[Bug] [^2.4.0] DriftIsolate - cannot connect from background isolate

[wryczko]

Hi,

I believe version 2.4.0 introduced a bug when trying to establish a connection using DriftIsolate from within background isolate (using workmanager). Here is code sample:

var driftIsolate = await _ensureDriftIsolate();
var connection = await driftIsolate.connect();
var database = DriftContext.connect(connection); <= app hangs here, but only in background isolate (it works in foreground)

 // this is the new constructor
 DriftContext.connect(DatabaseConnection connection) : super.connect(connection); // I know it has been changed in v2.5.0

Future<DriftIsolate> _ensureDriftIsolate() async {
  final dir = await getApplicationDocumentsDirectory();
  final path = p.join(dir.path, 'filename.sqlite');

  var driftPort = IsolateNameServer.lookupPortByName("somePortName");
  if (driftPort == null) {
    final receivePort = ReceivePort();
    IsolateNameServer.registerPortWithName(receivePort.sendPort, driftPortName);
    await Isolate.spawn(_startBackground, _IsolateStartRequest(receivePort.sendPort, path));

    final firstMessage = await receivePort.first;

    driftPort = firstMessage as SendPort;
  }

  return DriftIsolate.fromConnectPort(driftPort);
}

void _startBackground(_IsolateStartRequest request) {
  final driftIsolate = DriftIsolate.inCurrent(() => DatabaseConnection(LazyDatabase(() async {
        setupSqlCipher();

        final file = File(request.targetPath);
        return NativeDatabase(file, logStatements: false, setup: (rawDb) {
          assert(_debugCheckHasCipher(rawDb));
          rawDb.execute("PRAGMA key = 'secretPassword';");
        });
      })));

  // inform the starting isolate about this, so that it can call .connect()
  request.sendDriftIsolate.send(driftIsolate.connectPort);
}

Everything works in version 2.3.0

Regards

[simolus3]

Thanks for the report! I've tried to reproduce this in the repro-2319 branch in this directory. Unfortunately I couldn't quite get the setup to work - it seems like the isolate name server is not shared between the foreground isolate and workmanager - it spawns a new drift isolate each time, but otherwise works.

Could you provide more information on how to reproduce this (maybe fork this repository and finish the repro in that branch)?

[kuhnroyal]

This only works if the background isolate is started in the same VM. Something might have changed in the workmanager library.

[dickermoshe]

There has been no activity in this issue for over a year and no reproducible bug exists.