
 }) async {
   // Check for an SkSL bundle.
-  final String shaderBundlePath = environment.defines[kBundleSkSLPath] ?? environment.inputs[kBundleSkSLPath];
-  final DevFSContent skslBundle = processSkSLBundle(
+  final String? shaderBundlePath = environment.defines[kBundleSkSLPath] ?? environment.inputs[kBundleSkSLPath];
+  final DevFSContent? skslBundle = processSkSLBundle(
     shaderBundlePath,
     engineVersion: environment.engineVersion,
     fileSystem: environment.fileSystem,
@@ -70,7 +67,7 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
 
   final IconTreeShaker iconTreeShaker = IconTreeShaker(
     environment,
-    assetBundle.entries[kFontManifestJson] as DevFSStringContent,
+    assetBundle.entries[kFontManifestJson] as DevFSStringContent?,
     processManager: environment.processManager,
     logger: environment.logger,
     fileSystem: environment.fileSystem,
@@ -118,7 +115,7 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory, {
   // Copy deferred components assets only for release or profile builds.
   // The assets are included in assetBundle.entries as a normal asset when
   // building as debug.
-  if (environment.defines[kDeferredComponents] == 'true') {
+  if (environment.defines[kDeferredComponents] == 'true' && buildMode != null) {
     await Future.wait<void>(
       assetBundle.deferredComponentsEntries.entries.map<Future<void>>((MapEntry<String, Map<String, DevFSContent>> componentEntries) async {
         final Directory componentOutputDir =
@@ -185,11 +182,11 @@ const String kSkSLShaderBundlePath = 'io.flutter.shaders.json';
 ///
 /// If the current target platform is different than the platform constructed
 /// for the bundle, a warning will be printed.
-DevFSContent processSkSLBundle(String bundlePath, {
-  @required TargetPlatform targetPlatform,
-  @required FileSystem fileSystem,
-  @required Logger logger,
-  @required String engineVersion,
+DevFSContent? processSkSLBundle(String? bundlePath, {
+  required TargetPlatform targetPlatform,
+  required FileSystem fileSystem,
+  required Logger logger,
+  String? engineVersion,
 }) {
   if (bundlePath == null) {
     return null;
@@ -202,9 +199,9 @@ DevFSContent processSkSLBundle(String bundlePath, {
   }
 
   // Step 2: validate top level bundle structure.
-  Map<String, Object> bundle;
+  Map<String, Object>? bundle;
   try {
-    final Object rawBundle = json.decode(skSLBundleFile.readAsStringSync());
+    final Object? rawBundle = json.decode(skSLBundleFile.readAsStringSync());
     if (rawBundle is Map<String, Object>) {
       bundle = rawBundle;
     } else {
@@ -219,7 +216,7 @@ DevFSContent processSkSLBundle(String bundlePath, {
   // * The engine revision the bundle was compiled with
   //   is the same as the current revision.
   // * The target platform is the same (this one is a warning only).
-  final String bundleEngineRevision = bundle['engineRevision'] as String;
+  final String? bundleEngineRevision = bundle['engineRevision'] as String?;
   if (bundleEngineRevision != engineVersion) {
     logger.printError(
       'Expected Flutter $bundleEngineRevision, but found $engineVersion\n'
@@ -229,16 +226,19 @@ DevFSContent processSkSLBundle(String bundlePath, {
     throw Exception('SkSL bundle was invalid');
   }
 
-  final TargetPlatform bundleTargetPlatform = getTargetPlatformForName(
-    bundle['platform'] as String);
-  if (bundleTargetPlatform != targetPlatform) {
+  final String? parsedPlatform = bundle['platform'] as String?;
+  TargetPlatform? bundleTargetPlatform;
+  if (parsedPlatform != null) {
+    bundleTargetPlatform = getTargetPlatformForName(parsedPlatform);
+  }
+  if (bundleTargetPlatform == null || bundleTargetPlatform != targetPlatform) {
     logger.printError(
       'The SkSL bundle was created for $bundleTargetPlatform, but the current '
       'platform is $targetPlatform. This may lead to less efficient shader '
       'caching.'
     );
   }
-  return DevFSStringContent(json.encode(<String, Object>{
+  return DevFSStringContent(json.encode(<String, Object?>{
     'data': bundle['data'],
   }));
 }

packages/flutter_tools/lib/src/build_system/targets/common.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:package_config/package_config.dart';
 
 import '../../artifacts.dart';
@@ -51,10 +49,11 @@ class CopyFlutterBundle extends Target {
 
