ctype_utf8.result:

  adding test case
sql_table.cc:
  sql_table.cc:
  - do not create a new item when charsets are the same
  - return ER_INVALID_DEFAULT if default value cannot
    be converted into the column character set.
item.cc:
  - Allow conversion not only to Unicode,
    but also to and from "binary".
  - Adding safe_charset_converter() for Item_num
    and Item_varbinary, returning a fixed const Item.

mysql-test/r/ctype_utf8.result

@@ -905,6 +905,10 @@ select * from t1 where city = 'Durban ';
 id	city
 2	Durban
 drop table t1;
+create table t1 (x set('A', 'B') default 0) character set utf8;
+ERROR 42000: Invalid default value for 'x'
+create table t1 (x enum('A', 'B') default 0) character set utf8;
+ERROR 42000: Invalid default value for 'x'
 SET NAMES UTF8;
 CREATE TABLE t1 (
 `id` int(20) NOT NULL auto_increment,

mysql-test/t/ctype_utf8.test

@@ -747,6 +747,15 @@ select * from t1 where city = 'Durban';
 select * from t1 where city = 'Durban ';
 drop table t1;
 
+#
+# Bug #11819 CREATE TABLE with a SET DEFAULT 0 and UTF8 crashes server.
+#
+--error 1067
+create table t1 (x set('A', 'B') default 0) character set utf8;
+--error 1067
+create table t1 (x enum('A', 'B') default 0) character set utf8;
+
+
 #
 # Test for bug #11167: join for utf8 varchar value longer than 255 bytes 
 #

sql/item.cc

@@ -212,15 +212,43 @@ bool Item::eq(const Item *item, bool binary_cmp) const
 Item *Item::safe_charset_converter(CHARSET_INFO *tocs)
 {
   /*
+    Allow conversion from and to "binary".
     Don't allow automatic conversion to non-Unicode charsets,
     as it potentially loses data.
   */
-  if (!(tocs->state & MY_CS_UNICODE))
+  if (collation.collation != &my_charset_bin &&
+      tocs != &my_charset_bin &&
+      !(tocs->state & MY_CS_UNICODE))
     return NULL; // safe conversion is not possible
   return new Item_func_conv_charset(this, tocs);
 }
 
 
+/*
+  Created mostly for mysql_prepare_table(). Important
+  when a string ENUM/SET column is described with a numeric default value:
+
+  CREATE TABLE t1(a SET('a') DEFAULT 1);
+
+  We cannot use generic Item::safe_charset_converter(), because
+  the latter returns a non-fixed Item, so val_str() crashes afterwards.
+  Override Item_num method, to return a fixed item.
+*/
+Item *Item_num::safe_charset_converter(CHARSET_INFO *tocs)
+{
+  Item_string *conv;
+  char buf[64];
+  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
+  s= val_str(&tmp);
+  if ((conv= new Item_string(s->ptr(), s->length(), s->charset())))
+  {
+    conv->str_value.copy();
+    conv->str_value.shrink_to_length();
+  }
+  return conv;
+}
+
+
 Item *Item_string::safe_charset_converter(CHARSET_INFO *tocs)
 {
   Item_string *conv;
@@ -2151,6 +2179,20 @@ bool Item_varbinary::eq(const Item *arg, bool binary_cmp) const
   return FALSE;
 }
 
+
+Item *Item_varbinary::safe_charset_converter(CHARSET_INFO *tocs)
+{
+  Item_string *conv;
+  String tmp, *str= val_str(&tmp);
+
+  if (!(conv= new Item_string(str->ptr(), str->length(), tocs)))
+    return NULL;
+  conv->str_value.copy();
+  conv->str_value.shrink_to_length();
+  return conv;
+}
+
+
 /*
   Pack data in buffer for sending
 */

sql/item.h

@@ -334,6 +334,7 @@ class Item_num: public Item
 {
 public:
   virtual Item_num *neg()= 0;
+  Item *safe_charset_converter(CHARSET_INFO *tocs);
 };
 
 #define NO_CACHED_FIELD_INDEX ((uint)(-1))
@@ -835,6 +836,7 @@ public:
   // to prevent drop fixed flag (no need parent cleanup call)
   void cleanup() {}
   bool eq(const Item *item, bool binary_cmp) const;
+  virtual Item *safe_charset_converter(CHARSET_INFO *tocs);
 };
 
 

sql/sql_table.cc

@@ -557,10 +557,15 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
         Convert the default value from client character
         set into the column character set if necessary.
       */
-      if (sql_field->def)
+      if (sql_field->def && cs != sql_field->def->collation.collation)
+      {
+        if (!(sql_field->def= 
+              sql_field->def->safe_charset_converter(cs)))
         {
-        sql_field->def= 
-          sql_field->def->safe_charset_converter(cs);
+          /* Could not convert */
+          my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
+          DBUG_RETURN(-1);
+        }
       }
 
       if (sql_field->sql_type == FIELD_TYPE_SET)