fix(api): patch some cmdwin/textlock holes

Problem: there are new ways to escape textlock or break the cmdwin in
nvim_win_set_config and nvim_tabpage_set_win.

Solution: fix them. Use win_goto to check it in nvim_tabpage_set_win and use the
try_start/end pattern like with similar functions such as nvim_set_current_win
(which uses the existing msg_list, if set).

Careful not to use `wp->handle` when printing the window ID in the error message
for nvim_tabpage_set_win, as win_goto autocommands may have freed the window.

On a related note, I have a feeling some API functions ought to be checking
curbuf_locked...

1 files changed, 5 insertions, 1 deletions

diff --git a/src/nvim/api/tabpage.c b/src/nvim/api/tabpage.c
index 040abb1e3f..56a3f1cf23 100644
--- a/src/nvim/api/tabpage.c
+++ b/src/nvim/api/tabpage.c
@@ -146,7 +146,11 @@ void nvim_tabpage_set_win(Tabpage tabpage, Window win, Error *err)
   }
 
   if (tp == curtab) {
-    win_enter(wp, true);
+    try_start();
+    win_goto(wp);
+    if (!try_end(err) && curwin != wp) {
+      api_set_error(err, kErrorTypeException, "Failed to switch to window %d", win);
+    }
   } else if (tp->tp_curwin != wp) {
     tp->tp_prevwin = tp->tp_curwin;
     tp->tp_curwin = wp;