on_enter stopped working properly

[hrqmonteiro]

This is a minimal.lua i created:

-- Bootstrap lazy.nvim
local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not (vim.uv or vim.loop).fs_stat(lazypath) then
  local lazyrepo = "https://github.com/folke/lazy.nvim.git"
  local out = vim.fn.system({ "git", "clone", "--filter=blob:none", "--branch=stable", lazyrepo, lazypath })
  if vim.v.shell_error ~= 0 then
    vim.api.nvim_echo({
      { "Failed to clone lazy.nvim:\n", "ErrorMsg" },
      { out, "WarningMsg" },
      { "\nPress any key to exit..." },
    }, true, {})
    vim.fn.getchar()
    os.exit(1)
  end
end
vim.opt.rtp:prepend(lazypath)

-- Make sure to setup `mapleader` and `maplocalleader` before
-- loading lazy.nvim so that mappings are correct.
-- This is also a good place to setup other settings (vim.opt)
vim.g.mapleader = " "
vim.g.maplocalleader = "\\"

local function jfunc()
  if vim.wo.diff then
    return "]c"
  else
  end
  local function _3_()
    return gitsigns.next_hunk()
  end
  vim.schedule(_3_)
  return "<Ignore>"
end

-- Setup lazy.nvim
require("lazy").setup({
  spec = {
	  {
		  "lewis6991/gitsigns.nvim",
		  config = function()
			  require("gitsigns").setup()
		  end
	  },
	  {
		  "nvimtools/hydra.nvim",
		  config = function()
			  local Hydra = require("hydra")
			  local gitsigns = require("gitsigns")

			  Hydra({
				  name = "+git",
				  body = "<leader>gh",
				  config = {
					  buffer = vim.bufnr,
					  color = "red",
					  invoke_on_body = true,
					  -- on_enter = function()
					  --  print("a")
					  -- end
				  },
				  heads = {
					{"J", jfunc, {desc = "next hunk", expr = true}}
				  }
			  })
		  end
	  }
  },
  -- Configure any other settings here. See the documentation for more details.
  -- colorscheme that will be used when installing plugins.
  install = { colorscheme = { "habamax" } },
  -- automatically check for plugin updates
  checker = { enabled = true },
})

And it works properly:

But when trying to pass a function on on_enter (uncommenting that section), it returns this error as soon as i open nvim:

I can't use on_enter or on_exit

[benlubas]

what neovim version?

[hrqmonteiro]

what neovim version?

NVIM v0.10.1
Build type: Release
LuaJIT 2.1.1713484068
Run "nvim -V1 -v" for more info