vm_service getInstances fails with null reference when invoked for TypeParameters

[polina-c]

Dart code:

  var classes = await connection.service.getClassList(isolateId).map(
        (classRef) => _ItemInIsolate(
          itemId: classRef.id!,
          isolateId: isolateId,
          name: classRef.name,
        ),
      );


  for (final theClass in classes) {
    const pathLengthLimit = 10000000;
    print('requesting getInstances for ${theClass.name}');
    final instances = (await connection.service.getInstances(
          theClass.isolateId,
          theClass.itemId,
          pathLengthLimit,
        ))

Error:

Connecting to VM Service at ws://127.0.0.1:50630/kCipO3f91uk=/ws
requesting getInstances for Class
requesting getInstances for PatchClass
requesting getInstances for Function
requesting getInstances for TypeParameters
type 'Null' is not a subtype of type 'ObjRef'
dart:core                                       new List.from
package:vm_service/src/vm_service.dart 6594:17  new InstanceSet._fromJson
package:vm_service/src/vm_service.dart 6579:41  InstanceSet.parse
package:vm_service/src/vm_service.dart 70:25    createServiceObject
package:vm_service/src/vm_service.dart 2588:26  VmService._processResponse
package:vm_service/src/vm_service.dart 2567:7   VmService._processMessageStr
package:vm_service/src/vm_service.dart 2519:7   VmService._processMessage

flutter --version
Flutter 3.12.0-15.0.pre.57 • channel master • [email protected]:flutter/flutter.git
Framework • revision 3ec96a8a4a (8 hours ago) • 2023-07-09 08:57:27 -0400
Engine • revision 111051e4f5
Tools • Dart 3.1.0 (build 3.1.0-285.0.dev) • DevTools 2.25.0

[a-siva]

//cc @derekxu16

[a-siva]

TypeParameters are returned as _TypeParameters by the VM and in pkg:vm_service we don't account for that, see https://github.com/dart-lang/sdk/blob/main/pkg/vm_service/lib/src/vm_service.dart#L192

[bkonyi]

We should just go ahead and make _TypeParameters public, I don't see any reason why we shouldn't. When we do make this public, we'll need to make sure we update DevTools to handle this since the object inspector probably has explicit support for the private type.

[rmacnak-google]

pkg:vm_service acts as if it were public :(

https://dart-review.googlesource.com/c/sdk/+/316862

[bkonyi]

pkg:vm_service acts as if it were public :(

https://dart-review.googlesource.com/c/sdk/+/316862

That's unfortunate... :( Thanks for the quick fix!

[derekxu16]

I just published package:vm_service 11.9.0, which includes @rmacnak-google's fixes.

https://pub.dev/packages/vm_service/versions/11.9.0