Recently I switched back to using Neovim after being a VSCode user for a while. One of the things I miss in VSCode is the session management that comes bundled in. My brain became wired to doing things like code <projectDir> to open the editor with all files loaded just like the way I left them. Luckily in Vim, you can use :mksession to create sessions.

The Problem

Just like VSCode, I want Neovim to save the session file under the project root directory. Specifically in .nvim/session.vim. I want Neovim to detect whether the opened file is a directory, and based on that, load the session file if exists. Before exiting Neovim, save the session file under the project root directory.

You see, I tried different plugins including persistence.nvim, persisted.nvim, auto-session, sessions.nvim, and project.nvim. None of them achieved what I wanted.

How?

Neovim supports sessions. You can use :mksession to create session files, and :source <file> or nvim -S <file> to restore a session. And with the sessionoptions option, we can tell Neovim exactly what to save in the session file. Simple just like that. Pairing that with autocmds on startup and exit we can get what we want. Read more about this :h session.

The Config

First, we need to tell Neovim what to save in the session file. We do so using the sessionoptions option. In your init.lua add the list of session options you want to save and restore:

vim.opt.sessionoptions = "buffers,curdir,folds,help,tabpages,winsize,winpos,terminal,localoptions"

Here I’m choosing almost everything 🙂 Make sure to avoid adding options to the list since it will interfere with other plugins you might have. Read more about this :h sessionoptions.

Now, we need to add out autocmds on VimEnter and VimLeave.

-- Simple session management on directory open
-- Here we check if the opened file is a directory.
-- Then we load the sessionfile if exists.
-- Set a global flag to save session later.
-- And lastly, we delete the extra directory buffer.
vim.api.nvim_create_autocmd("VimEnter", {
  callback = function(data)
    -- buffer is a directory
    local isdirectory = vim.fn.isdirectory(data.file) == 1
    if not isdirectory then
      return
    end

    -- save session before exit
    vim.g.save_session = false

    -- check if directory is a project directory
    for _, root in ipairs({ ".git", ".hg", ".bzr", ".svn" }) do
      if vim.fn.isdirectory(data.file .. "/" .. root) == 1 then
        vim.g.save_session = true
        break
      end
    end

    if vim.g.save_session then
      -- source session.vim if it exists
      local sessionfile = vim.fn.resolve(data.file .. "/.nvim/session.vim")
      if vim.fn.filereadable(sessionfile) == 1 then
        vim.cmd("source " .. sessionfile)
      end
    end

    -- wipe the directory buffer
    vim.cmd("bw " .. data.buf)
  end,
  nested = true,
})

-- Check if we are in the project root.
-- If we are, save the session file.
vim.api.nvim_create_autocmd("VimLeave", {
  callback = function(data)
    -- only save session if vim started on a directory
    if not vim.g.save_session then
      return
    end

    local sessionfile = ".nvim/session.vim"
    if vim.v.this_session ~= "" then
      sessionfile = vim.v.this_session
    end

    vim.fn.mkdir(".nvim", "p")
    vim.cmd("mksession! " .. sessionfile)
  end,
})

Bonus

When using git, it can be annoying to see the .nvim directory in every project you have. You can ignore the file by adding it to a ~/.gitignore and exclude the file contents from git.

echo '.nvim' >> '~/.gitignore'
git config --global core.excludesFile '~/.gitignore'

That’s it, hope this helps 😃.