vim-patch:8.0.0486

Problem:    Crash and endless loop when closing windows in a SessionLoadPost
            autocommand.
Solution:   Check for valid tabpage.  (partly neovim/neovim#6308)

8c752bd6c4

Closes #6308

src/nvim/fileio.c

@@ -6464,6 +6464,12 @@ win_found:
     win_remove(curwin, NULL);
     aucmd_win_used = false;
     last_status(false);         // may need to remove last status line
+
+    if (!valid_tabpage_win(curtab)) {
+      // no valid window in current tabpage
+      close_tabpage(curtab);
+    }
+
     restore_snapshot(SNAP_AUCMD_IDX, false);
     (void)win_comp_pos();       // recompute window positions
     unblock_autocmds();