`bzr push` fails with error 530 (login incorrect)

Are you specifying a username in the ftp url? By default Bazaar opens
an anonymous connection.

Yes: bzr push ftp://username@host/...
In _create_connection (transport/ftp.py) credentials and self._password are None. I've solved the problem adding password='' after the call to mutter(str).

You shouldn't need to do that, you can use:

  bzr push ftp://user:@host/ (note the ':' followed by nothing to specify an empty password)

or
  bzr push ftp://user@host/

and in that case bzr *must* promt you for a password

Can you confirm that both the above solutions work when reverting you change ?

Only the first (ftp://user:@host) works for me, but in an older version of bzr (0.15-0ubuntu2) i could use also the second way.
Thanks for the help anyhow.

That's pretty strange, our test suite explicitly test that bzr prompt you if you supply a user but no password, what OS and what version of bzr are you using ?

andrea@hivepad:~$ bzr --version
Bazaar (bzr) 0.90.0
  Python interpreter: /usr/bin/python 2.5.1.final.0
  Python standard library: /usr/lib/python2.5
  bzrlib: /usr/lib/python2.5/site-packages/bzrlib
  Bazaar configuration: /home/andrea/.bazaar
  Bazaar log file: /home/andrea/.bzr.log

Copyright 2005, 2006, 2007 Canonical Ltd.
http://bazaar-vcs.org/

bzr comes with ABSOLUTELY NO WARRANTY. bzr is free software, and
you may use, modify and redistribute it under the terms of the GNU
General Public License version 2 or later.

andrea@hivepad:~$ uname -a
Linux hivepad 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686 GNU/Linux
andrea@hivepad:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 7.10
Release: 7.10
Codename: gutsy
andrea@hivepad:~$

Ok, this has been fixed in bzr.0.91, this is a duplicate of #137044.

Sorry, I should have think about it earlier.

If you want to stay with bzr.0.90 the fix is pretty simple:

--- bzrlib/transport/ftp.py 2007-08-22 01:41:24 +0000
+++ bzrlib/transport/ftp.py 2007-09-05 07:27:49 +0000
@@ -130,7 +130,7 @@
             connection = ftplib.FTP()
             connection.connect(host=self._host, port=self._port)
             if self._user and self._user != 'anonymous' and \
- password is not None: # '' is a valid password
+ password is None: # '' is a valid password
                 get_password = bzrlib.ui.ui_factory.get_password
                 password = get_password(prompt='FTP %(user)s@%(host)s password',