Bug with alter tables ?

Hi,

I think i've found a bug in MySQL. I use MySQL 4.1.4. I've not tested
with 4.1.5 but there is absolutely nothing in the change log about it.

I got strange results in a connection when the table is altered
in another connection.

The problem can be reproduced with the lines below : 
# Create a test table
create table test (id integer primary key, col1 varchar(10));
insert into test values(1, 'a'), (2, 'b'), (3,'a');
start transaction;
# Checking the rows : ok, got 3 rows
select * from test;    
# In ANOTHER CONNECTION, alter the table  (alter table test add index (col1);)
# Checking the rows again (again in the first connection): got 0 rows ! This seems a bug to me
# Why should this connection see the table as empty ?
select * from test;    

Is it a really bug or does i missed something ?

Thank you for your answer.

Bertrand Lanneau.