How to solve collective.js.jqueryui versioning for both Plone 4.2 and 4.3 - plone

Question

I have an addon which I want to update to be compatible with Plone4.3, but which should remain functional when Plone4.2 users do an upgrade.
The readme says this:
For Plone 3 you need version 1.7.x of this package
Plone < 4.3 Use version < 1.9
How can I configure this kind of version-specific dependency in setup.py?

Answer 1

Actually it's c.js.jqueryui which should pin the Plone-versions in their tag-releases, IMHO.
So you should contact the authors probably.
To be consequent, you should add 'Products.CMFPlone' as a dependency, too, but I don't know what is best practice here.
Anyway, to answer your question, here is a possibilty to distinct, whether we have a Plone-3 or not:
In your setup.py add at the top
import glob
# BBB: Append Plone-3-specific version-pinnings
# to `install_requires`, in case third-party-eggs
# do not specify their requirement-versions.
# Assumes, Plone-eggs are in the same directory
# as this egg, which is given, if fetched of pypi.
# Otherwise assumes, you know how to tweak
# buildout and pin versions yourself.
# Collect P3-eggs in eggs-directory:
plone3_eggs = glob.glob('../Products.CMFPlone-3*')
# Found something?
if len(plone3_eggs) > 0:
# Expects `install_requires=[ ... ] + plone3_requires,`
# in setup-method below, to take effect:
plone3_requires = [
'collective.js.jqueryui<=1.7',
# Add more P3-pins here.
]
And install_requires in the setup-method, gets this:
install_requires= [
'setuptools',
'collective.js.jqueryui',
] + plone3_requires,