Bug#34749: Server crash when using NAME_CONST() with an aggregate function

NAME_CONST('whatever', -1) * MAX(whatever) bombed since -1 was
not seen as constant, but as FUNCTION_UNARY_MINUS(constant)
while we are at the same time pretending it was a basic const
item. This confused the aggregate handlers in exciting ways.
We now make NAME_CONST() behave more consistently.


mysql-test/r/func_misc.result:
  show that a combination of NAME_CONST('x', -y) and an aggregate
  no longer crashes the server.
mysql-test/t/func_misc.test:
  show that a combination of NAME_CONST('x', -y) and an aggregate
  no longer crashes the server.
sql/ha_ndbcluster_cond.cc:
  tell cluster about "new" function type NEG_FUNC.
  (this was previous identified as UNKNOWN_FUNC,
  so we just handle it the same way, that's all.)
sql/ha_ndbcluster_cond.h:
  tell cluster about "new" function type NEG_FUNC.
  (this was previous identified as UNKNOWN_FUNC,
  so we just handle it the same way, that's all.)
sql/item.cc:
  make NAME_CONST() transparent in that type() of
  -constant is that of constant, not that of unary
  minus (id est, FUNC_ITEM).
sql/item.h:
  Move constructor to item.cc
sql/item_func.h:
  Revert Bug#30832; we can apply the magic more narrowly
  (just for NAME_CONST() rather than all Item_func_neg).
  
  Introduce new function type "NEG_FUNC."

mysql-test/r/func_misc.result

@@ -207,6 +207,25 @@ test
 SELECT NAME_CONST('test', 'test');
 test
 test
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+SELECT NAME_CONST('flag',1)    * MAX(a) FROM t1;
+NAME_CONST('flag',1)    * MAX(a)
+3
+SELECT NAME_CONST('flag',1.5)  * MAX(a) FROM t1;
+NAME_CONST('flag',1.5)  * MAX(a)
+4.5
+SELECT NAME_CONST('flag',-1)   * MAX(a) FROM t1;
+NAME_CONST('flag',-1)   * MAX(a)
+-3
+SELECT NAME_CONST('flag',-1.5) * MAX(a) FROM t1;
+NAME_CONST('flag',-1.5) * MAX(a)
+-4.5
+SELECT NAME_CONST('flag', SQRT(4)) * MAX(a) FROM t1;
+ERROR HY000: Incorrect arguments to NAME_CONST
+SELECT NAME_CONST('flag',-SQRT(4)) * MAX(a) FROM t1;
+ERROR HY000: Incorrect arguments to NAME_CONST
+DROP TABLE t1;
 CREATE TABLE t1 (a int);
 INSERT INTO t1 VALUES (5), (2);
 SELECT NAME_CONST(x,2) FROM (SELECT a x FROM t1) t;

mysql-test/t/func_misc.test

@@ -204,6 +204,24 @@ SELECT NAME_CONST('test', 1.0);
 SELECT NAME_CONST('test', -1.0);
 SELECT NAME_CONST('test', 'test');
 
+#
+# Bug #34749: Server crash when using NAME_CONST() with an aggregate function
+#
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2),(3);
+# NAME_CONST() + aggregate.
+SELECT NAME_CONST('flag',1)    * MAX(a) FROM t1;
+SELECT NAME_CONST('flag',1.5)  * MAX(a) FROM t1;
+# Now, wrap the INT_ITEM in Item_func_neg and watch the pretty explosions
+SELECT NAME_CONST('flag',-1)   * MAX(a) FROM t1;
+SELECT NAME_CONST('flag',-1.5) * MAX(a) FROM t1;
+--error ER_WRONG_ARGUMENTS
+SELECT NAME_CONST('flag', SQRT(4)) * MAX(a) FROM t1;
+--error ER_WRONG_ARGUMENTS
+SELECT NAME_CONST('flag',-SQRT(4)) * MAX(a) FROM t1;
+DROP TABLE t1;
+
 #
 # Bug #27545: erroneous usage of NAME_CONST with a name as the first parameter 
 #             resolved against a column name of a derived table hangs the client

