feat(api): allow win_close in cmdwin to close wins except previous

Disallow closing the previous window from `nvim_win_close`, as this will cause
issues.

Again, no telling how safe this is. It also requires exposing old_curwin. :/

Also note that it's possible for the `&cmdheight` to change if, for example,
there are 2 tabpages and `nvim_win_close` is used to close the last window in
the other tabpage while `&stal` is 1. This is addressed in a later commit.

1 files changed, 10 insertions, 4 deletions

diff --git a/test/functional/api/window_spec.lua b/test/functional/api/window_spec.lua
index e7e767817b..74aaae0c6f 100644
--- a/test/functional/api/window_spec.lua
+++ b/test/functional/api/window_spec.lua
@@ -540,15 +540,21 @@ describe('API/win', function()
       command('split')
       eq(2, #meths.list_wins())
       local oldwin = meths.get_current_win()
+      local otherwin = meths.open_win(0, false, {
+        relative='editor', row=10, col=10, width=10, height=10,
+      })
       -- Open cmdline-window.
       feed('q:')
-      eq(3, #meths.list_wins())
+      eq(4, #meths.list_wins())
       eq(':', funcs.getcmdwintype())
-      -- Vim: not allowed to close other windows from cmdline-window.
+      -- Not allowed to close previous window from cmdline-window.
       eq('E11: Invalid in command-line window; <CR> executes, CTRL-C quits',
-        pcall_err(meths.win_close, oldwin, true))
+         pcall_err(meths.win_close, oldwin, true))
+      -- Closing other windows is fine.
+      meths.win_close(otherwin, true)
+      eq(false, meths.win_is_valid(otherwin))
       -- Close cmdline-window.
-      meths.win_close(0,true)
+      meths.win_close(0, true)
       eq(2, #meths.list_wins())
       eq('', funcs.getcmdwintype())
     end)