   @override
   Future<void> build(Environment environment) async {
-    if (environment.defines[kBuildMode] == null) {
+    final String? buildModeEnvironment = environment.defines[kBuildMode];
+    if (buildModeEnvironment == null) {
       throw MissingDefineException(kBuildMode, 'copy_flutter_bundle');
     }
-    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final BuildMode buildMode = getBuildModeForName(buildModeEnvironment);
     environment.outputDir.createSync(recursive: true);
 
     // Only copy the prebuilt runtimes and kernel blob in debug mode.
@@ -157,13 +156,15 @@ class KernelSnapshot extends Target {
       fileSystemRoots: <String>[],
       fileSystemScheme: null,
     );
-    if (environment.defines[kBuildMode] == null) {
+    final String? buildModeEnvironment = environment.defines[kBuildMode];
+    if (buildModeEnvironment == null) {
       throw MissingDefineException(kBuildMode, 'kernel_snapshot');
     }
-    if (environment.defines[kTargetPlatform] == null) {
+    final String? targetPlatformEnvironment = environment.defines[kTargetPlatform];
+    if (targetPlatformEnvironment == null) {
       throw MissingDefineException(kTargetPlatform, 'kernel_snapshot');
     }
-    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
+    final BuildMode buildMode = getBuildModeForName(buildModeEnvironment);
     final String targetFile = environment.defines[kTargetFile] ?? environment.fileSystem.path.join('lib', 'main.dart');
     final File packagesFile = environment.projectDir
       .childDirectory('.dart_tool')
@@ -171,12 +172,12 @@ class KernelSnapshot extends Target {
     final String targetFileAbsolute = environment.fileSystem.file(targetFile).absolute.path;
     // everything besides 'false' is considered to be enabled.
     final bool trackWidgetCreation = environment.defines[kTrackWidgetCreation] != 'false';
-    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
+    final TargetPlatform targetPlatform = getTargetPlatformForName(targetPlatformEnvironment);
 
     // This configuration is all optional.
     final List<String> extraFrontEndOptions = decodeCommaSeparated(environment.defines, kExtraFrontEndOptions);
-    final List<String> fileSystemRoots = environment.defines[kFileSystemRoots]?.split(',');
-    final String fileSystemScheme = environment.defines[kFileSystemScheme];
+    final List<String>? fileSystemRoots = environment.defines[kFileSystemRoots]?.split(',');
+    final String? fileSystemScheme = environment.defines[kFileSystemScheme];
 
     TargetModel targetModel = TargetModel.flutter;
     if (targetPlatform == TargetPlatform.fuchsia_x64 ||
@@ -202,7 +203,7 @@ class KernelSnapshot extends Target {
       logger: environment.logger,
     );
 
-    final CompilerOutput output = await compiler.compile(
+    final CompilerOutput? output = await compiler.compile(
       sdkRoot: environment.artifacts.getArtifactPath(
         Artifact.flutterPatchedSdkPath,
         platform: targetPlatform,
@@ -244,23 +245,25 @@ abstract class AotElfBase extends Target {
       reportTimings: false,
       fileSystem: environment.fileSystem,
       logger: environment.logger,
-      xcode: globals.xcode,
+      xcode: globals.xcode!,
       processManager: environment.processManager,
       artifacts: environment.artifacts,
     );
     final String outputPath = environment.buildDir.path;
-    if (environment.defines[kBuildMode] == null) {
+    final String? buildModeEnvironment = environment.defines[kBuildMode];
+    if (buildModeEnvironment == null) {
       throw MissingDefineException(kBuildMode, 'aot_elf');
     }
-    if (environment.defines[kTargetPlatform] == null) {
+    final String? targetPlatformEnvironment = environment.defines[kTargetPlatform];
+    if (targetPlatformEnvironment == null) {
       throw MissingDefineException(kTargetPlatform, 'aot_elf');
     }
     final List<String> extraGenSnapshotOptions = decodeCommaSeparated(environment.defines, kExtraGenSnapshotOptions);
-    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
-    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
-    final String splitDebugInfo = environment.defines[kSplitDebugInfo];
+    final BuildMode buildMode = getBuildModeForName(buildModeEnvironment);
+    final TargetPlatform targetPlatform = getTargetPlatformForName(targetPlatformEnvironment);
+    final String? splitDebugInfo = environment.defines[kSplitDebugInfo];
     final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
-    final String codeSizeDirectory = environment.defines[kCodeSizeDirectory];
+    final String? codeSizeDirectory = environment.defines[kCodeSizeDirectory];
 
     if (codeSizeDirectory != null) {
       final File codeSizeFile = environment.fileSystem

packages/flutter_tools/lib/src/build_system/targets/icon_tree_shaker.dart

@@ -2,9 +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:meta/meta.dart';
 import 'package:mime/mime.dart' as mime;
 import 'package:process/process.dart';
 
