Failed to archiving flake: ... file has an unsupported type

[nyarly]

I'm building a flake for an web application. For development and testing purposes, I have a Unix socket file in the development environment, and it's configured to be ignored by git:

>  git check-ignore -v devsupport/db_sockets/.s.PGSQL.5432
devsupport/.gitignore:2:db_sockets/*    devsupport/db_sockets/.s.PGSQL.5432

However, when I start Neovim with my flake.nix loaded, I'm asked if I want to fetch things for the archive. That runs for a bit and then:

LSP[nil_ls] Failed to archiving flake: `nix flake archive path:[...]` failed with exit status: 1. Stderr:
error:
       … while fetching the input 'path:[...]'

       error: file '[...]/devsupport/db_sockets/.s.PGSQL.5432' has an unsupported type

([...] elisions are mine)

nix flake ignores this file, because git does. Why does nil try to fetch and then complain that it's a socket?

[oxalica]

I guess it's because Nix does not respect gitignore giving path:[...]. Probably we should prefer git+file:[...] if it is in a Git repository, but I'm not sure if sub-directory works for it.