Running apps with sound null safety from VSCode or Android Studio throws #68627
Description
Running simple Flutter apps with null safety from VSCode or Android Studio triggers a throw in the WidgetInspectorService:
Repro steps for VSCode
- Create simple null safety app:
flutter create nulltest cd nulltest dart migrate --apply-changes --no-web-preview - Open VSCode:
code . - Open
lib/main.dart - Open
launch.json(cmd-shift-p + type launch.json) - Change:
to:
"type": "dart","type": "dart", "args": [ "--enable-experiment=non-nullable", ], - Hit F5
=>
�[38;5;248mLaunching lib/main.dart on Android SDK built for x86 in debug mode...�[39;49m
lib/main.dart
✓ Built build/app/outputs/flutter-apk/app-debug.apk.
Connecting to VM Service at ws://127.0.0.1:53806/6tm7oVyrvok=/ws
D/EGL_emulation( 7933): eglMakeCurrent: 0xeec7eda0: ver 3 0 (tinfo 0xe3a8c350)
�[38;5;248m════════ Exception caught by Flutter framework ═════════════════════════════════�[39;49m
�[38;5;244mThe following _CastError was thrown during a service extension callback for "ext.flutter.inspector.setPubRootDirectories":�[39;49m
type 'Null' is not a subtype of type 'String' in type cast
�[38;5;244mWhen the exception was thrown, this was the stack�[39;49m
�[38;5;244m#0 List.length= (dart:core-patch/growable_array.dart:148:12)�[39;49m
�[38;5;244m#1 WidgetInspectorService._registerServiceExtensionVarArgs.<anonymous closure>.<anonymous closure>�[39;49m
package:flutter/…/widgets/widget_inspector.dart
�[38;5;244m#2 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)�[39;49m
�[38;5;244m#3 WidgetInspectorService._registerServiceExtensionVarArgs.<anonymous closure>�[39;49m
package:flutter/…/widgets/widget_inspector.dart
�[38;5;244m#4 BindingBase.registerServiceExtension.<anonymous closure>�[39;49m
package:flutter/…/foundation/binding.dart
�[38;5;244m...�[39;49m
�[38;5;248m════════════════════════════════════════════════════════════════════════════════�[39;49m
Error handling 'serviceExtension' custom request: ext.flutter.inspector.setPubRootDirectories: (-32000) Server error
{"exception":"type 'Null' is not a subtype of type 'String' in type cast","stack":"#0 List.length= (dart:core-patch/growable_array.dart:148:12)\n#1 WidgetInspectorService._registerServiceExtensionVarArgs.<anonymous closure>.<anonymous closure> (package:flutter/src/widgets/widget_inspector.dart:889:20)\n#2 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)\n#3 WidgetInspectorService._registerServiceExtensionVarArgs.<anonymous closure> (package:flutter/src/widgets/widget_inspector.dart:885:20)\n#4 BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart:546:32)\n<asynchronous suspension>\n#5 BindingBase.registerServiceExtension.<anonymous closure> (package:flutter/src/foundation/binding.dart)\n#6 _runExtension (dart:developer-patch/developer.dart:84:23)\n","method":"ext.flutter.inspector.setPubRootDirectories"}
Repro steps for Android Studio
- Step 1 from VSCode above
- Open Android Studio
- File > Open Existing Project + pick folder with project
- Click Run > Edit Configurations, and in 'Additional arguments' add
--enable-experiment=non-nullable - Hit F5
Version information
mit-macbookpro4:foo mit$ flutter --version
Flutter 1.24.0-2.0.pre.86 • channel master • https://github.com/flutter/flutter.git
Framework • revision dde2044 (12 hours ago) • 2020-10-20 00:59:56 -0400
Engine • revision ea2aea1
Tools • Dart 2.11.0 (build 2.11.0-234.0.dev)