On Mon, Mar 4, 2013 at 3:20 PM, Paul Moore <[email protected]> wrote: > On 4 March 2013 20:00, Daniel Holth <[email protected]> wrote: >> On Mon, Mar 4, 2013 at 2:41 PM, Paul Moore <[email protected]> wrote: >>> In thinking about how virtualenv would describe the packages it wants >>> to preload in PEP 426 metadata form, it occurred to me that there are >>> scenarios with setuptools and distribute where it's not obvious how to >>> state the requirement you want. Specifically, if you want to install >>> setuptools if it is present, but if not fall back to distribute (for >>> example, if you have a local package repository and no access to PyPI, >>> but setuptools may or may not be present). > [...] >> >> We do have Provides-Dist, although the best way to implement it is an >> open question. > > Good point. So distribute would have "Provides-Dist: setuptools" and I > could just require setuptools. Given that none of this is supported > yet, I'm happy that the spec covers this case, but still need to work > around it for the immediate future.
Provides-Dist doesn't actually work for most of the use cases for alternates, though. For example, if a package that wants to require one of the various mysql adapters, it doesn't make any sense for the mysql packages to declare that they provide each other. ;-) _______________________________________________ Distutils-SIG maillist - [email protected] http://mail.python.org/mailman/listinfo/distutils-sig