sql/ha_ndbcluster_cond.cc

@@ -117,7 +117,8 @@ void ndb_serialize_cond(const Item *item, void *arg)
           if (item->type() == Item::FUNC_ITEM)
           {
             Item_func *func_item= (Item_func *) item;
-            if (func_item->functype() == Item_func::UNKNOWN_FUNC &&
+            if ((func_item->functype() == Item_func::UNKNOWN_FUNC ||
+                 func_item->functype() == Item_func::NEG_FUNC) &&
                 func_item->const_item())
             {
               // Skip any arguments since we will evaluate function instead
@@ -369,8 +370,9 @@ void ndb_serialize_cond(const Item *item, void *arg)
         {
           Item_func *func_item= (Item_func *) item;
           // Check that we expect a function or functional expression here
-          if (context->expecting(Item::FUNC_ITEM) || 
-              func_item->functype() == Item_func::UNKNOWN_FUNC)
+          if (context->expecting(Item::FUNC_ITEM) ||
+              func_item->functype() == Item_func::UNKNOWN_FUNC ||
+              func_item->functype() == Item_func::NEG_FUNC)
             context->expect_nothing();
           else
           {
@@ -584,6 +586,7 @@ void ndb_serialize_cond(const Item *item, void *arg)
             context->expect(Item::FUNC_ITEM);
             break;
           }
+          case Item_func::NEG_FUNC:
           case Item_func::UNKNOWN_FUNC:
           {
             DBUG_PRINT("info", ("UNKNOWN_FUNC %s", 

sql/ha_ndbcluster_cond.h

@@ -228,6 +228,7 @@ public:
     case (Item_func::ISNOTNULL_FUNC): { return NDB_ISNOTNULL_FUNC; }
     case (Item_func::LIKE_FUNC): { return NDB_LIKE_FUNC; }
     case (Item_func::NOT_FUNC): { return NDB_NOT_FUNC; }
+    case (Item_func::NEG_FUNC): { return NDB_UNKNOWN_FUNC; }
     case (Item_func::UNKNOWN_FUNC): { return NDB_UNKNOWN_FUNC; }
     case (Item_func::COND_AND_FUNC): { return NDB_COND_AND_FUNC; }
     case (Item_func::COND_OR_FUNC): { return NDB_COND_OR_FUNC; }

sql/item.cc

@@ -1207,6 +1207,22 @@ bool Item_name_const::is_null()
   return value_item->is_null();
 }
 
+
+Item_name_const::Item_name_const(Item *name_arg, Item *val):
+    value_item(val), name_item(name_arg)
+{
+  if (!(valid_args= name_item->basic_const_item() &&
+                    (value_item->basic_const_item() ||
+                     ((value_item->type() == FUNC_ITEM) &&
+                      (((Item_func *) value_item)->functype() ==
+                                                 Item_func::NEG_FUNC) &&
+                      (((Item_func *) value_item)->key_item()->type() !=
+                       FUNC_ITEM)))))
+    my_error(ER_WRONG_ARGUMENTS, MYF(0), "NAME_CONST");
+  Item::maybe_null= TRUE;
+}
+
+
 Item::Type Item_name_const::type() const
 {
   /*
@@ -1218,8 +1234,17 @@ Item::Type Item_name_const::type() const
     if (item->type() == FIELD_ITEM) 
       ((Item_field *) item)->... 
     we return NULL_ITEM in the case to avoid wrong casting.
+
+    valid_args guarantees value_item->basic_const_item(); if type is
+    FUNC_ITEM, then we have a fudged item_func_neg() on our hands
+    and return the underlying type.
   */
-  return valid_args ? value_item->type() : NULL_ITEM;
+  return valid_args ?
+             (((value_item->type() == FUNC_ITEM) &&
+               (((Item_func *) value_item)->functype() == Item_func::NEG_FUNC)) ?
+             ((Item_func *) value_item)->key_item()->type() :
+             value_item->type()) :
+           NULL_ITEM;
 }
 
 

sql/item.h

@@ -1113,14 +1113,7 @@ class Item_name_const : public Item
   Item *name_item;
   bool valid_args;
 public:
-  Item_name_const(Item *name_arg, Item *val):
-    value_item(val), name_item(name_arg)
-  {
-    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;
-  }
+  Item_name_const(Item *name_arg, Item *val);
 
   bool fix_fields(THD *, Item **);
 

sql/item_func.h

@@ -54,7 +54,8 @@ public:
                   NOT_FUNC, NOT_ALL_FUNC,
                   NOW_FUNC, TRIG_COND_FUNC,
                   SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
-                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC };
+                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP, UDF_FUNC,
+                  NEG_FUNC };
   enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
                        OPTIMIZE_EQUAL };
   enum Type type() const { return FUNC_ITEM; }
@@ -466,7 +467,7 @@ public:
   longlong int_op();
   my_decimal *decimal_op(my_decimal *);
   const char *func_name() const { return "-"; }
-  virtual bool basic_const_item() const { return args[0]->basic_const_item(); }
+  enum Functype functype() const   { return NEG_FUNC; }
   void fix_length_and_dec();
   void fix_num_length_and_dec();
   uint decimal_precision() const { return args[0]->decimal_precision(); }