Error with which_key when telescope window width is narrow (no preview showing)

[prurph]

Description

If my terminal window is sufficiently narrow such that the preview isn't showing (i.e. it's below defaults.layout_config.horizontal.preview_cutoff), invoking telescope.actions.which_key results in the error below. Simply resizing the window such that the telescope preview is displayed makes everything work properly.

E5108: Error executing lua ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:962: Expected Lua number
stack traceback:
        [C]: in function 'nvim_win_get_position'
        ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:962: in function 'win_central_row'
        ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:968: in function 'run_replace_or_original'
        ...k/packer/opt/telescope.nvim/lua/telescope/actions/mt.lua:30: in function 'key_func'
        ...ack/packer/opt/telescope.nvim/lua/telescope/mappings.lua:236: in function 'execute_keymap'
        [string ":lua"]:1: in main chunk

Neovim version

NVIM v0.7.0-dev+855-ge41e8b3fd
Build type: Release
LuaJIT 2.1.0-beta3

Operating system and version

macOS 12.1

checkhealth telescope

2 telescope: require("telescope.health").check()
   3 ========================================================================
   4 ## Checking for required plugins
   5   - OK: plenary installed.
   6   - OK: nvim-treesitter installed.
   7
   8 ## Checking external dependencies
   9   - OK: rg: found ripgrep 13.0.0
  10   - OK: fd: found fd 8.3.1
  11
  12 ## ===== Installed extensions =====
  13
  14 ## Telescope Extension: `smart_history`
  15   - INFO: No healthcheck provided
  16
  17 ## Telescope Extension: `terms`
  18   - INFO: No healthcheck provided
  19
  20 ## Telescope Extension: `themes`
  21   - INFO: No healthcheck provided

Steps to reproduce

1. Bind telescope which_key.
2. Shrink terminal window width sufficiently such that telescope preview window is not shown
3. Activate telescope and then activate which_key

Expected behavior

Key shortcuts are displayed

Actual behavior

An error occurs:

E5108: Error executing lua ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:962: Expected Lua number
stack traceback:
        [C]: in function 'nvim_win_get_position'
        ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:962: in function 'win_central_row'
        ...packer/opt/telescope.nvim/lua/telescope/actions/init.lua:968: in function 'run_replace_or_original'
        ...k/packer/opt/telescope.nvim/lua/telescope/actions/mt.lua:30: in function 'key_func'
        ...ack/packer/opt/telescope.nvim/lua/telescope/mappings.lua:236: in function 'execute_keymap'
        [string ":lua"]:1: in main chunk

Minimal config

vim.cmd [[set runtimepath=$VIMRUNTIME]]
vim.cmd [[set packpath=/tmp/nvim/site]]
local package_root = '/tmp/nvim/site/pack'
local install_path = package_root .. '/packer/start/packer.nvim'
local function load_plugins()
  require('packer').startup {
    {
      'wbthomason/packer.nvim',
      {
        'nvim-telescope/telescope.nvim',
        requires = {
          'nvim-lua/plenary.nvim',
          { 'nvim-telescope/telescope-fzf-native.nvim', run = 'make' },
        },
      },
      -- 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
_G.load_config = function()
  require('telescope').setup()
  require('telescope').load_extension('fzf')
  -- ADD INIT.LUA SETTINGS THAT ARE _NECESSARY_ FOR REPRODUCING THE ISSUE
end
if vim.fn.isdirectory(install_path) == 0 then
  print("Installing Telescope 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 load_config()]]