fix(vim.system): env=nil passes env=nil to uv.spawn

731e616a79 made it so passing `{env = nil, clear_env = true }` would
pass `{env = {}}` to `vim.uv.spawn`.

However this is not what `clear_env` is (arguably) supposed to do.
If `env=nil` then that implies the uses wants `vim.uv.spawn()` to use
the default environment. Adding `clear_env = true` simply prevents
`NVIM` (the base environment) from being added.

Fixes #34730

1 files changed, 7 insertions, 2 deletions

diff --git a/runtime/lua/vim/_system.lua b/runtime/lua/vim/_system.lua
index 38e348bc03..ced341fe28 100644
--- a/runtime/lua/vim/_system.lua
+++ b/runtime/lua/vim/_system.lua
@@ -208,13 +208,18 @@ end
 --- @param clear_env? boolean
 --- @return string[]?
 local function setup_env(env, clear_env)
+  if not env and clear_env then
+    return
+  end
+
+  env = env or {}
   if not clear_env then
     --- @type table<string,string|number>
-    env = vim.tbl_extend('force', base_env(), env or {})
+    env = vim.tbl_extend('force', base_env(), env)
   end
 
   local renv = {} --- @type string[]
-  for k, v in pairs(env or {}) do
+  for k, v in pairs(env) do
     renv[#renv + 1] = string.format('%s=%s', k, tostring(v))
   end