vim-patch:8.2.3862: crash on exit with EXITFREE and using win_execute()

Problem:    Crash on exit with EXITFREE and using win_execute().
Solution:   Also save and restore tp_topframe. (issue vim/vim#9374)

https://github.com/vim/vim/commit/dab17a0689a2f31f69f428975f84b0c3c7ba3030

Couldn't repro the crash in the test, but I only care about this patch so
switch_win sets topframe properly for win_split_ins in nvim_open_win and
nvim_win_set_config.
Add a test using nvim_win_call and :wincmd, as I couldn't repro the issue via
nvim_open_win or nvim_win_set_config (though it's clear they're affected by this
patch).

That said, at that point, could just use {un}use_tabpage inside switch_win
instead, which also updates tp_curwin (though maybe continue to not set it in
restore_win). That would also fix possible inconsistent behaviour such as:

:call win_execute(w, "let curwin_nr1 = tabpagewinnr(1)")
:let curwin_nr2 = tabpagewinnr(1)

Where it's possible for curwin_nr1 != curwin_nr2 if these commands are run from
the 1st tabpage, but window "w" is in the 2nd (as the 1st tabpage's tp_curwin
may still be invalid). I'll probably PR a fix for that later in Vim.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/nvim/eval/window.c b/src/nvim/eval/window.c
index c2b9574579..e54f46dcc3 100644
--- a/src/nvim/eval/window.c
+++ b/src/nvim/eval/window.c
@@ -958,9 +958,11 @@ int switch_win_noblock(switchwin_T *switchwin, win_T *win, tabpage_T *tp, bool n
     if (no_display) {
       curtab->tp_firstwin = firstwin;
       curtab->tp_lastwin = lastwin;
+      curtab->tp_topframe = topframe;
       curtab = tp;
       firstwin = curtab->tp_firstwin;
       lastwin = curtab->tp_lastwin;
+      topframe = curtab->tp_topframe;
     } else {
       goto_tabpage_tp(tp, false, false);
     }
@@ -989,9 +991,11 @@ void restore_win_noblock(switchwin_T *switchwin, bool no_display)
     if (no_display) {
       curtab->tp_firstwin = firstwin;
       curtab->tp_lastwin = lastwin;
+      curtab->tp_topframe = topframe;
       curtab = switchwin->sw_curtab;
       firstwin = curtab->tp_firstwin;
       lastwin = curtab->tp_lastwin;
+      topframe = curtab->tp_topframe;
     } else {
       goto_tabpage_tp(switchwin->sw_curtab, false, false);
     }