pip: Pandas fails to install on latest pre-release candidate

• Pip version: 10.0.0b2
• Python version: PyPy 5.10.0 with GCC 6.2.0
• Operating system: Ubuntu 16.04

Description:

We are creating a new virtualenv using PyPy and then attempting to install the package ‘pandas’. Everything is running inside a clean Docker container. This bug does not occur with the same conditions and Pip 9.0.3. We are using a DevPI server to host our own packages, which mirrors content from PyPI. This does not appear to be an issue with Cython being available, as I can install it directly.

What I’ve run:

root@9b34418ce20d:/# /opt/pypy/bin/pypy /usr/lib/python2.7/dist-packages/virtualenv.py -p /opt/pypy/bin/pypy /opt/pypyenv
Already using interpreter /opt/pypy/bin/pypy
New pypy executable in /opt/pypyenv/bin/pypy
Installing setuptools, pkg_resources, pip, wheel...done.
root@9b34418ce20d:/# /opt/pypyenv/bin/pip freeze --all
cffi==1.11.2
greenlet==0.4.12
pip==10.0.0b2
pkg-resources==0.0.0
readline==6.2.4.1
setuptools==39.0.1
wheel==0.31.0

root@9b34418ce20d:/# /opt/pypyenv/bin/pip install pandas
Looking in indexes: https://devpi.myindex/root/myindex/+simple/
Collecting pandas
  Downloading https://devpi.myindex/root/pypi/+f/c7a/2757b60774825/pandas-0.22.0.tar.gz (11.3MB)
    100% |################################| 11.3MB 1.5MB/s 
  Could not find a version that satisfies the requirement Cython (from versions: )
No matching distribution found for Cython

root@9b34418ce20d:/# /opt/pypyenv/bin/pip install cython
Looking in indexes: https://devpi.myindex/root/myindex/+simple/
Collecting cython
  Downloading https://devpi.myindex/root/pypi/+f/c54/9effadb52d90b/Cython-0.28.1.tar.gz (1.8MB)
    100% |################################| 1.8MB 2.8MB/s 
Building wheels for collected packages: cython
  Running setup.py bdist_wheel for cython ... done
  Stored in directory: /root/.cache/pip/wheels/8e/21/58/4a0b5de660445a5a2c957575e2de6c2465df8c7c8310ae2e42
Successfully built cython
Installing collected packages: cython
  The scripts cygdb, cython and cythonize are installed in '/opt/pypyenv/bin' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed cython-0.28.1