BUG: `get_scrolled_off_node_text` will break if no tree is created for the current tabpage

[ngpong]

Did you check docs and existing issues?

• I have read all the docs.
• I have searched the existing issues.
• I have searched the existing discussions.

Neovim Version (nvim -v)

NVIM v0.10.0-dev

Operating System / Version

wsl2 ubuntu-22.04

Describe the Bug

Hi guys, I found some errors when opening a new tabpage inside neo-tree (in my case a new tabpage of DiffView).

Here is the reproduce steps:

reproduce steps

_neovim.2023-06-30.00-36-56.mp4

Here is the captured stacktrace:

stacktrace

E5108: Error executing lua .../packer/start/neo-tree.nvim/lua/neo-tree/ui/selector.lua:224: attempt to index field 'tree' (a nil value)
stack traceback:
        .../packer/start/neo-tree.nvim/lua/neo-tree/ui/selector.lua:224: in function 'get_scrolled_off_node_text'
        .../packer/start/neo-tree.nvim/lua/neo-tree/ui/selector.lua:237: in function <.../packer/start/neo-tree.nvim/lua/neo-tree/ui/selector.lua:228>

The break occurs within the get_scrolled_off_node_text function, and the reason for the break is that state does not contain the tree member. After some deeper digging, I found that the reason is because the current tabpage(from vim.api.nvim_get_current_win) does not create a neo-tree when get_state_for_window is called.

Normally the require'neo-tree.ui.selector'.get() would be called from a created neo-tree tabpage. But in my case, when I opened the DiffView, it was probably some asynchronous initialization had not yet completed that caused this exception.

In my opinion, maybe we should add some checks to get_scrolled_off_node_text to enhance the robustness of the function, so that we can better catch exceptions that don't match our expectations.

So, I tried to do some small tests and try to fix this problem, which modified like this:

M.get_scrolled_off_node_text = function(state)
+ if state.tree == nil then
+   return
+ end
  -- ....
end

This modification solves my problem. If you think this modification is positive, can you try to let me to fix it? I really like this plugin and would like to give some modest contribution. Otherwise, I would be willing and active to work with you to find out the deeper reasons for this problem.

Screenshots, Traceback

No response

Steps to Reproduce

Please see the trackback and video in description.

Expected Behavior

No breaks when opening diffview

Your Configuration

Just use the default settings, but set source_selector.winbar and source_selector.show_scrolled_off_parent_node to true.

I will add it in time if you think this is necessary.

[pynappo]

Realized nobody responded to this for 2 years, sorry about that

You're good to submit a pr with that fix. Otherwise i'll just commit the fix you suggested.