Bug #26537: item_unhex() was not expected

to return NULL for non-NULL arguments.
This is not the case as it can return NULL
for invalid hexidecimal strings.
Fixed by setting the maybe_null flag.

1 files changed, 5 insertions, 1 deletions

diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index 60547d00a5c..778ea6e9496 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -605,7 +605,11 @@ class Item_func_unhex :public Item_str_func
 {
   String tmp_value;
 public:
-  Item_func_unhex(Item *a) :Item_str_func(a) {}
+  Item_func_unhex(Item *a) :Item_str_func(a) 
+  { 
+    /* there can be bad hex strings */
+    maybe_null= 1; 
+  }
   const char *func_name() const { return "unhex"; }
   String *val_str(String *);
   void fix_length_and_dec()