Fix error in type cast. (#97778)

packages/flutter_tools/lib/src/device.dart

@@ -980,7 +980,7 @@ class DebuggingOptions {
       debuggingEnabled: (json['debuggingEnabled'] as bool?)!,
       startPaused: (json['startPaused'] as bool?)!,
       dartFlags: (json['dartFlags'] as String?)!,
-      dartEntrypointArgs: ((json['dartEntrypointArgs'] as List<String>?)?.cast<String>())!,
+      dartEntrypointArgs: ((json['dartEntrypointArgs'] as List<dynamic>?)?.cast<String>())!,
       disableServiceAuthCodes: (json['disableServiceAuthCodes'] as bool?)!,
       enableDds: (json['enableDds'] as bool?)!,
       enableSoftwareRendering: (json['enableSoftwareRendering'] as bool?)!,

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

@@ -9,7 +9,9 @@ import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/base/user_messages.dart';
+import 'package:flutter_tools/src/base/utils.dart';
 import 'package:flutter_tools/src/build_info.dart';
+import 'package:flutter_tools/src/convert.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/project.dart';
 import 'package:test/fake.dart';
@@ -508,6 +510,29 @@ void main() {
     expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, nullAssertions: true)), '--null_assertions');
     expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '--foo', nullAssertions: true)), '--foo,--null_assertions');
   });
+
+  group('JSON encode DebuggingOptions', () {
+    testWithoutContext('can preserve the original options', () {
+      final DebuggingOptions original = DebuggingOptions.enabled(
+        BuildInfo.debug,
+        startPaused: true,
+        disableServiceAuthCodes: true,
+        enableDds: false,
+        dartEntrypointArgs: <String>['a', 'b'],
+        dartFlags: 'c',
+        deviceVmServicePort: 1234,
+      );
+      final String jsonString = json.encode(original.toJson());
+      final Map<String, dynamic> decoded = castStringKeyedMap(json.decode(jsonString))!;
+      final DebuggingOptions deserialized = DebuggingOptions.fromJson(decoded, BuildInfo.debug);
+      expect(deserialized.startPaused, original.startPaused);
+      expect(deserialized.disableServiceAuthCodes, original.disableServiceAuthCodes);
+      expect(deserialized.enableDds, original.enableDds);
+      expect(deserialized.dartEntrypointArgs, original.dartEntrypointArgs);
+      expect(deserialized.dartFlags, original.dartFlags);
+      expect(deserialized.deviceVmServicePort, original.deviceVmServicePort);
+    });
+  });
 }
 
 class TestDeviceManager extends DeviceManager {