patch 9.0.0961: using deletebufline() may jump to another window

Problem:    Using deletebufline() may jump to another window.
Solution:   Do not use a window where the buffer was only in the past.
            (closes #11594)

src/evalbuffer.c

@@ -109,9 +109,12 @@ find_win_for_curbuf(void)
 {
     wininfo_T *wip;
 
+    // The b_wininfo list should have the windows that recently contained the
+    // buffer, going over this is faster than going over all the windows.
+    // Do check the buffer is still there.
     FOR_ALL_BUF_WININFO(curbuf, wip)
     {
-	if (wip->wi_win != NULL)
+	if (wip->wi_win != NULL && wip->wi_win->w_buffer == curbuf)
 	{
 	    curwin = wip->wi_win;
 	    break;

src/testdir/test_bufline.vim

@@ -288,6 +288,20 @@ func Test_deletebufline_select_mode()
   bwipe!
 endfunc
 
+func Test_deletebufline_popup_window()
+  let popupID = popup_create('foo', {})
+  let bufnr = winbufnr(popupID)
+
+  " Check that deletebufline() brings us back to the same window.
+  new
+  let winid_before = win_getid()
+  call deletebufline(bufnr, 1, '$')
+  call assert_equal(winid_before, win_getid())
+  bwipe
+
+  call popup_close(popupID)
+endfunc
+
 func Test_setbufline_startup_nofile()
   let before =<< trim [CODE]
     set shortmess+=F

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    961,
 /**/
     960,
 /**/