Extremely simple configuration doesn't work (load order)

[grundic]

Hello,

I have started a migration to nvim+lua and decided to move from Plug to Packer as well.
My configuration is located here: https://github.com/grundic/vcsh-neovim-master

I have Packer cloned, the issue seems in the loading order. I would like to clone my configuration and bootstrap it with this command:

$ nvim --headless -c 'autocmd User PackerComplete quitall' -c 'PackerSync'

The problem I have is that the color scheme is not being installed, which leads to this error:

$ nvim --headless -c 'autocmd User PackerComplete quitall' -c 'PackerSync'
Error detected while processing /usr/local/home/cgi/.config/nvim/init.lua:
E5113: Error while calling lua chunk: /usr/local/home/cgi/.config/nvim/lua/settings.lua:48: Vim(colorscheme):E185: Cannot find color scheme 'gruvbox'
stack traceback:
        [C]: in function 'cmd'
        /usr/local/home/cgi/.config/nvim/lua/settings.lua:48: in main chunk
        [C]: in function 'require'
        /usr/local/home/cgi/.config/nvim/init.lua:18: in main chunkError detected while processing command line:
E492: Not an editor command: PackerSync

Here is my ~/.config/nvim/init.lua (simplified):

require('settings')
require('autocommands')
require('plugins')

The setting.lua contains colorsheme selection: cmd [[colorscheme gruvbox]] and the plugins.lua lists a dependency on that colorscheme: use 'morhetz/gruvbox'.

I tried changing the order of require('settings') and require('plugins'), making sure that plugins are first, but it still doesn't work. I haven't found anything related in the documentation.

There were several question, which looks similar, but I don't understand how should I proceed:

• How to ensure packer.startup runs before require("package")? #651
• Should `packer_compiled.lua` be renamed to `__packer_compiled.lua` by default? #565
• https://www.reddit.com/r/neovim/comments/mohogr/neovim_lua_config_cant_install_plugins_when/

Can someone please helm me to fix this problem?
Thank you.

[wbthomason]

I believe that this is a problem only with bootstrapping - the colorscheme loading error seems to prevent the rest of init from running (based on the Not an editor command: PackerSync you also get), which prevents the plugin from being installed. I am a bit surprised that reordering didn't work, but this is probably due to Neovim only checking for colorschemes at start. When you reorder to have plugins first, then run once, then open Neovim again, does the colorscheme load as expected?

As @mjlbach mentioned on Matrix, you can use a trick wherein you set an environment variable to signal that you're in an installation run and skip the parts of the config that rely on yet-uninstalled dependencies. If you only ever use headless Neovim for installs/bootstrapping, a slightly easier version of this trick checks the number of attached UIs (vim.api.nvim_list_uis()).

Another possible workaround is to wrap the cmd call with pcall, which should prevent the error from breaking the later use of PackerSync, and get the plugins to install. I haven't tested this myself, though.

[grundic]

I've come with simple WTR solution:

$ cat <<EOF > simple.lua
print("Test configuration has sucessfully been loaded")
require('packer').startup(function()
  use 'wbthomason/packer.nvim'
  use 'morhetz/gruvbox'
end)

cmd [[colorscheme gruvbox]]
EOF

# make sure the gruvbox is not installed, remove generated cache
$ rm -rf ~/.local/share/nvim/site/pack/packer/start/gruvbox 
$ rm -f ~/.config/nvim/plugin/packer_compiled.lua

# try to start neovim
$ nvim -u simple.lua

Test configuration has sucessfully been loaded
Error detected while processing /usr/local/home/cgi/simple.lua:
E5113: Error while calling lua chunk: simple.lua:11: attempt to call global 'cmd' (a nil value)
stack traceback:
        simple.lua:11: in main chunk
Press ENTER or type command to continue

I tried using pcall(cmd, [[colorscheme gruvbox]]), which works fine. But that means that users have to wrap other potential places with pcall to make sure that it won't fail during initial setup (e.g. all plugins settings have to be wrapped with it).
It might be a limitation of Lua itself, which is unfortunate.

Actually, after wrinthing this I came with an idea:

$  nvim -u .config/nvim/lua/plugins.lua --headless -c 'autocmd User PackerComplete quitall' -c 'PackerSync'

Aaand it worked like a charm 🥳 If all plugin requirements are collected in a single file, we can load it for bootstrap, ignoring all other settings.
@wbthomason, do you think it is a good solution for a given problem?

[wbthomason]

Ah, that's quite clever! I like that - let's add it to the docs.

Also, for future reference: I believe the reason you get the nil global error is because, until you bind it, cmd is not in the global namespace - it's vim.cmd instead.

For most plugin settings, you can use packer's config key feature to specify code that will only run after the plugin is installed and loaded. I didn't recommend this for the colorscheme because some users have reported issues with setting their colorscheme later in their startup (i.e. when packer_compiled is sourced).

[grundic]

Also, for future reference: I believe the reason you get the nil global error is because, until you bind it, cmd is not in the global namespace - it's vim.cmd instead.

Ah, right. In the original script I made an alias local cmd = vim.cmd and forgot about it in the example. Yes, after calling it like vim.cmd I got a proper error

E5113: Error while calling lua chunk: simple.lua:11: Vim(colorscheme):E185: Cannot find color scheme 'gruvbox'

let's add it to the docs.

Sweet, will prepare a PR 🤓