Confusion over ensure_installed mechanism

[skiss9]

I'm setting up a minimal nvim config using lazy.nvim but not LazyVim. I need prettier.

I looked at how LazyVim was doing it and tried to use:

{
  "williamboman/mason.nvim",
  opts = { ensure_installed = { "prettier" } }
}

That would install mason but not prettier. I tried to track down where this ensure_installed property was run, and couldn't find references in mason, nor in lazy.nvim. Only in LazyVim, mason-lsp and treesitter.

Are there some implicit plugin dependencies required to have this ensure_installed property honored? Is this just ad-hoc code I shouldn't try to duplicate?

I ended up doing this which works fine:

  {
    "williamboman/mason.nvim",
    config = function()
      require("mason").setup()
      local registry = require("mason-registry")
      if not registry.is_installed("prettier") then
        registry.get_package("prettier"):install()
      end
    end
  },

Other question, is there anything that prevents lazy.nvim from installing prettier? Why do we need 2 package managers?

Thanks in advance for the clarifications!

[dpetka2001]

Mason does not have a ensure_installed property by default. LazyVim just creates an internal table ensure_installed in Mason opts and then in config function it uses it to iterate over that table and install packages using the Mason API. Relevant code here.

[skiss9]

Thanks for the clarification. Are there any plans to improve lazy.nvim so it can install plugins like treesitter out of the box without requiring LazyVim?

[skiss9]

And is the mason dependency here to stay or is the plan for lazy.nvim to take on the installation features that currently require mason?

[dpetka2001]

lazy.nvim is a package manager used not only by LazyVim, but by other Neovim distros (AstroNvim, NvCahd, kickstart etc) and even by many people who write their own custom configs from scratch. So you can do whatever you want with it as long as you write the configuration you want. It doesn't have to be LazyVim. Installing plugins out of the box is out of scope for a plugin manager (at least in my personal opinion as a simple user, i'm not speaking on behalf of the maintainer). That's the role of a Neovim distro or custom personal configuration.

PS: for your second question i doubt lazy.nvim will do the same as Mason.