TypeError: prefetch() takes exactly 2 arguments (1 given)

[Chad Miller]

$ bzr push
Using saved push location: sftp://hostshortnameinsshconfig/home/public/
bzr: ERROR: exceptions.TypeError: prefetch() takes exactly 2 arguments (1 given)

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 930, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1121, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 697, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/builtins.py", line 1393, in run
    use_existing_dir=use_existing_dir, no_tree=no_tree)
  File "/usr/lib/python2.7/dist-packages/bzrlib/push.py", line 84, in _show_push_branch
    dir_to = controldir.ControlDir.open_from_transport(to_transport)
  File "/usr/lib/python2.7/dist-packages/bzrlib/controldir.py", line 718, in open_from_transport
    find_format, transport, redirected)
  File "/usr/lib/python2.7/dist-packages/bzrlib/transport/__init__.py", line 1719, in do_catching_redirections
    return action(transport)
  File "/usr/lib/python2.7/dist-packages/bzrlib/controldir.py", line 706, in find_format
    probers=probers)
  File "/usr/lib/python2.7/dist-packages/bzrlib/controldir.py", line 1151, in find_format
    return prober.probe_transport(transport)
  File "/usr/lib/python2.7/dist-packages/bzrlib/bzrdir.py", line 1237, in probe_transport
    format_string = transport.get_bytes(".bzr/branch-format")
  File "/usr/lib/python2.7/dist-packages/bzrlib/transport/sftp.py", line 422, in get_bytes
    f = self.get(relpath)
  File "/usr/lib/python2.7/dist-packages/bzrlib/transport/sftp.py", line 414, in get
    f.prefetch()
TypeError: prefetch() takes exactly 2 arguments (1 given)

python-paramiko 1.16.0-1
bzr 2.7.0-2ubuntu1
python-bzrlib 2.7.0-2ubuntu1

[Chad Miller (cmiller)]

In paramiko sftp_file.py,

SFTPFile.prefetch takes a file_size parameter after self.

[Vincent Ladeuil (vila)]

@Chad: which ubuntu release ?

> SFTPFile.prefetch takes a file_size parameter after self.

I'm aware of the issue but not up to date, last time I looked the parameter value couldn't be guessed by the caller and internally the default was from a private attribute :-/

[Chad Miller (cmiller)]

There's some crazy paramiko version testing that determines whether prefetch is called at all. Maybe another test is in order.

Which release of what? You mean perhaps "yakkety"? Bzr/Paramiko version numbers are at the bottom of the description.

[Vincent Ladeuil (vila)]

> There's some crazy paramiko version testing that determines whether prefetch is called at all.

Yup, dating from when prefetch was introduced in paramiko, clearly more confusing than relevant theses days.

> Maybe another test is in order.

I was hoping for paramiko to not break backwards compatibility:

https://github.com/paramiko/paramiko/issues/676

Too bad I only discover the above issue (with a proper fix) today (I think this came up from debian but can't find the relevant discussion anymore) :-/

If I'm reading this correctly, paramiko 1.16.2 will fix the compatibility issue.

>> @Chad: which ubuntu release ?
> Which release of what? You mean perhaps "yakkety"?
Yeah, I meant ubuntu but checked with rmadison afterwards:
 python-paramiko | 1.16.0-1 | xenial | all
 python-paramiko | 1.16.0-1 | yakkety | all

Which would mean paramiko was able to enter xenial despite dep8 tests that should have caught that regression :-/

Anyway, in the mean time, as a workaround, you may be able to bzr+ssh instead of sftp (which is inherently slower) ?

[Vincent Ladeuil (vila)]

... otherwise, if we can't get paramiko 1.16.2 in, yes, a test for that specific version will be the way to go.

[Vincent Ladeuil (vila)]

Also, can someone confirm that using bzr+ssh instead of sftp avoids the issue ?

[Jeff Lane  (bladernr)]

@vila Yeah, bzr+ssh seems to work just fine. It's just sftp and paramiko that's broke for me.

[Jelmer Vernooij (jelmer)]

FWIW this is the patch we use in Debian (which only works with newer versions of paramiko):

https://alioth.debian.org/scm/loggerhead/bzr/pkg-bazaar/bzr/2.7/view/head:/debian/patches/16_paramiko_compat