[Python-Dev] Edits to Metadata 1.2 to add extras (optional dependencies)
dholth at gmail.com
Wed Aug 15 16:49:42 CEST 2012
I've drafted some edits to Metadata 1.2 with valuable feedback from
distutils-sig (special thanks to Erik Bray), which seems to have no
more comments on the issue after about 6 weeks. Let me know if you
have an opinion, or if you will have one during some bounded time in
Metadata 1.2 (PEP 345), a non-final PEP that has been adopted by
approximately 10 of the latest sdists from pypy, cannot represent the
setuptools "extras" (optional dependencies) feature. This is a problem
because about 1600+ or 10% of the packages hosted on pypy define
"extras" as measured in May of this year.
The edit implements the extras feature by adding a new condition
"extra == 'name'" to the Metadata 1.2 environment markers.
Requirements with this marker are only installed when the named
optional feature is requested. Valid extras for a package must be
declared with Provides-Extra: name.
It also adds Setup-Requires-Dist as a way to specify requirements
needed during an install as opposed to during runtime.
Setup-Requires-Dist (multiple use)
Like Requires-Dist, but names dependencies needed while the
distributions's distutils / packaging `setup.py` / `setup.cfg` is run.
Provides-Extra (multiple use)
A string containing the name of an optional feature.
Requires-Dist: reportlab; extra == 'pdf'
Requires-Dist: nose; extra == 'test'
Requires-Dist: sphinx; extra == 'doc'
(full changeset on
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