Flutter service extensions disabled after a hot-restart

[elliette]

I noticed that if you start a test with a connection to a live app, trigger a hot-restart, and then try to call a service extension from Flutter, the test will fail because the service extension is never re-registered.

I'm pretty sure this is the same underlying cause as #7313, when DWDS was connecting directly to the VM Service URI instead of the DDS URI.

Because DDS intercepts the streamListen request and sends back all of the service extensions it is aware of, these service extensions are never sent back to the DevTools test infra VM service connection.

Here is the code we will likely need to modify (where we get the VM service URI and connect to it):

devtools/packages/devtools_app/test/test_infra/flutter_test_driver.dart

Lines 327 to 358 in 9bd0125

	final debugPort =
	await waitFor(event: 'app.debugPort', timeout: appStartTimeout);
	final Map<String, dynamic> params = debugPort['params'];
	final String wsUriString = params['wsUri'];
	_vmServiceWsUri = Uri.parse(wsUriString);
	// Map to WS URI.
	_vmServiceWsUri =
	convertToWebSocketUrl(serviceProtocolUrl: _vmServiceWsUri);
	vmService = await vmServiceConnectUriWithFactory<VmServiceWrapper>(
	_vmServiceWsUri.toString(),
	vmServiceFactory: ({
	// ignore: avoid-dynamic, mirrors types of [VmServiceFactory].
	required Stream<dynamic> /*String|List<int>*/ inStream,
	required void Function(String message) writeMessage,
	Log? log,
	DisposeHandler? disposeHandler,
	Future? streamClosed,
	String? wsUri,
	bool trackFutures = false,
	}) =>
	VmServiceWrapper.defaultFactory(
	inStream: inStream,
	writeMessage: writeMessage,
	log: log,
	disposeHandler: disposeHandler,
	streamClosed: streamClosed,
	wsUri: wsUri,
	trackFutures: true,
	),
	);

@bkonyi Do you happen to know how we could get the DDS URI here instead? Thanks!

[kenzieschmoll]

This may not be just a testing only issue. I noticed that the Performance Overlay button on the performance page becomes disabled after a hot restart, indicating that we are not getting the service extension event registered event after a hot restart is performed.

[elliette]

I just saw this too, not while running tests. This seems to be more widespread - we are losing the Flutter service extensions after a hot-restart.

[elliette]

If I run an app with --no-dds, the Flutter service extensions are re-registered on hot-restart.

[bkonyi]

Just to clarify, service extensions registered using dart:developer don't actually result in ServiceRegistered events being sent on the Service stream, but ServiceExtensionAdded events on the Isolate stream.

[elliette]

I haven't been able to reproduce this anymore. I'm lowering this to P2, but if I encounter it again I will investigate more.