Make automatic installation script in wiki tips compatible with Neovim

[clebs]

When using the snippet to auto install everything on Neovim it does not recognise PlugInstall as a command without restarting.
To solve this I added one line to the suggested tip to source Plug right after downloading it.

It now looks as follows (in lua):

local data_dir = fn.stdpath('data')
if vim.fn.empty(vim.fn.glob(data_dir .. '/site/autoload/plug.vim')) == 1 then
	vim.cmd('silent !curl -fLo ' ..
		data_dir ..
		'/site/autoload/plug.vim --create-dirs  https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim')
	vim.cmd('source ' .. data_dir .. '/site/autoload/plug.vim')
	vim.cmd('autocmd VimEnter * PlugInstall --sync | source $MYVIMRC')
end

Would it be possible to add this solution for those who get the error that PlugInstall is not a command on first setup with this tip?

NVIM v0.9.5
Build type: Release
LuaJIT 2.1.1703358377

• Type:
  • Bug
  • Enhancement
  • Feature Request
  • Question
• OS:
  • All/Other
  • Linux
  • macOS
  • Windows
• Vim:
  • Terminal Vim
  • GVim
  • Neovim

[jtmr05]

I've faced this issue as well and this does solve it.

[junegunn]

Any idea why the command is not recognized?

Because plug.vim is in autoload directory, the file is automatically loaded when you call any of its plug#... functions. Your configuration file should have both plug#begin and plug#end so they will trigger the load then you have :PlugInstall command. autocmd VimEnter is triggered after Vim finished processing the configuration file, so at that point, :PlugInstall must be available.

I have tested the code without the source line in this init.lua file and it works just fine.

local data_dir = vim.fn.stdpath('data')
if vim.fn.empty(vim.fn.glob(data_dir .. '/site/autoload/plug.vim')) == 1 then
	vim.cmd('silent !curl -fLo ' ..
		data_dir ..
		'/site/autoload/plug.vim --create-dirs  https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim')
	vim.cmd('autocmd VimEnter * PlugInstall --sync | source $MYVIMRC')
end

local vim = vim
local Plug = vim.fn['plug#']

vim.call('plug#begin')
Plug('junegunn/vim-easy-align')
vim.call('plug#end')

[clebs]

That is interesting, I do have a plug#begin/end block right after what I just pasted exactly as you wrote. Yet without sourcing it explicitly, I do get the mentioned error. This behaviour is also consistent between MacOS and Linux.

Might be something specific to neovim? I have not tried with regular vim.

[jtmr05]

With regular vim there seems to be no issue

[mamekoro]

I ran into the same problem with Neovim 0.9.5 and init.vim (not init.lua), but OP solved it.

This script works as expected;

" Automatic installation of vim-plug
let s:data_dir = stdpath('data') . '/site'
if empty(glob(s:data_dir . '/autoload/plug.vim'))
  silent execute '!curl -fL --create-dirs '
    \. '-o ' . s:data_dir . '/autoload/plug.vim '
    \. 'https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim'
  execute 'source ' . s:data_dir . '/autoload/plug.vim'
  autocmd VimEnter * PlugInstall --sync | source $MYVIMRC
endif

---

@junegunn Could you retry in a fresh environment?
This problem occurs on the first run as the OP mentioned.

it does not recognise PlugInstall as a command without restarting.

I tried your init.lua with Neovim 0.9.5 in a new Docker container, and got this error;

Error detected while processing /home/rust/.config/nvim/init.lua:
E5113: Error while calling lua chunk: Vim:E117: Unknown function: plug#begin
stack traceback:
        [C]: in function 'call'
        /home/rust/.config/nvim/init.lua:12: in main chunk
Error detected while processing VimEnter Autocommands for "*":
E492: Not an editor command: PlugInstall --sync | source $MYVIMRC
Press ENTER or type command to continue

[junegunn]

Okay, after removing all the directories related to Neovim, I was able to reproduce the problem, and it seems like a bug of Neovim.

The gist of the problem is this: Neovim does not pick up autoload files if ~/.local/share/nvim/site directory was not present when it was started.

rm -rf ~/.config/nvim ~/.local/share/nvim
mkdir -p ~/.config/nvim # ~/.local/share/nvim/site # FIXME: uncomment this part
cat << "EOF" > ~/.config/nvim/init.vim
call mkdir(stdpath('data') . '/site/autoload', 'p')
call writefile(['function! foobar#it()', 'echom 123', 'endfunction'], stdpath('data') . '/site/autoload/foobar.vim')
call foobar#it()
EOF
nvim

E117: Unknown function: foobar#it
Press ENTER or type command to continue

However, if we create the directory before starting Neovim, the autoload script is loaded as expected and prints 123.

rm -rf ~/.config/nvim ~/.local/share/nvim
mkdir -p ~/.config/nvim ~/.local/share/nvim/site # NOTE: uncommented
cat << "EOF" > ~/.config/nvim/init.vim
call mkdir(stdpath('data') . '/site/autoload', 'p')
call writefile(['function! foobar#it()', 'echom 123', 'endfunction'], stdpath('data') . '/site/autoload/foobar.vim')
call foobar#it()
EOF
nvim

I don't know if this is intentional, but I wouldn't call this a feature. Maybe they were trying to speed up processing by remembering which directories existed, so they could ignore non-existent directories afterwards.

Anyway, manually sourcing the plug.vim file seems to be the only workaround we can think of now. But this can't really be an ideal solution, because other autoload functions are also unavailable during the start-up.

rm -rf ~/.config/nvim ~/.local/share/nvim
mkdir -p ~/.config/nvim # ~/.local/share/nvim/site
cat << "EOF" > ~/.config/nvim/init.vim
call mkdir(stdpath('data') . '/site/autoload', 'p')
call writefile(['function! foobar#it()', 'echom 123', 'endfunction'], stdpath('data') . '/site/autoload/foobar.vim')
call writefile(['function! barfoo#it()', 'echom 456', 'endfunction'], stdpath('data') . '/site/autoload/barfoo.vim')
source ~/.local/share/nvim/site/autoload/foobar.vim
call foobar#it() " This works
call barfoo#it() " This doesn't
EOF
nvim

E117: Unknown function: barfoo#it

But after Neovim starts, call barfoo#it() works.

[clebs]

That is an interesting finding. Will report it there and see what the answer is: neovim/neovim#28128

Thanks for the detailed analysis!