Bug with casa-pre and ipython when pip installing

[keflavich]

This is a weird interaction between several packages, but I want to report it.

If you attempt to install astroquery (and perhaps any of several other packages, but that's not clear) using

import pip
pip.main(['install', 'astroquery', '--user'])

CASA may fail to start (at least, CASA 5.3.0-121) with a failure like:

Traceback (most recent call last):
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/start_casa.py", line 10, in <module>
    from IPython import start_ipython
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/site-packages/IPython/__init__.py", line 48, in <module>
    from .core.application import Application
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/site-packages/IPython/core/application.py", line 25, in <module>
    from IPython.core import release, crashhandler
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/site-packages/IPython/core/crashhandler.py", line 28, in <module>
    from IPython.core import ultratb
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/site-packages/IPython/core/ultratb.py", line 128, in <module>
    from IPython.utils.terminal import get_terminal_size
  File "/home/casa/packages/RHEL6/prerelease/casa-prerelease-5.3.0-121/lib/python2.7/site-packages/IPython/utils/terminal.py", line 22, in <module>
    from backports.shutil_get_terminal_size import get_terminal_size as _get_terminal_size
ImportError: No module named shutil_get_terminal_size

The solution is to use pip to install the shutil_get_terminal_size package:

pip install backports.shutil_get_terminal_size --user

There are several ipython Issue threads that will turn up with this information if you google the ImportError.

[keflavich]

Report from Leonardo: the solution above doesn't work unless you try harder:

pip uninstall backports.shutil_get_terminal_size

followed by:

pip install backports.shutil_get_terminal_size —user