Troubleshooting Nvim-CMP Configuration with Lazy.nvim

[Patxi080]

Hello! I'm trying to set up nvim-cmp with its default autocompletion options, but I'm running into some trouble.
I've been following the nvim-cmp documentation on GitHub, which provides the following default configuration using vim-plug:

call plug#begin(s:plug_dir)
Plug 'neovim/nvim-lspconfig'
Plug 'hrsh7th/cmp-nvim-lsp'
Plug 'hrsh7th/cmp-buffer'
Plug 'hrsh7th/cmp-path'
Plug 'hrsh7th/cmp-cmdline'
Plug 'hrsh7th/nvim-cmp'

" For vsnip users.
Plug 'hrsh7th/cmp-vsnip'
Plug 'hrsh7th/vim-vsnip'

" For luasnip users.
" Plug 'L3MON4D3/LuaSnip'
" Plug 'saadparwaiz1/cmp_luasnip'

" For mini.snippets users.
" Plug 'echasnovski/mini.snippets'
" Plug 'abeldekat/cmp-mini-snippets'

" For ultisnips users.
" Plug 'SirVer/ultisnips'
" Plug 'quangnguyen30192/cmp-nvim-ultisnips'

" For snippy users.
" Plug 'dcampos/nvim-snippy'
" Plug 'dcampos/cmp-snippy'

call plug#end()

lua <<EOF
  -- Set up nvim-cmp.
  local cmp = require'cmp'

  cmp.setup({
    snippet = {
      -- REQUIRED - you must specify a snippet engine
      expand = function(args)
        vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
        -- require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
        -- require('snippy').expand_snippet(args.body) -- For `snippy` users.
        -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
        -- vim.snippet.expand(args.body) -- For native neovim snippets (Neovim v0.10+)

        -- For `mini.snippets` users:
        -- local insert = MiniSnippets.config.expand.insert or MiniSnippets.default_insert
        -- insert({ body = args.body }) -- Insert at cursor
        -- cmp.resubscribe({ "TextChangedI", "TextChangedP" })
        -- require("cmp.config").set_onetime({ sources = {} })
      end,
    },
    window = {
      -- completion = cmp.config.window.bordered(),
      -- documentation = cmp.config.window.bordered(),
    },
    mapping = cmp.mapping.preset.insert({
      ['<C-b>'] = cmp.mapping.scroll_docs(-4),
      ['<C-f>'] = cmp.mapping.scroll_docs(4),
      ['<C-Space>'] = cmp.mapping.complete(),
      ['<C-e>'] = cmp.mapping.abort(),
      ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
    }),
    sources = cmp.config.sources({
      { name = 'nvim_lsp' },
      { name = 'vsnip' }, -- For vsnip users.
      -- { name = 'luasnip' }, -- For luasnip users.
      -- { name = 'ultisnips' }, -- For ultisnips users.
      -- { name = 'snippy' }, -- For snippy users.
    }, {
      { name = 'buffer' },
    })
  })
[...]
EOF

I've translated this configuration to use with Lazy.nvim, specifically opting for luasnip as my snippet engine. Here's my current lazy.nvim configuration for nvim-cmp:

return{
"hrsh7th/nvim-cmp",
dependencies = {
           "neovim/nvim-lspconfig"
           "hrsh7th/cmp-nvim-lsp"
           "hrsh7th/cmp-buffer"
           "hrsh7th/cmp-path"
           "hrsh7th/cmp-cmdline"
            -- For luasnip users.
           "L3MON4D3/LuaSnip"
           "saadparwaiz1/cmp_luasnip"
    },
    opts =  function()
                         -- Set up nvim-cmp.
                         local cmp = require('cmp')
                         snippet = {
                               -- REQUIRED - you must specify a snippet engine
                               expand = function(args)
                                         require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
                               end,
                            },
                           window = {
                               completion = cmp.config.window.bordered(),
                               documentation = cmp.config.window.bordered(),
                           },
                          mapping = cmp.mapping.preset.insert({
                                    ['<C-b>'] = cmp.mapping.scroll_docs(-4),
                                    ['<C-f>'] = cmp.mapping.scroll_docs(4),
                                    ['<C-Space>'] = cmp.mapping.complete(),
                                    ['<C-e>'] = cmp.mapping.abort(),
                                    ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
                           }),
                          sources = cmp.config.sources({
                                   { name = 'luasnip' }, -- For luasnip users.
                                   { name = 'nvim_lsp' },
                           }, {
                                   { name = 'buffer' },
                                   })
    end,
}

The issue is that this configuration isn't working but doesn't show any error. My understanding from the lazy.nvim documentation is that if an opts key is present, lazy.nvim will automatically call the setup function for the plugin with the provided opts table, so I suppose that it is not necessary to write require("plugin").setup({opts}) but maybe I am wrong.

Any idea what I am missing?

[abhirath-a]

In your lazy.nvim configuration, you are using opts as a function. I assume this is a function because the cmp variable can be declared. In order for this to work, you have to return a lua table in the opts config. Here's an example:

opts = function()
    -- Set up nvim-cmp.
    local cmp = require("cmp")
    return {
        snippet = {
            -- REQUIRED - you must specify a snippet engine
            expand = function(args)
                require("luasnip").lsp_expand(args.body) -- For `luasnip` users.
            end
        },
        window = {
            completion = cmp.config.window.bordered(),
            documentation = cmp.config.window.bordered()
        },
        mapping = cmp.mapping.preset.insert(
            {
                ["<C-b>"] = cmp.mapping.scroll_docs(-4),
                ["<C-f>"] = cmp.mapping.scroll_docs(4),
                ["<C-Space>"] = cmp.mapping.complete(),
                ["<C-e>"] = cmp.mapping.abort(),
                ["<CR>"] = cmp.mapping.confirm({select = true}) -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
            }
        ),
        sources = cmp.config.sources(
            {
                {name = "luasnip"}, -- For luasnip users.
                {name = "nvim_lsp"}
            },
            {
                {name = "buffer"}
            }
        )
    }
end,