updated for version 7.3.390
Problem: Using NULL buffer pointer in a window.
Solution: Check for w_buffer being NULL in more places. (Bjorn Winckler)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index e81b4a2..519655b 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -3390,6 +3390,13 @@
(flags & ECMD_HIDE) ? 0 : DOBUF_UNLOAD);
#ifdef FEAT_AUTOCMD
+ /* Autocommands may open a new window and leave oldwin open
+ * which leads to crashes since the above call sets
+ * oldwin->w_buffer to NULL. */
+ if (curwin != oldwin && oldwin != aucmd_win
+ && win_valid(oldwin) && oldwin->w_buffer == NULL)
+ win_close(oldwin, FALSE);
+
# ifdef FEAT_EVAL
if (aborting()) /* autocmds may abort script processing */
{