Folds are calculated before the tree-sitter tree is updated

[Bekaboo]

Problem

Same as #14977.

If using treesitter as fold provider, foldcolumn can be out of sync after the buffer is changed.

Steps to reproduce

1. Create the minimal.lua init file:

   local tmp = vim.env.TMPDIR
     or vim.env.TEMPDIR
     or vim.env.TMP
     or vim.env.TEMP
     or '/tmp'
   local data = tmp .. '/' .. (vim.env.NVIM_APPNAME or 'nvim')
   local packages_root = data .. '/site'
   local cloned_root = packages_root .. '/pack/packages/start'
   local cloned_path = cloned_root .. '/nvim-treesitter'
   local url = 'https://github.com/nvim-treesitter/nvim-treesitter.git'
   
   vim.fn.mkdir(cloned_root, 'p')
   vim.opt.pp:prepend(packages_root)
   vim.opt.rtp:prepend(packages_root)
   
   if not vim.loop.fs_stat(cloned_path) then
     vim.fn.system({ 'git', 'clone', url, cloned_path })
   end
   
   require('nvim-treesitter.configs').setup({
     ensure_installed = 'json',
     highlight = { enable = true },
   })
   
   vim.o.foldcolumn = '1'
   vim.o.foldmethod = 'expr'
   vim.o.foldexpr = 'nvim_treesitter#foldexpr()'
   vim.o.foldlevelstart = 99

2. Create the following json file test.json for testing:

   {
     "glossary": {
       "title": "example glossary",
       "GlossDiv": {
         "title": "S",
         "GlossList": {
           "GlossEntry": {
             "ID": "SGML",
             "SortAs": "SGML",
             "GlossTerm": "Standard Generalized Markup Language",
             "Acronym": "SGML",
             "Abbrev": "ISO 8879:1986",
             "GlossDef": {
               "para": "A meta-markup language, used to create markup languages such as DocBook.",
               "GlossSeeAlso": [
                 "GML",
                 "XML"
               ]
             },
             "GlossSee": "markup"
           }
         }
       }
     }
   }

3. nvim --clean -u minimal.lua test.json

4. zjzj to jump to the first line of the second fold

5. O to insert a line above

6. Observe that the foldcolumn is out of sync

Screenshots:

• Step 3:

  

• Step 4:

  

• Step 5 (observe that foldcolumn not updated in time):

  

Expected behavior

Foldcolumn should always be in sync.
Foldcolumn should be re-calculated after treesitter updates folds.

Neovim version (nvim -v)

NVIM v0.10.0-dev-1427+gac353e87aec

Vim (not Nvim) behaves the same?

no, vim does not have treesitter

Operating system/version

Linux 6.1.60-1-lts

Terminal name/version

alacritty 0.12.3 (5efb0690) + tmux 3.3a

$TERM environment variable

tmux-256color

Installation

AUR

[lucario387]

Only when using o or O the foldexpr is calculated incorrectly. If instead we use A<CR> it will be correct.

Edit: I was wrong. nnoremap o A<CR> works as expected

[tomtomjhj]

This might have been fixed by recent fixes in vim.treesitter.foldexpr() and extmark updates. Can you still reproduce on the latest version with vim.treesitter.foldexpr() instead of nvim_treesitter#foldexpr()?

[igorlfs]

I can confirm I'm still having this issue with NVIM v0.10.0-dev-3116+gc1396afa7c

EDIT: actually, I'm having a similar issue: given a closed fold, if I use o in its line, it opens. And similarly, when using O in the line below it, it also opens. I had assumed those were the same issue, but my foldcolumn behaves as expected.

[tomtomjhj]

@igorlfs #28709 should fix the issue you're experiencing.

I can't reproduce the original issue Bekaboo described.

[igorlfs]

Hey, thanks for the quick fix! I thought about reporting it, but I suspected it was just a side effect of this issue!