Comment # 2 on bug 1202958 from baramba

To reproduce:

1. Use neovim without a config to edit a file with a space:
$ nvim --clean 'test file'

2. Initialize an lsp client in neovim (store the client id in a global var for
future use):
:lua vim.g.my_client_id=vim.lsp.start_client({cmd={'lua-language-server'}})

3. Attach the current buffer to the initialized client:
:lua vim.lsp.buf_attach_client(0, vim.g.my_client_id)

The error should be printed:

E5108: Error executing lua /usr/share/nvim/runtime/lua/vim/uri.lua:44: attempt
to call upvalue 'tohex' (a nil value
)
stack traceback:
        /usr/share/nvim/runtime/lua/vim/uri.lua:44: in function
</usr/share/nvim/runtime/lua/vim/uri.lua:43>
        [C]: in function 'uri_encode'
        /usr/share/nvim/runtime/lua/vim/uri.lua:68: in function
'uri_from_bufnr'
        /usr/share/nvim/runtime/lua/vim/lsp.lua:1234: in function
'buf_attach_client'
        [string ":lua"]:1: in main chunk