File tree integration with nvim-tree and NERDTree

[zwhitchcox]

This enables file tree integration with nvim-tree and NERDTree.

It is fairly difficult to get sessions and file tree browsers to play nicely together, but when you do, the result is spectacular.

As such, I thought I'd make it easier to integrate the two with a simple configuration option:

require 'nvim-tree'.setup {
  auto_session_enable_file_tree_integration = true,
}

This hopefully fixes:

• changing directories from nvim-tree not recognized - With Workaround #178
• Unexpected behaviour when opening session with nvim-tree #50

And would be a solution for people struggling with sessions/file trees elsewhere as well:

• Error detected while processing BufLeave Auto commands for "NERD_tree_*" preservim/nerdtree#745
• NERDtree doesn't play well with Vim sessions preservim/nerdtree#337
• Conflitcs with :mksession nvim-tree/nvim-tree.lua#309
• Session conflict when setting buffer name nvim-tree/nvim-tree.lua#591
• Blank nvim-tree when opening a session from Startify/Dashboard - session related nvim-tree/nvim-tree.lua#488
• Session Restore Problems nvim-tree/nvim-tree.lua#296

[rmagatti]

Hey @zwhitchcox, thanks for the PR! I appreciate you trying to fix this!

However, I still have a pretty strong view on adding code into auto-session to support/interface with specific plugins, like I mention in this comment: #105 (comment)

Ultimately adding this code would mean I have to support a whole new set of functionality for interfacing with plugins I don't even personally use myself.

While I can certainly understand the appeal of "just fixing it here", the long-term support of this is what worries me.

[zwhitchcox]

@rmagatti Hey, thanks for getting back to me so quickly. I actually think you're right. You don't want external plugin-specific code in your code, because then if they change something, it could break your code.

I had hoped there would be a file-tree generalized approach, but I can't see one. Oh well.

Instead, I think I can make a auto-session-nvim-tree plugin that can handle the nvim-tree-specific stuff.

Anyway, I took out all the external plugin-specific stuff and left in general bug fixes which prevent the "hook" solution from working. (causing session corruption, infinite loops, etc.)

Let me know if this looks good, and I'll squash the commits.

[zwhitchcox]

This approach was causing an infinite loop. From the docs:

DirChanged After the current-directory was changed.
...
Non-recursive (event cannot trigger itself).

By triggering Autosession.AutoRestoreSession asynchronously, it caused an infinite loop where the opened buffer could change the global directory (somehow) after opening. So, I moved the asynchronous part to after the session was restored. It then runs filetype detect on all the open buffers which fixes the syntax highlighting error.

[zwhitchcox]

This is what fixes the syntax highlighting. I moved it to after the restore session, so that it's always triggered. Although, I'm not sure if the problem exists other than in during the autocmd callbacks? So, it might be better to move it back there if not.

[rmagatti]

Interesting, I hadn't noticed problems with this. But this should be fine anyway 👍

[zwhitchcox]

Ok, I created a plugin auto-session-nvim-tree to your plugin, but those changes depend on this PR.

Please review the code and let me know what you think if you don't mind.

[zwhitchcox]

Ok, I actually just realized there's a SessionLoadPost autocmd, so maybe I can use that which would make it compatible with all session loads, not just this library.

That's not really directly relevant to this PR, but more for the plugin.

SessionLoadPost			After loading the session file created using
				the [:mksession](https://neovim.io/doc/user/starting.html#%3Amksession) command.

This PR will still need to be merged though, because the aforementioned issue will still break, just wanted to let you know.

[rmagatti]

Thanks for putting the time into this! 🎉

[rmagatti]

Interesting, I hadn't noticed problems with this. But this should be fine anyway 👍

[zwhitchcox]

Yeah, happy to help!

So, upon further inspection, it looks like if you add localoptions to your session options:

vim.o.sessionoptions="blank,buffers,curdir,folds,tabpages,winsize,winpos,terminal,localoptions"

this will automatically restore syntax highlighting without needing to redetect the filetype. So, we could probably remove the filetype detect code and just make a note for people to save localoptions in the README. Do you want me to make a PR to this effect?

this also saves options like wrap and number

@rmagatti