[Numpy-discussion] Proposal: stop supporting 'setup.py install'; start requiring 'pip install .' instead
morph at debian.org
Wed Oct 28 19:28:32 EDT 2015
please, pretty please, do not disable setup.py install or at least
keep providing a way for distribution (Debian in this case) to be able
to build/install numpy in a temporary location for packaging reasons.
pip is not the solution for us
On Tue, Oct 27, 2015 at 12:31 AM, Nathaniel Smith <njs at pobox.com> wrote:
> Hi all,
> Apparently it is not well known that if you have a Python project
> source tree (e.g., a numpy checkout), then the correct way to install
> it is NOT to type
> python setup.py install # bad and broken!
> but rather to type
> pip install .
> (I.e., pip install isn't just for packages on pypi -- you can also
> pass it the path to an arbitrary source directory or the URL of a
> source tarball and it will do its thing. In this case "install ."
> means "install the project in the current directory".)
> These don't quite have identical results -- the main difference is
> that the latter makes sure that proper metadata gets installed so that
> later on it will be possible to upgrade or uninstall correctly. If you
> call setup.py directly, and then later you try to upgrade your
> package, then it's entirely possible to end up with a mixture of old
> and new versions of the package installed in your PYTHONPATH. (One
> common effect is in numpy's case is that we get people sending us
> mysterious bug reports about failing tests in files don't even exist
> (!) -- because nose is finding tests in files from one version of
> numpy and running them against a different version of numpy.)
> But this isn't the only issue -- using pip also avoids a bunch of
> weird corner cases in distutils/setuptools. E.g., if setup.py uses
> plain distutils, then it turns out this will mangle numpy version
> numbers in ways that cause weird horribleness -- see  for a bug
> report of the form "matplotlib doesn't build anymore" which turned out
> to be because of using 'setup.py install' to install numpy. OTOH if
> setup.py uses setuptools then you get different weirdnesses, like you
> can easily end up with multiple versions of the same library installed
> And finally, an advantage of getting used to using 'pip install .' now
> is that you'll be prepared for the glorious future when we kill
> distutils and get rid of setup.py entirely in favor of something less
> terrible .
> So a proposal that came out of the discussion in  is that we modify
> numpy's setup.py now so that if you try running
> python setup.py install
> you get
> Error: Calling 'setup.py install' directly is NOT SUPPORTED!
> Instead, do:
> pip install .
> Alternatively, if you want to proceed at your own risk, you
> can try 'setup.py install --force-raw-setup.py'
> For more information see http://...
> (Other setup.py commands would continue to work as normal.)
> I believe that this would also break both 'easy_install numpy', and
> attempts to install numpy via the setup_requires= argument to
> setuptools.setup (because setup_requires= implicitly calls
> easy_install). install_requires= would *not* be affected, and
> setup_requires= would still be fine in cases where numpy was already
> This would hopefully cut down on the amount of time everyone spends
> trying to track down these stupid weird bugs, but it will also require
> some adjustment in people's workflows, so... objections? concerns?
>  https://github.com/numpy/numpy/issues/6551
>  https://mail.python.org/pipermail/distutils-sig/2015-October/027360.html
> Nathaniel J. Smith -- http://vorpus.org
> NumPy-Discussion mailing list
> NumPy-Discussion at scipy.org
Sandro Tosi (aka morph, morpheus, matrixhasu)
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