Fix for bug #6840: Default value is not checked in ALTER column SET DEFAULT 'x'

mysql-test/r/type_enum.result

@@ -1737,3 +1737,11 @@ def	test	t1	t1	c	c	254	3	0	Y	384	0	8
 a	b	c
 Y	NULL	NULL
 drop table t1;
+create table t1 (a enum('x','y') default 'x');
+alter table t1 alter a set default 'z';
+ERROR 42000: Invalid default value for 'a'
+drop table t1;
+create table t1 (a set('x','y') default 'x');
+alter table t1 alter a set default 'z';
+ERROR 42000: Invalid default value for 'a'
+drop table t1;

mysql-test/t/type_enum.test

@@ -111,5 +111,18 @@ alter table t1 add b set ('Y','N') CHARACTER SET utf8 COLLATE utf8_bin;
 alter table t1 add c enum ('Y','N') CHARACTER SET utf8 COLLATE utf8_bin;
 --enable_metadata
 select * from t1;
---disable metadata
+--disable_metadata
+drop table t1;
+
+#
+# Bug #6840  Default value is not checked in ALTER column SET DEFAULT 'x'
+#
+create table t1 (a enum('x','y') default 'x');
+--error 1067
+alter table t1 alter a set default 'z';
+drop table t1;
+
+create table t1 (a set('x','y') default 'x');
+--error 1067
+alter table t1 alter a set default 'z';
 drop table t1;

sql/sql_table.cc

@@ -485,25 +485,27 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       DBUG_RETURN(-1);
     }
 
-    if ((sql_field->sql_type == FIELD_TYPE_SET ||
-         sql_field->sql_type == FIELD_TYPE_ENUM) && !sql_field->interval)
+    if (sql_field->sql_type == FIELD_TYPE_SET ||
+        sql_field->sql_type == FIELD_TYPE_ENUM)
     {
       uint32 dummy;
       CHARSET_INFO *cs= sql_field->charset;
-      TYPELIB *interval;
+      TYPELIB *interval= sql_field->interval;
 
       /*
         Create typelib from interval_list, and if necessary
         convert strings from client character set to the
         column character set.
       */
-
+      if (!interval)
+      {
         interval= sql_field->interval= typelib(sql_field->interval_list);
         List_iterator<String> it(sql_field->interval_list);
         String conv, *tmp;
         for (uint i= 0; (tmp= it++); i++)
         {
-        if (String::needs_conversion(tmp->length(), tmp->charset(), cs, &dummy))
+          if (String::needs_conversion(tmp->length(), tmp->charset(),
+                                       cs, &dummy))
           {
             uint cnv_errs;
             conv.copy(tmp->ptr(), tmp->length(), tmp->charset(), cs, &cnv_errs);
@@ -521,7 +523,7 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
           ((uchar *)interval->type_names[i])[lengthsp]= '\0';
         }
         sql_field->interval_list.empty(); // Don't need interval_list anymore
-
+      }
 
       /*
         Convert the default value from client character