Merge olga.mysql.com:/home/igor/mysql-4.1-opt

into  olga.mysql.com:/home/igor/mysql-5.0-opt


mysql-test/r/type_enum.result:
  Auto merged
mysql-test/t/type_enum.test:
  Auto merged
sql/field_conv.cc:
  SCCS merged

mysql-test/r/type_enum.result

@@ -1778,6 +1778,29 @@ drop table t1;
 create table t1(exhausting_charset enum('ABCDEFGHIJKLMNOPQRSTUVWXYZ','
	
 
 !"','#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~','xx\','yy\€','zz亗儎厗噲墛媽崕彁憭摂晼棙櫄洔潪煚、￥ウЖ┆<D096><E29486><EFBFBD>辈炒刀犯购患骄坷谅媚牌侨墒颂臀闲岩釉罩棕仝圮蒉哙徕沅彐玷殛腱眍镳耱篝貊鼬<E8B28A><E9BCAC><EFBFBD><EFBFBD>'));
 ERROR 42000: Field separator argument is not what is expected; check the manual
+CREATE TABLE t1 (
+id INT AUTO_INCREMENT PRIMARY KEY,
+c1 ENUM('a', '', 'b')
+);
+INSERT INTO t1 (c1) VALUES (0), ('a'), (''), ('b');
+Warnings:
+Warning	1265	Data truncated for column 'c1' at row 1
+SELECT id, c1 + 0, c1 FROM t1;
+id	c1 + 0	c1
+1	0	
+2	1	a
+3	2	
+4	3	b
+ALTER TABLE t1 CHANGE c1 c1 ENUM('a', '') NOT NULL;
+Warnings:
+Warning	1265	Data truncated for column 'c1' at row 4
+SELECT id, c1 + 0, c1 FROM t1;
+id	c1 + 0	c1
+1	0	
+2	1	a
+3	2	
+4	0	
+DROP TABLE t1;
 End of 4.1 tests
 create table t1(f1 set('a','b'), index(f1));
 insert into t1 values(''),(''),('a'),('b');

mysql-test/t/type_enum.test

@@ -156,6 +156,23 @@ drop table t1;
 create table t1(exhausting_charset enum('ABCDEFGHIJKLMNOPQRSTUVWXYZ','
	
 
 !"','#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~','xx\','yy\€','zz亗儎厗噲墛媽崕彁憭摂晼棙櫄洔潪煚、￥ウЖ┆<D096><E29486><EFBFBD>辈炒刀犯购患骄坷谅媚牌侨墒颂臀闲岩釉罩棕仝圮蒉哙徕沅彐玷殛腱眍镳耱篝貊鼬<E8B28A><E9BCAC><EFBFBD><EFBFBD>'));
 
+#
+# Bug #29251: MySQL coerces special 0 enum values to normal '' value
+# when ALTERing the column
+#
+
+CREATE TABLE t1 (
+  id INT AUTO_INCREMENT PRIMARY KEY,
+  c1 ENUM('a', '', 'b')
+);
+INSERT INTO t1 (c1) VALUES (0), ('a'), (''), ('b');
+SELECT id, c1 + 0, c1 FROM t1;
+
+ALTER TABLE t1 CHANGE c1 c1 ENUM('a', '') NOT NULL;
+SELECT id, c1 + 0, c1 FROM t1;
+
+DROP TABLE t1;
+
 --echo End of 4.1 tests
 
 #

sql/field_conv.cc

@@ -307,6 +307,15 @@ static void do_field_string(Copy_field *copy)
 }
 
 
+static void do_field_enum(Copy_field *copy)
+{
+  if (copy->from_field->val_int() == 0)
+    ((Field_enum *) copy->to_field)->store_type((ulonglong) 0);
+  else
+    do_field_string(copy);
+}
+
+
 static void do_field_varbinary_pre50(Copy_field *copy)
 {
   char buff[MAX_FIELD_WIDTH];
@@ -662,7 +671,13 @@ void (*Copy_field::get_copy_func(Field *to,Field *from))(Copy_field*)
 	  to->real_type() == FIELD_TYPE_SET)
       {
 	if (!to->eq_def(from))
-	  return do_field_string;
+        {
+          if (from->real_type() == MYSQL_TYPE_ENUM &&
+              to->real_type() == MYSQL_TYPE_ENUM)
+            return do_field_enum;
+          else
+            return do_field_string;
+        }
       }
       else if (to->charset() != from->charset())
 	return do_field_string;