You can then add execute 'PackerInstall' after packed line. That should work.

Thank your @cloggier, I have tried this way before. But since packer.nvim is not sourced, no PackerInstall command can be found, unless I exit vim and open vim again manually.

You can use packadd packer.nvim to ensure that packer is sourced. It's probably also best to run PackerSync rather than PackerInstall to ensure that your compiled file gets correctly constructed.

To clarify: you'll want the execute PackerSync command after your call to packer.startup (assuming you're using the startup method), as that's what creates those commands.

Hi @wbthomason , do you mean add a extract line like this?

I have tried this before. It will cause a error, which is

Right - that's why I was saying that you need the execute PackerSync after you use packer.startup or similar. Otherwise, the commands will not exist.
e.g.

if not packer_exists then
...
end
require('packer').startup(....)
if not packer_exists then execute 'PackerSync' end

Thank you @wbthomason . Seem that it is a little difficult for me. I wrap packer conf into a lua script and return packer.startup(...) in the last line of the script. I don't known how to run packersync after the return.

One of the attempts,

https://github.com/yech1990/myneovim.lua/tree/b0b9b3f067d8e4ea8f2e7c2a86d28596f3c037fb

Did you find a solution ? I have the same problem.

Hey, I know this question is old, but I was having the same problem and I solved it doing the following steps:

• Remove your plugin folder from your nvim root folder.
• Reinstall Packer
  Packer is installed at that location ~/.local/share/nvim/site/pack/packer/start/packer.nvim, just remove it and install it again.
• Now, open the lua file where Packer is being used to install plugins and run the editor command :so %

Now, you might be able to run commands like PackerSync for installing your packages.

That's how I solved it, hope you guys can solve it too.