upgrade fails over ftp

[Jelmer Vernooij]

charis:~/foo% bzr upgrade ftp://rhonwyn/home/jelmer/foo
Authenticated as <email address hidden>
Format <RepositoryFormatKnit1> for ftp://rhonwyn/home/jelmer/foo/.bzr/ is deprecated - please use 'bzr upgrade' to get better performance
starting upgrade of ftp://rhonwyn/home/jelmer/bio/
making backup of tree history
bzr: ERROR: Generic path error: './branch/lock': error with list_dir: 550 No files found.
)

[John A Meinel (jameinel)]

This is a known problem with some FTP servers. Basically, instead of returning the empty list when there are no files in a directory, they instead raise a 550 error. The problem is that they strings are not generally helpful as they vary wildly based on the ftp server, and 550 can mean a lot of things. For example:
550 Permission denied
http://support.ipswitch.com/kb/WS-20000817-DM02.htm
versus
550 No such file
http://support.ipswitch.com/kb/WS-20010403-DM01.htm

According to the second link 550 is supposed to be a permission error. And it is a bit rude of them to treat "no files in directory" as a permission problem.

Do you know the FTP server which is on "rhonwyn"?

A while back we encountered this with a 450 error. We have this code in "bzrlib/transport/ftp/__init__.py"
except ftplib.error_temp, e:
    # xs4all's ftp server raises a 450 temp error when listing an empty
    # directory. Check for that and just return an empty list in that
    # case. See bug #215522
    if str(e).lower().startswith('450 no files found'):
        mutter('FTP Server returned "%s" for nlst.'
               ' Assuming it means empty directory',
               str(e))
        return []
    raise

So either
a) You have a permission issue on that directory or
b) It is given a bogus error rather than just saying there isn't anything ther.

I'm also really surprised that .bzr/branch/lock is failing. As we never have a cause (that *I* know of) to list that directory. We *do* a list on .bzr/repository/obsolete_packs which is where this came up in the past.

[John A Meinel (jameinel)]

We need more info about the specific trigger. A traceback would be nice. Also I would like documented what version of server is causing this. And is 550 a 'temp' error or a 'permanent' error?

[Martin Pool (mbp)]

So it seems to me this is only incidentally to do with upgrade, and the real bug is: some ftp servers give error 550 to listdir if it's an empty directory, and we should handle that.

[Martin Pool (mbp)]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

  tags ftp
  title "ftp server gives error listing empty directory"
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEARECAAYFAklv4SUACgkQPGPKP6Cz6IuikQCffo/2gfp/F8OsVsr7CBZhTREd
yvIAn3EKuJxLjUunF6/hMcNhyLN1tXoc
=acX4
-----END PGP SIGNATURE-----

[Jelmer Vernooij (jelmer)]

I suspect this was running a Heimdal ftp server.