Lock ordering deadlock in TableDataSource

[sharwell]

🔗 This is the root cause of AB#1296045

The following code takes two locks in order:

roslyn/src/VisualStudio/Core/Def/Implementation/TableDataSource/AbstractTableDataSource.cs

Lines 200 to 205 in 275f4c7

	lock (_gate)
	{
	snapshot = _subscriptions;
	GetOrCreateFactory_NoLock(data, out var factory, out var newFactory);
	factory.OnDataAddedOrChanged(data);

roslyn/src/VisualStudio/Core/Def/Implementation/TableDataSource/TableEntriesFactory.cs

Line 84 in 275f4c7

lock (_gate)

The following code takes the same two locks in opposite order:

roslyn/src/VisualStudio/Core/Def/Implementation/TableDataSource/TableEntriesFactory.cs

Lines 48 to 56 in 275f4c7

	lock (_gate)
	{
	var version = _lastVersion;
	if (TryGetLastSnapshot(version, out var lastSnapshot))
	{
	return lastSnapshot;
	}
	var items = _entriesSources.GetItems();

roslyn/src/VisualStudio/Core/Def/Implementation/TableDataSource/AbstractTableDataSource.cs

Line 295 in 275f4c7

lock (_gate)

[lindexi]

See https://developercommunity.visualstudio.com/t/VisualStudio-no-response-when-debugging/1377004

[CyrusNajmabadi]

@heejaechang Do you have any idea what the right thing is to do here. I'm afraid i don't know much about how the table-data-source is structured.

[CyrusNajmabadi]

Will be addressed once we move to pull diagnostics.