GSoC: Neovim over SSH

[siddhantdev]

The current plan for making :connect work with ssh://address is to connect to address with SSH, start Neovim on the remote and tunnel the server socket to a local socket. Then the current UI client can connect to this local socket with :connect, thus allowing editing on the remote computer.

The problem that this faces is that making that SSH connection requires use of vim.fn.jobstart() with either the pty or the term options to effectively take input from the user and neither of those options allows detach. As a result of this, when the local Neovim server is stopped a SIGHUP signal is sent to the job and the SSH connection is closed as well which stops the remote client.

There are two possibilities that have been discussed till now (on Matrix). They are:

1. Wrap the SSH job in something like setsid, which effectively adds a detach like option to jobstart with pty.
2. Explicitly disable connect! for SSH addresses because connect! stops the background Neovim server. One problem this could face is that if there are more clients connected to the server and one of them close it, the SSH job will still be stopped.

I think option 2 is better because it is a lot simpler as option 1 will require OS specific handling and has the potential to get messy. connect ssh://address will connect to the address and then detach from the neovim server. The detached server can continue running in the background, maintaining the ssh tunnel.

vim.fn.jobstart() is required because vim.system currently does not have any way of using pty to interact with the running program which is necessary here.

Ref:
#34257

[justinmk]

making that SSH connection requires use of vim.fn.jobstart() with either the pty or the term options to effectively take input from the user and neither of those options allows detach.

why? ssh does not need to run as a terminal (ssh -t ?), we just need a tunnel to the remote nvim server's socket.

2. Explicitly disable connect! for SSH addresses because connect!

Just ignore this for now. It's more important to just get something actually working.