Very poor performance after “do not use vim.treesitter.highlighter”

[amarshall]

Description

I am seeing huge performance regressions on some files (usually large ones or those with a lot of nesting) on current master (b8d1ffe). I have bisected this to 4f5c742, before that change (or reverting it) the problem goes away.

Neovim version

v0.9.5

Expected behavior

No lag upon context change or appearance

Actual behavior

Intolerable lag

Minimal config

local plugins = {
  ts         = 'https://github.com/nvim-treesitter/nvim-treesitter',
  ts_context = 'https://github.com/nvim-treesitter/nvim-treesitter-context',
  -- ADD ADDITIONAL PLUGINS THAT ARE _NECESSARY_ TO REPRODUCE THE ISSUE
}

for name, url in pairs(plugins) do
  local install_path = '/tmp/nvim/site/'..name
  if vim.fn.isdirectory(install_path) == 0 then
    vim.fn.system { 'git', 'clone', '--depth=1', url, install_path }
  end
  vim.o.runtimepath = install_path..','..vim.o.runtimepath
end

-- ADD INIT.LUA SETTINGS THAT IS _NECESSARY_ FOR REPRODUCING THE ISSUE

Steps to reproduce

1. nvim --clean -u minimal.lua with some file (I used this file)
2. :TSContextEnable
3. Press M to move cursor to the middle (so context appears)
4. Scroll enough to get some context
5. Press H to move the cursor to the top (so context disappears)
6. Press M and experience lag for cursor movement and context reappearing (does not occur with :TSContextDisable)

Also occurs when scrolling through and the context is visible and needs to change.

[colin969]

The lag is easily half a second plus for a few thousand line file.

Definitely a deal-breaker, hopefully it'll be a relatively quick fix.

[romgrk]

I have reverted the commit for now.