At 10:54 AM 3/25/2008 -0400, Alexander Michael wrote:
On Tue, Mar 25, 2008 at 10:14 AM, Chris Withers <chris@simplistix.co.uk> wrote:
Alexander Michael wrote:
I am far from the authority on these topics, but my understanding as a user is that PEPs 241,314,345
So PEP 345 is implemented in Python 2.5?
Yes.
attempt to address these issues but are not used in practice.
How come? Does distutils in 2.5 or setuptools not generate the required PKG-INFO?
IIUC, as far as distutils goes, the metadata shows-up in the sdist, but not in site-packages, so it isn't really useful for introspecting an installation. The ability to specify requirements is virtually undocumented and isn't used in practice to my knowledge. Setuptools makes both pieces of information introspectable for packages it installs (but provides its own way of specifying requirements).
In fact, setuptools' requirements info is 100% separate from the PEP-specified requirements info. Setuptools allows different requirements for tests, for running the setup script, and for optional add-ons to a project. These requirements also use a different version parsing mechanism etc. One reason for this is that Python 2.3 doesn't support this version stuff, and setuptools was written for 2.3 initially. Another is that the PEP-defined requires/provides data does not allow dependencies to be satisfied merely by looking at target filenames -- i.e., without needing to download them. Using a requires/provides model for dependency resolution would have required new PyPI infrastructure to be built out, whereas a filename-based approach could run on anything. PyPI and the requires/provides PEPs also appear to carry an implicit assumption that these requires/provides are leveled on project+version, without any distinction by Python version and target platform. Setuptools OTOH, assumes that specific dependencies are a property of a *binary* distribution, not a source distribution. (i.e., the PEPs put the dependency info in a source package's PKG-INFO... where it's pretty much useless for any purpose). I've previously posted some of these comments about the requires/provides PEPs on Python-Dev, Distutils-SIG, and Catalog-SIG, with no response from anyone.