added checking for old cuted value in Field_enum::store

(bug #2023)

mysql-test/r/type_enum.result

@@ -1636,3 +1636,13 @@ t1	CREATE TABLE `t1` (
   `a` enum('','a','b') NOT NULL default 'b'
 ) TYPE=MyISAM
 drop table t1;
+create table t1 (a enum ('0','1'));
+insert into t1 set a='foobar';
+select * from t1;
+a
+
+update t1 set a = replace(a,'x','y');
+select * from t1;
+a
+
+drop table t1;

mysql-test/t/type_enum.test

@@ -21,3 +21,14 @@ drop table t1;
 create table t1 (a enum (' ','a','b ') not null default 'b ');
 show create table t1;
 drop table t1;
+
+#
+# Tests of wrong enum values (bug #2023)
+#
+
+create table t1 (a enum ('0','1'));
+insert into t1 set a='foobar';
+select * from t1;
+update t1 set a = replace(a,'x','y');
+select * from t1;
+drop table t1;
\ No newline at end of file

sql/field.cc

@@ -4623,7 +4623,7 @@ void Field_enum::store(const char *from,uint length)
   uint tmp=find_enum(typelib,from,length);
   if (!tmp)
   {
-    if (length < 6)			// Can't be more than 99999 enums
+    if (from && length < 6) // Can't be more than 99999 enums
     {
       /* This is for reading numbers with LOAD DATA INFILE */
       char buff[7], *end;