fix(deps): respect special GIT_xxx env vars that affecting Git actions

Details:
- Environment variables `GIT_DIR` and `GIT_WORK_TREE` can affect any Git
  operation that is meant to be done inside specific Git repo.
  They need to be manually handled in 'mini.deps' for any Git action it
  want to do.

Resolve #1968

Co-authored-by: Diego Velez <diego.velez.dev@gmail.com>

Author: echasnovski

lua/mini/deps.lua

@@ -1489,7 +1489,12 @@ H.cli_run = function(jobs)
     -- Prepare data for `vim.loop.spawn`
     local executable, args = command[1], vim.list_slice(command, 2, #command)
     local process, stdout, stderr = nil, vim.loop.new_pipe(), vim.loop.new_pipe()
-    local spawn_opts = { args = args, cwd = cwd, stdio = { nil, stdout, stderr } }
+
+    -- - Unset special `GIT_xxx` variables that can affect `git` commands
+    local env = vim.fn.environ()
+    env.GIT_DIR, env.GIT_WORK_TREE = nil, nil
+
+    local spawn_opts = { args = args, cwd = cwd, env = env, clear_env = true, stdio = { nil, stdout, stderr } }
 
     local on_exit = function(code)
       -- Process only not already closing job

tests/test_deps.lua

@@ -85,6 +85,11 @@ local mock_timestamp = function(timestamp)
   child.lua(lua_cmd)
 end
 
+local mock_bad_env_vars = function()
+  child.fn.setenv('GIT_DIR', test_dir_absolute .. '/.git')
+  child.fn.setenv('GIT_WORK_TREE', test_dir_absolute)
+end
+
 local mock_hide_path = function(path)
   path = path or test_dir_absolute
   -- NOTE: use "^" as pattern separator because "/" can cause troubles
@@ -103,6 +108,10 @@ local get_spawn_log = function() return child.lua_get('_G.spawn_log') end
 local validate_git_spawn_log = function(ref_log)
   local spawn_log = get_spawn_log()
 
+  local ref_env = child.fn.environ()
+  -- Should never include environment variables that can affect Git operations
+  ref_env.GIT_DIR, ref_env.GIT_WORK_TREE = nil, nil
+
   local n = math.max(#spawn_log, #ref_log)
   for i = 1, n do
     local real, ref = spawn_log[i], ref_log[i]
@@ -114,23 +123,25 @@ local validate_git_spawn_log = function(ref_log)
       -- Assume default `git` options
       local args = { '-c', 'gc.auto=0' }
       vim.list_extend(args, ref)
-      eq(real, { executable = 'git', options = { args = args, cwd = real.options.cwd } })
+      local opts = { args = args, cwd = real.options.cwd, env = ref_env, clear_env = true }
+      local ref_val = { executable = 'git', options = opts }
+      eq(real, ref_val)
     else
       local opts = vim.deepcopy(ref)
       -- Assume default `git` options
       local args = { '-c', 'gc.auto=0' }
       opts.args = vim.list_extend(args, opts.args)
+      if opts.env == nil then
+        opts.env = opts.env or ref_env
+        opts.clear_env = true
+      end
       eq(real, { executable = 'git', options = opts })
     end
   end
 end
 
-local clear_spawn_log = function() child.lua('_G.spawn_log = {}') end
-
 local get_process_log = function() return child.lua_get('_G.process_log') end
 
-local clear_process_log = function() child.lua('_G.process_log = {}') end
-
 -- Work with notifications
 local mock_notify = function()
   child.lua([[
@@ -541,6 +552,9 @@ T['add()']['Install'] = new_set({
 })
 
 T['add()']['Install']['works'] = function()
+  mock_bad_env_vars()
+  local ref_environ = child.fn.environ()
+
   child.lua([[
     _G.stdio_queue = {
       { out = 'git version 2.43.0'}, -- Check Git executable
@@ -596,6 +610,9 @@ T['add()']['Install']['works'] = function()
     { '(mini.deps) (1/1) Installed `new_plugin`', 'INFO' },
   }
   validate_notifications(ref_notify_log)
+
+  -- Should not affect any environment variables
+  eq(child.fn.environ(), ref_environ)
 end
 
 T['add()']['Install']['checks for executable Git'] = function()
@@ -1222,6 +1239,8 @@ local update = forward_lua('MiniDeps.update')
 
 T['update()']['works'] = function()
   child.set_size(40, 80)
+  mock_bad_env_vars()
+  local ref_environ = child.fn.environ()
 
   -- By default should update all plugins in session
   add('plugin_1')
@@ -1310,6 +1329,9 @@ T['update()']['works'] = function()
   mock_hide_path(test_dir_absolute)
   child.expect_screenshot()
   validate_confirm_buf('confirm-update')
+
+  -- Should not affect any environment variables
+  eq(child.fn.environ(), ref_environ)
 end
 
 T['update()']['checks for executable Git'] = function()
@@ -1371,6 +1393,9 @@ T['update()']['Confirm buffer'] = new_set({
 })
 
 T['update()']['Confirm buffer']['can apply changes'] = function()
+  mock_bad_env_vars()
+  local ref_environ = child.fn.environ()
+
   -- Should run `update()` on buffer write with only valid plugin names
   -- Remove 'plugin_1' from being updated
   child.cmd('g/^+++ plugin_1/normal! dd/')
@@ -1379,6 +1404,9 @@ T['update()']['Confirm buffer']['can apply changes'] = function()
   -- Should update and close confirmation buffer
   eq(child.lua_get('_G.update_args'), { { 'plugin_2' }, { force = true, offline = true } })
   validate_not_confirm_buf()
+
+  -- Should not affect any environment variables
+  eq(child.fn.environ(), ref_environ)
 end
 
 T['update()']['Confirm buffer']['can cancel'] = function()