Fix for bug #32559: connection hangs on query with name_const

Problem: passing a non-constant name to the NAME_CONST function results in a crash.

Fix: check the NAME_CONST name argument; return fake item type if we got
non-constant argument(s).


mysql-test/r/func_misc.result:
  Fix for bug #32559: connection hangs on query with name_const
    - test result.
mysql-test/t/func_misc.test:
  Fix for bug #32559: connection hangs on query with name_const
    - test case.
sql/item.cc:
  Fix for bug #32559: connection hangs on query with name_const
    - Item_name_const::type() now returns NULL_ITEM if non-constant arguments 
      were used to create the item to avoid wrong type casting.
sql/item.h:
  Fix for bug #32559: connection hangs on query with name_const
    - NAME_CONST name argument checked for invariability.

1 files changed, 3 insertions, 1 deletions

diff --git a/sql/item.h b/sql/item.h
index a1135c2c725..fbf4b94b276 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1111,11 +1111,13 @@ class Item_name_const : public Item
 {
   Item *value_item;
   Item *name_item;
+  bool valid_args;
 public:
   Item_name_const(Item *name_arg, Item *val):
     value_item(val), name_item(name_arg)
   {
-    if(!value_item->basic_const_item())
+    if (!(valid_args= name_item->basic_const_item() & 
+                      value_item->basic_const_item()))
       my_error(ER_WRONG_ARGUMENTS, MYF(0), "NAME_CONST");
     Item::maybe_null= TRUE;
   }