@@ -18,9 +15,9 @@ import '../../convert.dart';
 import '../../devfs.dart';
 import '../build_system.dart';
 
-List<Map<String, dynamic>> _getList(dynamic object, String errorMessage) {
-  if (object is List<dynamic>) {
-    return object.cast<Map<String, dynamic>>();
+List<Map<String, Object?>> _getList(Object? object, String errorMessage) {
+  if (object is List<Object?>) {
+    return object.cast<Map<String, Object?>>();
   }
   throw IconTreeShakerException._(errorMessage);
 }
@@ -39,11 +36,11 @@ class IconTreeShaker {
   /// font subsetting has been requested in a debug build mode.
   IconTreeShaker(
     this._environment,
-    DevFSStringContent fontManifest, {
-    @required ProcessManager processManager,
-    @required Logger logger,
-    @required FileSystem fileSystem,
-    @required Artifacts artifacts,
+    DevFSStringContent? fontManifest, {
+    required ProcessManager processManager,
+    required Logger logger,
+    required FileSystem fileSystem,
+    required Artifacts artifacts,
   }) : assert(_environment != null),
        assert(processManager != null),
        assert(logger != null),
@@ -81,9 +78,9 @@ class IconTreeShaker {
   ];
 
   final Environment _environment;
-  final String _fontManifest;
-  Future<void> _iconDataProcessing;
-  Map<String, _IconTreeShakerData> _iconData;
+  final String? _fontManifest;
+  Future<void>? _iconDataProcessing;
+  Map<String, _IconTreeShakerData>? _iconData;
 
   final ProcessManager _processManager;
   final Logger _logger;
@@ -120,7 +117,7 @@ class IconTreeShaker {
     final Set<String> familyKeys = iconData.keys.toSet();
 
     final Map<String, String> fonts = await _parseFontJson(
-      _fontManifest,
+      _fontManifest!, // Guarded by `enabled`.
       familyKeys,
     );
 
@@ -137,10 +134,14 @@ class IconTreeShaker {
 
     final Map<String, _IconTreeShakerData> result = <String, _IconTreeShakerData>{};
     for (final MapEntry<String, String> entry in fonts.entries) {
+      final List<int>? codePoints = iconData[entry.key];
+      if (codePoints == null) {
+        throw IconTreeShakerException._('Expected to font code points for ${entry.key}, but none were found.');
+      }
       result[entry.value] = _IconTreeShakerData(
         family: entry.key,
         relativePath: entry.value,
-        codePoints: iconData[entry.key],
+        codePoints: codePoints,
       );
     }
     _iconData = result;
@@ -156,9 +157,9 @@ class IconTreeShaker {
   /// If the font-subset subprocess fails, it will [throwToolExit].
   /// Otherwise, it will return true.
   Future<bool> subsetFont({
-    @required File input,
-    @required String outputPath,
-    @required String relativePath,
+    required File input,
+    required String outputPath,
+    required String relativePath,
   }) async {
     if (!enabled) {
       return false;
@@ -166,7 +167,7 @@ class IconTreeShaker {
     if (input.lengthSync() < 12) {
       return false;
     }
-    final String mimeType = mime.lookupMimeType(
+    final String? mimeType = mime.lookupMimeType(
       input.path,
       headerBytes: await input.openRead(0, 12).first,
     );
@@ -176,7 +177,7 @@ class IconTreeShaker {
     await (_iconDataProcessing ??= _getIconData(_environment));
     assert(_iconData != null);
 
-    final _IconTreeShakerData iconTreeShakerData = _iconData[relativePath];
+    final _IconTreeShakerData? iconTreeShakerData = _iconData![relativePath];
     if (iconTreeShakerData == null) {
       return false;
     }
@@ -220,22 +221,22 @@ class IconTreeShaker {
     Set<String> families,
   ) async {
     final Map<String, String> result = <String, String>{};
-    final List<Map<String, dynamic>> fontList = _getList(
+    final List<Map<String, Object?>> fontList = _getList(
       json.decode(fontManifestData),
       'FontManifest.json invalid: expected top level to be a list of objects.',
     );
 
