Do not die on ASSERT when sorting an empty input with custom presorter.

We have test that not only the join bucket is available, but that the join
has actually happened, because custom presorters do not implement automatic
joining.

diff --git a/lib/sorter/govern.c b/lib/sorter/govern.c
index 43b1668846fb975c1fb06fdfe415bb38df328586..2d7f4e952626618d3defdf4d67d7133725f2824d 100644 (file)
--- a/lib/sorter/govern.c
+++ b/lib/sorter/govern.c
@@ -77,7 +77,7 @@ sbuck_join_to(struct sort_bucket *b, sh_off_t *sizep)
 static sh_off_t
 sbuck_ins_or_join(struct sort_bucket *b, cnode *list_pos, struct sort_bucket *join, sh_off_t join_size)
 {
-  if (join)
+  if (join && join->runs >= 2)
     {
       if (b)
        sbuck_drop(b);