On Fri, Sep 18, 2015, at 08:49 AM, Julien Puydt wrote: > What is annoying is that some of the packages have a dependency chain > going in some way, and an extra dependency chain going the other way. > For a concrete example, ipykernel depends on ipython... but ipython has > an extra-dep on ipykernel.
The extra deps in IPython are for backwards compatibility, so that if people have scripted (or remembered) commands like "pip install ipython[notebook]", they will continue to work, by pulling in the separated package which now contains that functionality. In time we will probably remove these. I'd recommend that you ignore these compatibility dependencies (that is, all the extra dependency groups of IPython besides doc and test). Thomas
