public async Task <Connection?> ActivateAsync(CancellationToken cancellationToken)
{
// HACK HACK HACK: prevent potential crashes/state corruption during load. Fixes
// https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1261421
//
// When we create an LSP server, we compute our server capabilities; this may depend on
// reading things like workspace options which will force us to initialize our option persisters.
// Unfortunately some of our option persisters currently assert they are first created on the UI
// thread. If the first time they're created is because of LSP initialization, we might end up loading
// them on a background thread which will throw exceptions and then prevent them from being created
// again later.
//
// The correct fix for this is to fix the threading violations in the option persister code;
// asserting a MEF component is constructed on the foreground thread is never allowed, but alas it's
// done there. Fixing that isn't difficult but comes with some risk I don't want to take for 16.9;
// instead we'll just compute our capabilities here on the UI thread to ensure everything is loaded.
// We _could_ consider doing a SwitchToMainThreadAsync in InProcLanguageServer.InitializeAsync
// (where the problematic call to GetCapabilites is), but that call is invoked across the StreamJsonRpc
// link where it's unclear if VS Threading rules apply. By doing this here, we are dong it in a
// VS API that is following VS Threading rules, and it also ensures that the preereqs are loaded
// prior to any RPC calls being made.
//
// https://github.com/dotnet/roslyn/issues/29602 will track removing this hack
// since that's the primary offending persister that needs to be addressed.
await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
_ = GetCapabilities();
if (_languageServer is not null)
{
Contract.ThrowIfFalse(
_languageServer.HasShutdownStarted,
"The language server has not yet been asked to shutdown."
);
await _languageServer.DisposeAsync().ConfigureAwait(false);
}
var(clientStream, serverStream) = FullDuplexStream.CreatePair();
_languageServer = await InProcLanguageServer
.CreateAsync(
this,
serverStream,
serverStream,
_requestDispatcherFactory.CreateRequestDispatcher(),
Workspace,
_diagnosticService,
_listenerProvider,
_lspWorkspaceRegistrationService,
_asyncServiceProvider,
_diagnosticsClientName,
cancellationToken
)
.ConfigureAwait(false);
return(new Connection(clientStream, clientStream));
}
public async Task <Connection> ActivateAsync(CancellationToken cancellationToken)
{
if (_languageServer is not null)
{
Contract.ThrowIfFalse(_languageServer.HasShutdownStarted, "The language server has not yet been asked to shutdown.");
await _languageServer.DisposeAsync().ConfigureAwait(false);
}
var(clientStream, serverStream) = FullDuplexStream.CreatePair();
_languageServer = new InProcLanguageServer(
this,
serverStream,
serverStream,
_requestDispatcherFactory.CreateRequestDispatcher(),
Workspace,
_diagnosticService,
_listenerProvider,
_lspWorkspaceRegistrationService,
clientName: _diagnosticsClientName);
return(new Connection(clientStream, clientStream));
}