Bug#58396 group_concat and explain extended are still crashy

Explain fails at fix_fields stage and some items are left unfixed,
particulary Item_group_concat. Item_group_concat::orig_args field
is uninitialized in this case and Item_group_concat::print call 
leads to crash.
The fix:
move the initialization of Item_group_concat::orig_args
into constructor.


mysql-test/r/func_gconcat.result:
  test case
mysql-test/t/func_gconcat.test:
  test case
sql/item_sum.cc:
  move the initialization of Item_group_concat::orig_args
  into constructor.

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 65f8222d38b..a60a6b3ef95 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -3003,6 +3003,7 @@ Item_func_group_concat(Name_resolution_context *context_arg,
       order_item->item= arg_ptr++;
     }
   }
+  memcpy(orig_args, args, sizeof(Item*) * arg_count);
 }
 
 
@@ -3233,7 +3234,6 @@ Item_func_group_concat::fix_fields(THD *thd, Item **ref)
   if (check_sum_func(thd, ref))
     return TRUE;
 
-  memcpy (orig_args, args, sizeof (Item *) * arg_count);
   fixed= 1;
   return FALSE;
 }