roslyn-lsp --stdio option

[seblj]

Summary

We just got support for a named pipe from a client to connect to the server, and it seems from the other issue that you would be open to a PR for a stdio option as well. I thought I would open an issue about stdio for tracking potential progress on this

Background and Motivation

I am maintaining a plugin for roslyn support in neovim, and it would really simplify my solution if stdio support is added

Proposed Feature

Support --stdio flag when starting the server

Context

I am considering looking into this myself, but I thought I would add a tracking issue first so if someone else beats me to it, they could post a comment here or link a PR to this issue :)

[jasonmalinowski]

Just one general caveat about this request: since Roslyn loads code we don't own (like analyzers, source generators, etc.) it's always possible that somebody might write to stdout in a way we can't prevent. #76437 right now discusses redirecting Console.Out -- which is a good idea, don't get me wrong -- but that still won't prevent anybody doing shenanigans and directly grabbing the file handle. I Really, Really, Really™ hope nobody is doing that in the wild, but just be aware it's always possible for your LSP stream to get broken.

[CyrusNajmabadi]

That's already doc'ed as disallowed. Roslyn extensions are not allowed to perform IO of any kind. This follows that model.

[jasonmalinowski]

Yes, on paper it's disallowed. Just letting @seblj not to be too surprised when in a year or two they find some customer using some analyzer doing the bad thing. 😄