I've been having issues with pip the last few days. I don't know what's causing it.
However, using apt's version of pip (without upgrading) seems to break when installing modules with dependencies.
Can anyone else reproduce this? Try:
Yup, this seems to be because Debian/Raspbian stable's version of pip (1.5.6) doesn't handle dependency installation order correctly. In this case, part of the dependency tree goes like this:
ipython depends on simplegeneric, which depends on packaging, which depends on six.
So, the installation should
do six, then packaging, then simplegeneric, then ipython (amongst all the other packages it's doing). Unfortunately it tries to do simplegeneric first and this breaks. The newer pip handles the dependency order correctly.
Why has this only broken now? I'd guess one of the packages in that list got updated since the last time you tried and either grew some new dependencies or re-ordered the existing ones (if I recall correctly, order of dependencies mattered with the ancient pip - I vaguely recall having to jiggle the order of them in the past to make stuff work on vanilla installs).
Anyway, it's resolvable without having to upgrade the system pip. Install the dependencies it gets wrong yourself first, then try installing ipython. The following ordering is the minimum I could find that still works:
Code: Select all
pip install appdirs
pip install packaging
pip install ipython