How to get the current path of a neo-tree buffer?

[wookayin]

I would like to get the path of an existing neo-tree buffer (i.e., the path of the root node) programatically. Or any node/item the current cursor is pointing to? The path to the root node is main concern; FYI nerd-tree allows to do this like b:NERDTree.root.path._str().

I searched the documentation for "current path" or looked into b: variables but I was unable to find them quickly. Any help, hints, or documentation?

[cseickel]

If you use the bind_to_cwd option, which is true by default, then a sidebar tree's root will be the same as the tab working directory. A tree opened in a window with the "current" position will use the local working directory of that window.

Alternatively, you can read the state of a tree with:

local state = require("neo-tree.sources.manager").get_state("filesystem")
print(state.path)

That will give you the state of the "filesystem" sidebar in the current tab. The parameters to the get_state function are: source_name, tabnr, winid

If you want to get the state for a particular window that is not a sidebar, pass the window id:

local winid = vim.api.nvim_get_current_win()
local state = require("neo-tree.sources.manager").get_state("filesystem", nil, winid)
print(state.path)

[ryanmsnyder]

Thanks @cseickel. I'm using it to display info in my statusline about the current file/directory under my cursor in neo-tree. When I toggle neo-tree on the first time, get_node() works perfectly. If I then close neo-tree and then re-open it, I get an error:

E5108: Error executing lua .../.local/share/neovim/lazy/nui.nvim/lua/nui/tree/init.lua:279: Invalid 'window': Expected Lua
number
stack traceback:
        [C]: in function 'nvim_win_get_cursor'
        .../.local/share/neovim/lazy/nui.nvim/lua/nui/tree/init.lua:279: in function 'get_node'

After some debugging, it appears nui's get_node function is passing the previous neo-tree bufnr to vim.fn.win_findbuf(bufnr). Since the previous bufnr no longer exists, it's not able to find the correct window id of the buffer.

As an example, when I start up neovim and toggle neo-tree on, the bufnr is 15 and I don't get the error - everything works as expected. When I toggle neo-tree off and then back on, I get the error because nui is passing a bufnr of 15 to vim.fn.win_findbuf(bufnr), which now doesn't exist because neo-tree's bufnr is now 16.

Any idea why this error doesn't occur on the first toggling on of neo-tree but then occurs on subsequent toggles of neo-tree?

[cseickel]

My guess is that you have captured an old tree variable and are trying to reuse it later instead of getting the current one. Show me the code and I'll tell you what is wrong.

[ryanmsnyder]

I was actually able to ignore the error with a protected call because even though it throws an error, it still works. Like I mentioned above, on the 2nd time (or more) of toggling neo-tree on, it calls vim.fn.win_findbuf(bufnr) with the old bufnr once. What I didn't mention though is that it immediately calls it again right after with the correct bufnr.

Here's my code. I'm using heirline for my statusline. The below is a component in my statusline:

local FileSize = {
  provider = function()
    local neo_tree_utils = require "neo-tree.utils"
    local state = require("neo-tree.sources.manager").get_state "filesystem"

    if state.tree ~= nil then
      local success, node = pcall(function()
        return state.tree:get_node() -- where the error occurs 🛑
      end)

      if success then
        local text = "-"
        if node.type == "file" then
          local stat = neo_tree_utils.get_stat(node)
          local size = stat and stat.size or nil
          if size then
            local size_success, human = pcall(neo_tree_utils.human_size, size)
            if size_success then
              text = human or text
            end
          end

          return text
          -- return node.path
        end
      end
    end
  end,
}

The above component is a child component of the parent component below, which is only active if the filetype is of type neo-tree:

local NeoTreeStatusLine = {
  condition = function()
    return conditions.buffer_matches {
      filetype = { "neo%-tree" },
    }
  end,

  ViMode,
  Space,
  FileSize,
  Align,
  WorkDirNameBlock,
}

Let me know if you need to see more code. I would rather fix the error than catch it but I suppose it's not urgent since it still works as expected. Thanks for your help.

[cseickel]

The problem there @ryanmsnyder is that the status line refreshes constantly, so you are actually catching it in the middle of being rendered when there is a tree but not yet a valid buffer. The pcall is fine, but if you want to be more precise there is a method that will tell you if the window is actually fully ready to be interacted with:

local ready = require("neo-tree.ui.renderer").window_exists(state)

[ryanmsnyder]

Thanks for the response. I checked if ready == true right before calling state.tree:get_node() but I'm still getting the same error.

[wookayin]

Thanks! I find the latter one more general approach that subsumes the former one, but the latter doesn't work with the neotree opened in the left panel.

More specifically, when neo-tree is on a left sidebar require("neo-tree.sources.manager").get_state("filesystem", nil, winid).path returns NIL, where winid refers to the correct neo-tree window. This should cover both cases, right?

[cseickel]

More specifically, when neo-tree is on a left sidebar require("neo-tree.sources.manager").get_state("filesystem", nil, winid).path returns NIL, where winid refers to the correct neo-tree window. This should cover both cases, right?

No, it shouldn't. Maybe it would be cleaner if there were separate methods but I never really intended for that method to be used externally. There are 2 different types of trees:

1. Sidebar style, which is one per tab, identified by the tab number
2. Netrw style, which is one per window, identified by the window id

The get_state() function will return a tab state if the last argument is nil, or a window state if the last argument is not nil. In the case of a tab state, it is identified by the tab it belongs to and not the window. This roughly follows the convention of vim's getcwd(), albeit in reverse order. The reason for this is historic, in the beginning there was only sidebars and therefor all state was identified by the tab number.

If what you want is the state of a sidebar in the current tab, just use this:

require("neo-tree.sources.manager").get_state("filesystem")

[wookayin]

require("neo-tree.sources.manager").get_state("filesystem", nil, winid) does not have path property where winid is the window id on the "netrw" style. When winid = nil (the sidebar style), path is retrieved correctly. Would this be a bug (v2.60)?

[cseickel]

@wookayin The path property will not be set until after the first navigation. My guess is that you are retrieving the state before the window has been shown, or you are calling the function with the wrong winid and getting a brand new state for the wrong window.