bug: Clobbering GIT_SSH_COMMAND leads to problems

[ixil]

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• I have read all the lazy.nvim docs
• I have searched the existing issues of lazy.nvim
• I have searched the exsiting issues of plugins related to this issue

Neovim version (nvim -v)

NVIM v0.8.3 Build type: RelWithDebInfo LuaJIT 2.1.0-beta3 Features: -acl +iconv +tui

Operating system/version

Windows 11

Describe the bug

Lazy specifies the GIT_SSH_COMMAND env argument, as far as I can tell in order to specify the -oBatchMode flag.
However, I have specified a GIT_SSH (basically equivalent to GIT_SSH_COMMAND for using plink.exe. The current method in lazy.nvim means all git (that uses ssh) commands fail as git cannot get the required keys (that plink provides).

Some solution ideas:

1. Check for if the env-args GIT_SSH_COMMAND / GIT_SSH are set, and if so do not overwrite - however git has the config options core.sshCommand and ssh.variant - though not sure what version of git they were added
2. Don't set, or make it an opt-in to set GIT_SSH_COMMAND - this way users are aware, and make an explicit choice.

IMO, the user should set this behaviour within git's config, rather than the tool - of course it helps to be aware to do it.
When trying to work out why lazy wasn't working for me, looking at the git source, the ssh_command detection / flags are a bit out-of-date, i.e. it does not specify either OpenSSH nor plink with the -BathMode=yes or -batch resepctively, but does explicit ly for tortoiseplink which I believe added -batch before plink. So perhaps the fix is really an issue for upstream git?

For other users with my somewhat esoteric setup, I set ssh.variant tortoiseplink and core.sshCommand to the plink executable within git config

Steps To Reproduce

1. Use windows
2. Configure Git to use plink.exe (putty) put in the env: GIT_SSH = C:\Program Files\PuTTY\plink.exe

Alternatively:

1. Set core.sshCommand to plink executable within git config

Expected Behavior

lazy.nvim to respect the GIT_SSH or GIT_SSH_COMMAND or related config options.

Repro

-- DO NOT change the paths and don't remove the colorscheme
local root = vim.fn.fnamemodify("./.repro", ":p")

-- set stdpaths to use .repro
for _, name in ipairs({ "config", "data", "state", "cache" }) do
  vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. "/" .. name
end

-- bootstrap lazy
local lazypath = root .. "/plugins/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  vim.fn.system({ "git", "clone", "--filter=blob:none", "https://github.com/folke/lazy.nvim.git", lazypath, })
end
vim.opt.runtimepath:prepend(lazypath)

-- install plugins
local plugins = {
  "folke/tokyonight.nvim",
  -- add any other plugins here
}
require("lazy").setup(plugins, {
  root = root .. "/plugins",
})

vim.cmd.colorscheme("tokyonight")
-- add anything else here

[folke]

I don't want to remove the GIT_SSH_COMMAND by default. It would make updating/installing/checking for updates way slower.

Just pushed a change where you can override GIT_SSH_COMMAND.

Just set it like vim.env.GIT_SSH_COMMAND = " " or though other means