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."

1 files changed, 3 insertions, 2 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index 940586fce01..6dcf32cba07 100644
--- a/sql/item_func.h
+++ b/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(); }