In my post last month I thought I had fixed this issue but turns out I did not. The actual fix to stop getting this error:

5108: Error executing lua [string "v:lua"]:1: attempt to call global 'dropbar' (a nil value)
stack traceback:
        [string "v:lua"]:1: in main chunk

bat /home/haseeb/.local/share/nixCats-nvim/sessions/%2Fhome%2Fhaseeb%2Fprojects%2Fvoxicle.vim | rg dropbar
setlocal winbar=%{%v:lua.dropbar()%}
setlocal winbar=%{%v:lua.dropbar()%}
setlocal winbar=%{%v:lua.dropbar()%}

We want the winbar to nil. The fix that worked for me was this:

vim.o.sessionoptions = "blank,buffers,curdir,folds,help,tabpages,winsize,winpos,terminal,localoptions"

require("auto-session").setup({
	pre_save_cmds = {
		function()
			vim.cmd([[
                noautocmd windo set winbar=
                noautocmd windo setlocal winbar=
            ]])
		end,
	},
})

I recently moved to dropbar from barbecue as it has been archived and kept getting a weird error for buffer open when I would reopen Neovim. I use the auto-session plugin, which loads back the previous state of NixVim when I last exited in that folder, i.e. open buffers.

E5108: Error executing lua [string "v:lua"]:1: attempt to call global 'dropbar' (a nil value)
stack traceback:
        [string "v:lua"]:1: in main chunk

I noticed though I would only get this error the second time I would open Neovim, which then made think maybe it was an issue with auto-session. So I looked at the serialised file it generates so it knows what to load when we open Neovim again. Which I found at:

nvim /home/haseeb/.local/share/nvim/sessions/%2Fhome%2Fhaseeb%2Fprojects%2Fvoxicle.vim

One line in there looked like this:

setlocal winbar=%{%v:lua.dropbar()%}

So I removed this line by updating my config:

require("auto-session").setup({
	pre_save_cmds = {
		function()
			vim.opt.winbar = nil -- Clear winbar before saving session
		end,
	},
})

This stopped the error from occurring, as there is no winbar line now. I am not a 100% what was happening, but it seems it was running this line before dropbar had loaded. I am using nixCats. Anyway, that’s it! That should resolve the issues.