ERROR Invalid plugin spec { "" }

[nbari]

I just upgrade to latest 11.9.1 but now every time I open nvim I get this error:

 ERROR Invalid plugin spec { "" }

This is the output of :checkhealth lazy:

lazy: require("lazy.health").check()

lazy.nvim ~
- {lazy.nvim} version `11.9.1`
- OK {git} `version 2.45.2`
- OK no existing packages found by other package managers
- OK packer_compiled.lua not found
- ERROR Issues were reported when loading your specs:
- ERROR Invalid plugin spec { "" }

luarocks ~
- checking `luarocks` installation
- OK no plugins require `luarocks`, so you can ignore any warnings below
- OK {luarocks} `/usr/bin/luarocks 3.11.1`
- OK {lua5.1} `Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio`

My config of nvim is:
init.lua:

require("user.options")
require("user.keymaps")
require("user.lsp-diagnostic")
require("user.lazy")
require("user.commands")

-- load the color scheme
vim.cmd.colorscheme("kanagawa")

And lua/users/lazy:

-- Bootstrap lazy.nvim
local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
    vim.fn.system({
        "git",
        "clone",
        "--filter=blob:none",
        "https://github.com/folke/lazy.nvim.git",
        "--branch=stable", -- latest stable release
        lazypath
    })
end
vim.opt.rtp:prepend(lazypath)

local lazy_status, lazy = pcall(require, "lazy")
if not lazy_status then
    vim.notify("lazy.nvim not found", vim.log.levels.WARN, {})
    return
end

lazy.setup("user.plugins")

Any ideas ?

[folke]

That's because you literally have an empty string somewhere in a list of specs

[nbari]

Thanks I removed all and found that I had just.lua with this:

return {
    "NoahTheDuke/vim-just",
    ft = {
        "just"
    },
    vim.cmd [[
        au filetype just setlocal shiftwidth=2
    ]]
}

Could you please show me what could be the best way to fix it ? (was working with previous versions)

[nbari]

This seems to fix the problem:

local M = {
    "NoahTheDuke/vim-just",
    ft = {
        "just"
    }
}

M.config = function()
    vim.cmd [[
        au filetype just setlocal shiftwidth=2
    ]]
end

return M

But don't understand why, seems that the config is mandatory in where I can call the vim.cmd ...

[folke]

return {
    "NoahTheDuke/vim-just",
    ft = {
        "just"
    },
    init = function()
        vim.cmd [[
             au filetype just setlocal shiftwidth=2
         ]]
   end
}