Migrate deferred_components_gen_snapshot_validator to null safety (#83311)

packages/flutter_tools/lib/src/android/deferred_components_gen_snapshot_validator.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:xml/xml.dart';
 import 'package:yaml/yaml.dart';
 
@@ -32,7 +30,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
   /// change. This defaults to true.
   DeferredComponentsGenSnapshotValidator(this.env, {
     bool exitOnFail = true,
-    String title,
+    String? title,
   }) : super(env.projectDir, env.logger, env.platform, exitOnFail: exitOnFail, title: title);
 
   /// The build environment that should be used to find the input files to run
@@ -101,7 +99,11 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
     final Map<int, String> mapping = <int, String>{};
     for (final DeferredComponent component in components) {
       component.assignLoadingUnits(generatedLoadingUnits);
-      for (final LoadingUnit unit in component.loadingUnits) {
+      final Set<LoadingUnit>? loadingUnits = component.loadingUnits;
+      if (loadingUnits == null) {
+        continue;
+      }
+      for (final LoadingUnit unit in loadingUnits) {
         if (!mapping.containsKey(unit.id)) {
           mapping[unit.id] = component.name;
         }
@@ -129,10 +131,10 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
     bool modified = false;
     for (final XmlElement application in document.findAllElements('application')) {
       for (final XmlElement metaData in application.findElements('meta-data')) {
-        final String name = metaData.getAttribute('android:name');
+        final String? name = metaData.getAttribute('android:name');
         if (name == _mappingKey) {
           exists = true;
-          final String storedMappingString = metaData.getAttribute('android:value');
+          final String? storedMappingString = metaData.getAttribute('android:value');
           if (storedMappingString != encodedMapping) {
             metaData.setAttribute('android:value', encodedMapping);
             modified = true;
@@ -182,13 +184,13 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
   bool checkAgainstLoadingUnitsCache(
       List<LoadingUnit> generatedLoadingUnits) {
     final List<LoadingUnit> cachedLoadingUnits = _parseLodingUnitsCache(projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName));
-    loadingUnitComparisonResults = <String, dynamic>{};
+    loadingUnitComparisonResults = <String, Object>{};
     final Set<LoadingUnit> unmatchedLoadingUnits = <LoadingUnit>{};
     final List<LoadingUnit> newLoadingUnits = <LoadingUnit>[];
     if (generatedLoadingUnits == null || cachedLoadingUnits == null) {
-      loadingUnitComparisonResults['new'] = newLoadingUnits;
-      loadingUnitComparisonResults['missing'] = unmatchedLoadingUnits;
-      loadingUnitComparisonResults['match'] = false;
+      loadingUnitComparisonResults!['new'] = newLoadingUnits;
+      loadingUnitComparisonResults!['missing'] = unmatchedLoadingUnits;
+      loadingUnitComparisonResults!['match'] = false;
       return false;
     }
     unmatchedLoadingUnits.addAll(cachedLoadingUnits);
@@ -207,10 +209,10 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
         addedNewIds.add(genUnit.id);
       }
     }
-    loadingUnitComparisonResults['new'] = newLoadingUnits;
-    loadingUnitComparisonResults['missing'] = unmatchedLoadingUnits;
-    loadingUnitComparisonResults['match'] = newLoadingUnits.isEmpty && unmatchedLoadingUnits.isEmpty;
-    return loadingUnitComparisonResults['match'] as bool;
+    loadingUnitComparisonResults!['new'] = newLoadingUnits;
+    loadingUnitComparisonResults!['missing'] = unmatchedLoadingUnits;
+    loadingUnitComparisonResults!['match'] = newLoadingUnits.isEmpty && unmatchedLoadingUnits.isEmpty;
+    return loadingUnitComparisonResults!['match']! as bool;
   }
 
