patch 9.1.0048: Abort opening cmdwin if autocmds screw things upv9.1.0048

Problem:  Autocmds triggered from opening the cmdwin (in win_split and
          do_ecmd) can cause issues such as E199, as the current checks
          are insufficient.

Solution: Commands executed from the cmdwin apply to the old curwin/buf,
          so they should be kept in a "suspended" state; abort if
          they've changed. Also abort if cmdwin/buf was tampered with,
          and check that curwin is correct. Try to clean up the cmdwin
          buffer (only if hidden and non-current to simplify things; the
          same approach is used when closing cmdwin normally), and add a
          beep. (Sean Dewar)

It'd be nice to also check that curwin was *really* created by win_split, as
autocommands can change curwin before it returns (so it can't be assumed to be
that of the split); for now, this means that the cmdwin may not be the botwin in
that case, which is probably OK.

closes: #12819

Signed-off-by: Sean Dewar <seandewar@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/proto/window.pro b/src/proto/window.pro
index cfb771d08e..def28bbe41 100644
--- a/src/proto/window.pro
+++ b/src/proto/window.pro
@@ -18,6 +18,7 @@ void leaving_window(win_T *win);
 void entering_window(win_T *win);
 void curwin_init(void);
 void close_windows(buf_T *buf, int keep_curwin);
+int last_window(void);
 int one_window(void);
 int win_close(win_T *win, int free_buf);
 void snapshot_windows_scroll_size(void);