On Mon, May 13, 2013 at 10:03 AM, Daniel Holth <dho...@gmail.com> wrote: > It is very difficult to guarantee that your library will never work > with any newer version of some other library, but if you can (e.g. > python-dateutil, versions >= 2 being exclusively Python 3 compatible), > a < or <= qualifier may be appropriate. != is a good one if you know > an exact version of some other library is incompatible. == just causes > problems because it gets in the way of the integrator who has a lot > more information than the library-author-from-some-time-ago.
The confusion about when to use == comes from the deployment side. It is common to use == in a requirements file when deploying (you tested your application on some exact set of versions), rooting your project's dependency graph with exact distributions. It is almost never useful for interior nodes of a dependency graph (setup.py's install_requires) to declare dependencies on exact versions. a==4 -> b -> c vs. a -> b==7 -> c Usually == crops up when something breaks and the packager decides to pin the known working version of some dependency in setup.py instead of forbidding the known-broken version. _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org http://mail.python.org/mailman/listinfo/distutils-sig
