Bug#13871079 RQG_MYISAM_DML_ALTER_VALGRIND FAILS ON VALGRIND PN PB2

The class Copy_field contains a String tmp, 
which may allocate memory on the heap.
That means that all instances of Copy_field
must be properly destroyed. Alas they are not.

Solution: don't use Copy_field::tmp for copying
from_field => tmp => to_field
in do_field_string()

1 files changed, 7 insertions, 1 deletions

diff --git a/sql/field.h b/sql/field.h
index b4adb764b22..674b58108d4 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -1985,7 +1985,8 @@ public:
     :Field_enum(ptr_arg, len_arg, null_ptr_arg, null_bit_arg,
 		    unireg_check_arg, field_name_arg,
                 packlength_arg,
-                typelib_arg,charset_arg)
+                typelib_arg,charset_arg),
+      empty_set_string("", 0, charset_arg)
     {
       flags=(flags & ~ENUM_FLAG) | SET_FLAG;
     }
@@ -1996,8 +1997,11 @@ public:
   virtual bool zero_pack() const { return 1; }
   String *val_str(String*,String *);
   void sql_type(String &str) const;
+  uint size_of() const { return sizeof(*this); }
   enum_field_types real_type() const { return MYSQL_TYPE_SET; }
   bool has_charset(void) const { return TRUE; }
+private:
+  const String empty_set_string;
 };
 
 
@@ -2192,6 +2196,8 @@ public:
   {
     return (flags & (BINCMP_FLAG | BINARY_FLAG)) != 0;
   }
+private:
+  const String empty_set_string;
 };