On Sun, Jan 6, 2019 at 12:45 PM Thomas Robitaille < thomas.robitai...@gmail.com> wrote:
> Hi all, > > Back in December I started getting failures in continuous integration > as well as reports of failures from users of installation issues for a > couple of packages. The problem can be easily reproduced in a Docker > container with: > > FROM ubuntu:16.04 > RUN apt-get update > RUN apt-get install -y python3 python3-dev python3-pip python3-wheel > RUN pip3 install fast-histogram > RUN python3 -c 'import fast_histogram' > > Doing this results in the following traceback: > > ImportError: No module named 'numpy.core._multiarray_umath' > Traceback (most recent call last): > File "<string>", line 1, in <module> > File > "/usr/local/lib/python3.5/dist-packages/fast_histogram/__init__.py", > line 1, in <module> > from .histogram import * > File > "/usr/local/lib/python3.5/dist-packages/fast_histogram/histogram.py", > line 7, in <module> > from ._histogram_core import (_histogram1d, > ImportError: numpy.core.multiarray failed to import > > I've seen similar issues with other packages too. The key is that the > fast-histogram package defines: > > setup_requires=['numpy'] > > in the setup.py (since the package has a C extension that uses the > Numpy C API) and numpy is needed before the install_requires > dependencies are installed: > > https://github.com/astrofrog/fast-histogram/blob/master/setup.py > > Now this normally works fine, but the issues I saw started when the > first 1.16 RC was made available, when installing into an environment > in which numpy is not already installed. > > My understanding is that setup_requires is honored by easy_install > (even if installing the main package with pip), which doesn't ignore > pre-releases. Thus, the package is built against the 1.16 RC but then > 1.15 is installed due to: > > install_requires=['numpy'] > > which is honored by pip. > Oh fun. Thanks for explaining this! > I think that the correct solution is to make sure that: > > [build-system] > requires = ["setuptools", "wheel", "numpy"] > > is added to the pyproject.toml file (as per PEP 518). To clarify: you're talking about fast-histogram's pyproject.toml file right? This then works > properly with recent versions of pip (>10 I think). I think removing > setup_requires then makes sense because it'd be better to have an > error with older versions of pip that numpy is not installed rather > than having the package built against the wrong version. > This is a pretty hacky solution, needed because pip doesn't support setup_requires, but yes it should work and I can't think of a better way. Cheers, Ralf > I know this is a temporary issue in the sense that it will go away > once the final version of 1.16 is out, but I just wanted to share this > as a heads-up in case you get reports of issues from other people, and > also to check whether there are any other solutions/workarounds to be > aware of? (to avoid a similar situation in future). > > Thanks, > Tom > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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