Exception when opening DevTools in VS Code

[kenzieschmoll]

 [zoneGuarded]: TypeError: null: type 'minified:Wz' is not a subtype of type 'Map<String, Object?>'
org-dartlang-sdk:///dart-sdk/lib/_internal/js_runtime/lib/js_helper.dart 1209:19  wrapException
org-dartlang-sdk:///dart-sdk/lib/_internal/js_shared/lib/rti.dart 1577:3          _failedAsCheck
org-dartlang-sdk:///dart-sdk/lib/_internal/js_shared/lib/rti.dart 1554:3          _generalAsCheckImplementation
../../../lib/src/service/editor/api_classes.dart 310:35                           EditorClient._initialize.<anonymous function>
org-dartlang-sdk:///dart-sdk/lib/async/zone.dart 1538:46                          _rootRunUnary
org-dartlang-sdk:///dart-sdk/lib/async/zone.dart 1428:34                          _CustomZone.runUnary
org-dartlang-sdk:///dart-sdk/lib/async/zone.dart 1329:7                           _CustomZone.runUnaryGuarded
org-dartlang-sdk:///dart-sdk/lib/async/stream_impl.dart 381:5                     _BufferingStreamSubscription._sendData
org-dartlang-sdk:///dart-sdk/lib/async/stream_impl.dart 573:5                     _DelayedData.perform

Looks like a null error in ActiveLocationChangedEvent: https://github.com/flutter/devtools/blob/master/packages/devtools_app/lib/src/service/editor/api_classes.dart/#L310

Flutter 3.28.0-2.0.pre.38699 • channel [user-branch] • unknown source
Framework • revision d14140f854 (27 hours ago) • 2025-01-13 10:20:40 +1300
Engine • revision d14140f854
Tools • Dart 3.7.0 (build 3.7.0-312.0.dev) • DevTools 2.42.0

My vscode settings:

    // Required for the Property Editor.
    "dart.previewDtdLspIntegration": true,
    "dart.experimentalDtdHandlers": true,
    "dart.experimentalPropertyEditor": true,
    // Optional, ensures that when a property is edited a hot-reload is triggered.
    "dart.flutterHotReloadOnSave": "all",

@DanTup @elliette

[kenzieschmoll]

Confirmed this exception does not occur when I commented out the vs code settings to enable the experimental property editor

[DanTup]

Yeah, looks like a bug in the code linked above. In https://dart-review.googlesource.com/c/sdk/+/392908 we made textDocument nullable (it may have been done after the DevTools code was created?):

  /// An identifier that represents a specific version of a specific document.
  ///
  /// `null` is there is no active document.
  VersionedTextDocumentIdentifier? textDocument;

But in the DevTools code it's not:

devtools/packages/devtools_app/lib/src/service/editor/api_classes.dart

Line 320 in e475ad1

final TextDocument textDocument;

@elliette null is valid here if the active editor is removed - for example if the user closes the last open file they had. Probably the property editor should show some kind of message (like "open a file to use the property editor").

[elliette]

Thanks for bringing this to my attention! Will send out a fix.