"diff" is not exectuable (Windows | Neovim nightly)

[ninbura]

issue

When triggering UndotreeToggle in Neovim nightly on Windows I get the following error:

E5108: Error executing lua: function undotree#UndotreeToggle[11]..<SNR>45_new[2]..41, line 6: Vim(echoerr):"diff" is not executable.
stack traceback:                                                                                                                                                                                                                                                                                                                                                                                  [C]: at 0x7ff649ab50c0

This only happens on Windows when running running the nightly build of Neovim. I don't get this error when running the same configuration via Neovim stable (v0.9.5) on Windows, or Neovim stable/nightly on Ubuntu.

I see that others have mentioned this error in another issue. I've also seen discussion of this issue on the neovim subreddit. But their solution is not applicable in this case, as I set PowerShell 7 as my terminal (:h powershell); where diff is a valid command. As mentioned before, undotree works fine using diff in Neovim stable on Windows via the same configuration.

setting powershell as default shell

if(vim.loop.os_uname().sysname == "Windows_NT")
  then
    vim.opt.shell = vim.fn.executable "pwsh" and "pwsh" or "powershell"
    vim.opt.shellcmdflag = "-NoLogo -ExecutionPolicy RemoteSigned -Command [Console]::InputEncoding=[Console]::OutputEncoding=[System.Text.UTF8Encoding]::new();$PSDefaultParameterValues[''Out-File:Encoding'']=''utf8'';Remove-Alias -Force -ErrorAction SilentlyContinue tee;"
    vim.opt.shellredir = "2>&1 | %%{ '$_' } | Out-File %s; exit $LastExitCode"
    vim.opt.shellpipe = "2>&1 | %%{ '$_' } | tee %s; exit $LastExitCode"
    vim.opt.shellquote = ""
    vim.opt.shellxquote = ""
  end

lazy config

return {
  "mbbill/undotree",
  keys = {
    {
      "<leader>u",
      vim.cmd.UndotreeToggle,
      desc = "toggle undotree view"
    }
  }
}

system info

# windows os build
22631.3007

# neovim version
v0.10.0-dev-2074+g786089013

[mbbill]

the plugin requires diff.exe for the diff panel to work. If you don't have the tool under %PATH% you may simply turn off the diff panel by default. Usually the diff.exe comes with the official vim installation, but I'm not sure about neovim. It's fairly easy to just borrow the exe if needed.

[ninbura]

Guess I was just trying to avoid installing another application to get my configuration working remotely. It seems based on Vim's license I can just host their diff.exe myself and pull it to a consistent location.

I guess Neovim stable accounts for diff.exe somehow. Whatever the case, after adding diff.exe to my PATH environment variable I don't get errors in Neovim nightly.

[samisalreadytaken]

diff.exe was removed in nvim releases here neovim/neovim#22802.

To fix this, either put the latest diff.exe release in your vim bin directory

curl -LO https://github.com/neovim/deps/raw/21c5e8bdda33521a6ed497b315e03265a2785cbc/opt/diff.exe

or direct the command to WSL with a script like this

@ECHO OFF
SETLOCAL ENABLEDELAYEDEXPANSION

REM Expects 2 parameters that are full Windows paths `DRIVE:PATH`
REM Converts drive letter to lower case, fixes path separators and checks /mnt/drive/path on WSL

SET ARG1=%~1
SET ARG2=%~2

SET DRIVE1=%ARG1:~0,1%
SET PATH1=%ARG1:~2%

SET DRIVE2=%ARG2:~0,1%
SET PATH2=%ARG2:~2%

SET PATH1=!PATH1:\=/!
SET PATH2=!PATH2:\=/!

for %%C IN (a b c d e f g h i j k l m n o p q r s t u v w x y z) DO (
	SET DRIVE1=!DRIVE1:%%C=%%C!
	SET DRIVE2=!DRIVE2:%%C=%%C!
)

wsl -e diff "/mnt/%DRIVE1%%PATH1%" "/mnt/%DRIVE2%%PATH2%"

let g:undotree_DiffCommand="diff" where diff.bat lives in your PATH. Naming this script to anything else requires #170.

[inaciorafael]

Here is my solution on windows

• Create and download diff.exe
  cd your_nvim_path
mdkir bin
cd bin
curl -LO https://github.com/neovim/deps/raw/21c5e8bdda33521a6ed497b315e03265a2785cbc/opt/diff.exe

Configure diff.exe in your options

-- my_nvim_path/lua/options.lua
if vim.fn.has "win32" == 1 then -- only windows
  vim.g.undotree_DiffCommand = "my_nvim_path/lua/bin/diff.exe"
end

This worked for me!