Comment 2 for bug 811721

What Zooko said. (I reviewed the changes to pycryptopp and they all look harmless or low-risk.)

Bear in mind that debian/control in Tahoe-LAFS also needs to be changed to depend on "python-pycryptopp (>= 0.5.20)" here: http://bazaar.launchpad.net/~jtaylor/ubuntu/oneiric/tahoe-lafs/fix-769935/view/head:/debian/control#L16 . Otherwise, if we are on an x86[-64] machine and the installed pycryptopp package declares its version as >= 0.5.14 but < 0.5.20, it won't be upgraded (if I understand the behaviour of .deb-based package managers correctly) and so the dependency in Tahoe's _auto_deps.py won't be met.

For future reference, it would be better if any Ubuntu- or Debian-patched version of pycryptopp (or any other Tahoe dependency) would declare its version in a way that allows us to recognize and accept it in the setuptools dependency language. For example, if the patched pycryptopp had declared itself as as 0.5.17.post1, then we could have written the Tahoe dependency as "pycryptopp == 0.5.17.post1, >= 0.5.20", and everything would have gone much more smoothly. The version numbers should follow http://www.python.org/dev/peps/pep-0396/ . This would probably be a good policy for Python packages in general.