`OptionSet` event is triggered when opening the tree

[tummetott]

Description

Hello,

I registered an autocmd on the OptionSet event with pattern = "cursorline" and noticed that nvim-tree triggers that event when opening the tree. The expected behaviour is that no events are triggered when setting an option.

Nvim has the ex command :noautocmd <cmd> which would supress that events are fired. However I'm not aware of an LUA API call with the same effect.

nvim-tree sets the cursorline here:

nvim-tree.lua/lua/nvim-tree/view.lua

Line 130 in 7944e47

vim.opt_local[k] = v

A possible fix would be:

-- Create a temporary wrapper function
function _G.tmp()
    vim.opt_local[k] = v 
end

-- Fire the wrapper function from vimscript with `noautocmd`
vim.cmd('noautocmd call v:lua.tmp()')

-- Delete the wrapper function
_G.tmp = nil

This workaround is not very elegant but I can't think of a better way since :noautocmd only existst as ex-command

However I'm not sure if that has any sideeffects in general. I greped the repo for the OptionSet event and could not find anything. So I guess nvim-tree does not rely on events triggerd by setlocal, so I guess this change should be fine

Neovim version

NVIM v0.8.1
Build type: Release
LuaJIT 2.1.0-beta3

Operating system and version

macOS 10.15.7

nvim-tree version

16f2806

Minimal config

vim.cmd [[set runtimepath=$VIMRUNTIME]]
vim.cmd [[set packpath=/tmp/nvt-min/site]]
local package_root = "/tmp/nvt-min/site/pack"
local install_path = package_root .. "/packer/start/packer.nvim"
local function load_plugins()
  require("packer").startup {
    {
      "wbthomason/packer.nvim",
      "nvim-tree/nvim-tree.lua",
      "nvim-tree/nvim-web-devicons",
      -- ADD PLUGINS THAT ARE _NECESSARY_ FOR REPRODUCING THE ISSUE
    },
    config = {
      package_root = package_root,
      compile_path = install_path .. "/plugin/packer_compiled.lua",
      display = { non_interactive = true },
    },
  }
end
if vim.fn.isdirectory(install_path) == 0 then
  print "Installing nvim-tree and dependencies."
  vim.fn.system { "git", "clone", "--depth=1", "https://github.com/wbthomason/packer.nvim", install_path }
end
load_plugins()
require("packer").sync()
vim.cmd [[autocmd User PackerComplete ++once echo "Ready!" | lua setup()]]
vim.opt.termguicolors = true
vim.opt.cursorline = true

-- MODIFY NVIM-TREE SETTINGS THAT ARE _NECESSARY_ FOR REPRODUCING THE ISSUE
_G.setup = function()
  require("nvim-tree").setup {}
end

local autocmd = vim.api.nvim_create_autocmd
local augroup = vim.api.nvim_create_augroup

local group = augroup('Test', { clear = true })
autocmd('OptionSet', {
    pattern = 'cursorline',
    callback = function()
        print('set cursorline option triggered')
    end,
    group = group,
})

Steps to reproduce

1. nvim -nu /tmp/nvt-min.lua
2. :NvimTreeOpen
3. :messages
4. Investigate output

Expected behavior

The event should not be triggered

Actual behavior

The event is triggered

[alex-courtis]

We have precedent for using an ex command for this sort of thing:

nvim-tree.lua/lua/nvim-tree.lua

Line 211 in 9e87ee2

vim.cmd "noautocmd wincmd p"

There is an alternative: temporarily using eventignore:

nvim-tree.lua/lua/nvim-tree/actions/node/open-file.lua

Line 198 in d85b671

local eventignore = vim.opt.eventignore:get()

Telescope does a similar thing:
https://github.com/nvim-telescope/telescope.nvim/blob/053f2303c4fac5c45a56b9de0a7481b7db94d6ba/lua/telescope/utils.lua#L417

I'd be grateful if you tried out that solution and raised a PR. I'd be happy if you ignored OptionSet for all buffer locals in this case