"tahoe start" exits with error

[Hannes]

After upgrading to Kubuntu 15.04, I cannot run "tahoe start" any more.

Here's what the command line messages say:

---snip---
STARTING '/home/name/.tahoe'
Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 642, in run
    runApp(config)
  File "/usr/lib/python2.7/dist-packages/twisted/scripts/twistd.py", line 23, in runApp
    _SomeApplicationRunner(config).run()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 376, in run
    self.application = self.createOrGetApplication()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 441, in createOrGetApplication
    application = getApplication(self.config, passphrase)
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 452, in getApplication
    application = service.loadApplication(filename, style, passphrase)
  File "/usr/lib/python2.7/dist-packages/twisted/application/service.py", line 405, in loadApplication
    application = sob.loadValueFromFile(filename, 'application', passphrase)
  File "/usr/lib/python2.7/dist-packages/twisted/persisted/sob.py", line 210, in loadValueFromFile
    exec fileObj in d, d
  File "tahoe-client.tac", line 5, in <module>
    pkg_resources.require('allmydata-tahoe')
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 946, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 838, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (pycrypto 2.6.1 (/usr/lib/python2.7/dist-packages), Requirement.parse('pycrypto==2.1.0,==2.3,>=2.4.1'), set(['allmydata-tahoe']))

Failed to load application: (pycrypto 2.6.1 (/usr/lib/python2.7/dist-packages), Requirement.parse('pycrypto==2.1.0,==2.3,>=2.4.1'), set(['allmydata-tahoe']))
--- snap ---

[Zooko Wilcox-O'Hearn (zooko-j)]

That's because of this change to setuptools which changed the meaning of "," in dependency specifications:

https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2354

You could apply the patch from here:

https://tahoe-lafs.org/trac/tahoe-lafs/changeset/ef455df990c5585e8755d1d791f4dac0ef954956/trunk
https://tahoe-lafs.org/trac/tahoe-lafs/changeset/e73d76eb1b8751b1669e380c82c7ce5065faddad/trunk

But in your case since you already have an adequate version of pycrypto installed, you could also just comment-out the mention of "pycrypto" from `allmydata/_auto_deps.py`.

[Hannes (derhannes)]

Thanks! I will try your proposal.

[Hannes (derhannes)]

I am sorry.
Since I tried installing tahoe-lafs from the sources in the meantime, I can no longer reproduce the original problem and thus cannot properly test the proposed fix.

(Using the sources and after adding some packages via "pip", I can run "tahoe start" just fine.)

[Zooko Wilcox-O'Hearn (zooko-j)]

Dear derhannes: Thanks! I'm glad it is working for you. By the way, I'm happy to hear of another Tahoe-LAFS user! Would you please send me an email at <email address hidden> so I can ask you questions about how you use it and how it works for you?

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Zooko Wilcox-O'Hearn (zooko-j)]

Just a reminder: this has been fixed in upstream Tahoe-LAFS. Here is the ticket in the Tahoe-LAFS issue tracker: https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2354

Here are the patches that fix this issue:

* https://github.com/tahoe-lafs/tahoe-lafs/commit/ef455df990c5585e8755d1d791f4dac0ef954956
* https://github.com/tahoe-lafs/tahoe-lafs/commit/e73d76eb1b8751b1669e380c82c7ce5065faddad

[Daira Hopwood (daira)]

The fix is in Tahoe-LAFS release 1.10.1 (but 1.10.2 is preferred, and is already in Debian testing).