-    for (final Map<String, dynamic> map in fontList) {
-      if (map['family'] is! String) {
+    for (final Map<String, Object?> map in fontList) {
+      final Object? familyKey = map['family'];
+      if (familyKey is! String) {
         throw IconTreeShakerException._(
           'FontManifest.json invalid: expected the family value to be a string, '
           'got: ${map['family']}.');
       }
-      final String familyKey = map['family'] as String;
       if (!families.contains(familyKey)) {
         continue;
       }
-      final List<Map<String, dynamic>> fonts = _getList(
+      final List<Map<String, Object?>> fonts = _getList(
         map['fonts'],
         'FontManifest.json invalid: expected "fonts" to be a list of objects.',
       );
@@ -244,12 +245,13 @@ class IconTreeShaker {
           'This tool cannot process icon fonts with multiple fonts in a '
           'single family.');
       }
-      if (fonts.first['asset'] is! String) {
+      final Object? asset = fonts.first['asset'];
+      if (asset is! String) {
         throw IconTreeShakerException._(
           'FontManifest.json invalid: expected "asset" value to be a string, '
           'got: ${map['assets']}.');
       }
-      result[familyKey] = fonts.first['asset'] as String;
+      result[familyKey] = asset;
     }
     return result;
   }
@@ -273,19 +275,18 @@ class IconTreeShaker {
     if (constFinderProcessResult.exitCode != 0) {
       throw IconTreeShakerException._('ConstFinder failure: ${constFinderProcessResult.stderr}');
     }
-    final dynamic jsonDecode = json.decode(constFinderProcessResult.stdout as String);
-    if (jsonDecode is! Map<String, dynamic>) {
+    final Object? constFinderMap = json.decode(constFinderProcessResult.stdout as String);
+    if (constFinderMap is! Map<String, Object?>) {
       throw IconTreeShakerException._(
         'Invalid ConstFinder output: expected a top level JSON object, '
-        'got $jsonDecode.');
+        'got $constFinderMap.');
     }
-    final Map<String, dynamic> constFinderMap = jsonDecode as Map<String, dynamic>;
     final _ConstFinderResult constFinderResult = _ConstFinderResult(constFinderMap);
     if (constFinderResult.hasNonConstantLocations) {
       _logger.printError('This application cannot tree shake icons fonts. '
                          'It has non-constant instances of IconData at the '
                          'following locations:', emphasis: true);
-      for (final Map<String, dynamic> location in constFinderResult.nonConstantLocations) {
+      for (final Map<String, Object?> location in constFinderResult.nonConstantLocations) {
         _logger.printError(
           '- ${location['file']}:${location['line']}:${location['column']}',
           indent: 2,
@@ -300,22 +301,24 @@ class IconTreeShaker {
 
   Map<String, List<int>> _parseConstFinderResult(_ConstFinderResult constants) {
     final Map<String, List<int>> result = <String, List<int>>{};
-    for (final Map<String, dynamic> iconDataMap in constants.constantInstances) {
-      if ((iconDataMap['fontPackage'] ?? '') is! String || // Null is ok here.
-           iconDataMap['fontFamily'] is! String ||
-           iconDataMap['codePoint'] is! num) {
+    for (final Map<String, Object?> iconDataMap in constants.constantInstances) {
+      final Object? package = iconDataMap['fontPackage'];
+      final Object? fontFamily = iconDataMap['fontFamily'];
+      final Object? codePoint = iconDataMap['codePoint'];
+      if ((package ?? '') is! String || // Null is ok here.
+          fontFamily is! String ||
+          codePoint is! num) {
         throw IconTreeShakerException._(
           'Invalid ConstFinder result. Expected "fontPackage" to be a String, '
           '"fontFamily" to be a String, and "codePoint" to be an int, '
           'got: $iconDataMap.');
       }
-      final String package = iconDataMap['fontPackage'] as String;
-      final String family = iconDataMap['fontFamily'] as String;
+      final String family = fontFamily;
       final String key = package == null
         ? family
         : 'packages/$package/$family';
       result[key] ??= <int>[];
-      result[key].add((iconDataMap['codePoint'] as num).round());
+      result[key]!.add(codePoint.round());
     }
     return result;
   }
@@ -324,25 +327,17 @@ class IconTreeShaker {
 class _ConstFinderResult {
   _ConstFinderResult(this.result);
 
-  final Map<String, dynamic> result;
+  final Map<String, Object?> result;
 