   List<LoadingUnit> _parseLodingUnitsCache(File cacheFile) {
@@ -232,13 +234,13 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
         return loadingUnits;
       }
       if (data['loading-units'] != null) {
-        for (final dynamic loadingUnitData in data['loading-units']) {
+        for (final Object? loadingUnitData in data['loading-units']) {
           if (loadingUnitData is! YamlMap) {
             invalidFiles[cacheFile.path] = "Invalid loading units yaml file, 'loading-units' "
                                              'is not a list of maps.';
             return loadingUnits;
           }
-          final YamlMap loadingUnitDataMap = loadingUnitData as YamlMap;
+          final YamlMap loadingUnitDataMap = loadingUnitData;
           if (loadingUnitDataMap['id'] == null) {
             invalidFiles[cacheFile.path] = 'Invalid loading units yaml file, all '
                                              "loading units must have an 'id'";
@@ -250,7 +252,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
                                                'is not a list.';
               return loadingUnits;
             }
-            for (final dynamic node in loadingUnitDataMap['libraries'] as YamlList) {
+            for (final Object? node in loadingUnitDataMap['libraries'] as YamlList) {
               if (node is! String) {
                 invalidFiles[cacheFile.path] = "Invalid loading units yaml file, 'libraries' "
                                                  'is not a list of strings.';
@@ -265,17 +267,18 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
     // Parse out validated yaml.
     if (data.containsKey('loading-units')) {
       if (data['loading-units'] != null) {
-        for (final dynamic loadingUnitData in data['loading-units']) {
-          final YamlMap loadingUnitDataMap = loadingUnitData as YamlMap;
+        for (final Object? loadingUnitData in data['loading-units']) {
+          final YamlMap? loadingUnitDataMap = loadingUnitData as YamlMap?;
           final List<String> libraries = <String>[];
-          if (loadingUnitDataMap['libraries'] != null) {
-            for (final dynamic node in loadingUnitDataMap['libraries'] as YamlList) {
+          final YamlList? nodes = loadingUnitDataMap?['libraries'] as YamlList?;
+          if (nodes != null) {
+            for (final Object node in nodes.whereType<Object>()) {
               libraries.add(node as String);
             }
           }
           loadingUnits.add(
               LoadingUnit(
-                id: loadingUnitDataMap['id'] as int,
+                id: loadingUnitDataMap!['id'] as int,
                 path: null,
                 libraries: libraries,
               ));
@@ -292,7 +295,7 @@ class DeferredComponentsGenSnapshotValidator extends DeferredComponentsValidator
   /// mismatching or missing cache will result in a failed validation. This
   /// prevents unexpected changes in loading units causing misconfigured
   /// deferred components.
-  void writeLoadingUnitsCache(List<LoadingUnit> generatedLoadingUnits) {
+  void writeLoadingUnitsCache(List<LoadingUnit>? generatedLoadingUnits) {
     generatedLoadingUnits ??= <LoadingUnit>[];
     final File cacheFile = projectDir.childFile(DeferredComponentsValidator.kLoadingUnitsCacheFileName);
     outputs.add(cacheFile);

packages/flutter_tools/test/general.shard/android/deferred_components_gen_snapshot_validator_test.dart

@@ -2,25 +2,24 @@
 // 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/android/deferred_components_gen_snapshot_validator.dart';
 import 'package:flutter_tools/src/android/deferred_components_validator.dart';
+import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/deferred_component.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
-import 'package:flutter_tools/src/globals_null_migrated.dart' as globals;
 
 import '../../src/common.dart';
+import '../../src/fake_process_manager.dart';
 
 void main() {
-  FileSystem fileSystem;
-  BufferLogger logger;
-  Environment env;
+  late FileSystem fileSystem;
+  late BufferLogger logger;
+  late Environment env;
 
   Environment createEnvironment() {
     final Map<String, String> defines = <String, String>{ kDeferredComponents: 'true' };
@@ -32,10 +31,10 @@ void main() {
       inputs: <String, String>{},
       cacheDir: fileSystem.directory('/cache'),
       flutterRootDir: fileSystem.directory('/flutter_root'),
-      artifacts: globals.artifacts,
+      artifacts: Artifacts.test(),
       fileSystem: fileSystem,
       logger: logger,
-      processManager: globals.processManager,
+      processManager: FakeProcessManager.any(),
       platform: FakePlatform(),
       engineVersion: 'invalidEngineVersion',
       generateDartPluginRegistry: false,