I have a question that's somewhat related to the VFS stuff that I have been thinking about (Injecting a custom FileSystem into SourceKit?, https://github.com/apple/swift/pull/24417, https://github.com/marcrasi/swift/pull/1), but I think it's independent enough to deserve its own thread.
We have noticed that if we send "editor.open" requests with file contents to SourceKit, we asynchronously get back "source.notification.compile-did-finish" notifications with diagnostics.
There seems to be nothing in the notification allowing us to associate it back with a particular "editor.open" request, so we can't tell which version of a file's contents the diagnostics refer to.
Is there some way to receive diagnostic information from SourceKit with information about exactly which version of a file it refers to? If not, would it be reasonable to add a feature to SourceKit that allows us to make this association? Maybe allow the client to specify a token with each "editor.open" request, and then pass that token back to the client in "source.notification.compile-did-finish" notification?