-  List<Map<String, dynamic>> _constantInstances;
-  List<Map<String, dynamic>> get constantInstances {
-    _constantInstances ??= _getList(
-      result['constantInstances'],
-      'Invalid ConstFinder output: Expected "constInstances" to be a list of objects.',
-    );
-    return _constantInstances;
-  }
+  late final List<Map<String, Object?>> constantInstances = _getList(
+    result['constantInstances'],
+    'Invalid ConstFinder output: Expected "constInstances" to be a list of objects.',
+  );
 
-  List<Map<String, dynamic>> _nonConstantLocations;
-  List<Map<String, dynamic>> get nonConstantLocations {
-    _nonConstantLocations ??= _getList(
-      result['nonConstantLocations'],
-      'Invalid ConstFinder output: Expected "nonConstLocations" to be a list of objects',
-    );
-    return _nonConstantLocations;
-  }
+  late final List<Map<String, Object?>> nonConstantLocations = _getList(
+    result['nonConstantLocations'],
+    'Invalid ConstFinder output: Expected "nonConstLocations" to be a list of objects',
+  );
 
   bool get hasNonConstantLocations => nonConstantLocations.isNotEmpty;
 }
@@ -352,9 +347,9 @@ class _ConstFinderResult {
 class _IconTreeShakerData {
   /// All parameters are required.
   const _IconTreeShakerData({
-    @required this.family,
-    @required this.relativePath,
-    @required this.codePoints,
+    required this.family,
+    required this.relativePath,
+    required this.codePoints,
   }) : assert(family != null),
        assert(relativePath != null),
        assert(codePoints != null);

packages/flutter_tools/lib/src/compile.dart

@@ -196,7 +196,7 @@ class KernelCompiler {
     required ProcessManager processManager,
     required Artifacts artifacts,
     required List<String> fileSystemRoots,
-    required String fileSystemScheme,
+    String? fileSystemScheme,
     @visibleForTesting StdoutHandler? stdoutHandler,
   }) : _logger = logger,
        _fileSystem = fileSystem,
@@ -210,7 +210,7 @@ class KernelCompiler {
   final Artifacts _artifacts;
   final ProcessManager _processManager;
   final Logger _logger;
-  final String _fileSystemScheme;
+  final String? _fileSystemScheme;
   final List<String> _fileSystemRoots;
   final StdoutHandler _stdoutHandler;
 

packages/flutter_tools/test/general.shard/build_system/targets/assets_test.dart

@@ -203,7 +203,7 @@ flutter:
     fileSystem.file('bundle.sksl').writeAsStringSync(json.encode(
       <String, Object>{
         'engineRevision': '2',
-        'platform': 'fuchsia',
+        'platform': 'fuchsia-arm64',
         'data': <String, Object>{}
       }
     ));

packages/flutter_tools/test/general.shard/build_system/targets/icon_tree_shaker_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:file/memory.dart';
 import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
@@ -13,7 +11,6 @@ import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/icon_tree_shaker.dart';
 import 'package:flutter_tools/src/devfs.dart';
-import 'package:meta/meta.dart';
 
 import '../../../src/common.dart';
 import '../../../src/fake_process_manager.dart';
@@ -27,16 +24,16 @@ const String outputPath = '/output/fonts/MaterialIcons-Regular.otf';
 const String relativePath = 'fonts/MaterialIcons-Regular.otf';
 
 void main() {
-  BufferLogger logger;
-  MemoryFileSystem fileSystem;
-  FakeProcessManager processManager;
-  Artifacts artifacts;
-  DevFSStringContent fontManifestContent;
+  late BufferLogger logger;
+  late MemoryFileSystem fileSystem;
+  late FakeProcessManager processManager;
+  late Artifacts artifacts;
+  late DevFSStringContent fontManifestContent;
 
-  String dartPath;
-  String constFinderPath;
-  String fontSubsetPath;
-  List<String> fontSubsetArgs;
+  late String dartPath;
+  late String constFinderPath;
+  late String fontSubsetPath;
+  late List<String> fontSubsetArgs;
 
   List<String> _getConstFinderArgs(String appDillPath) => <String>[
     dartPath,
@@ -65,7 +62,7 @@ void main() {
     int exitCode = 0,
     String stdout = '',
     String stderr = '',
-    @required CompleterIOSink stdinSink,
+    required CompleterIOSink stdinSink,
   }) {
     assert(stdinSink != null);
     stdinSink.clear();