segfault on 0s exposures

[stscirij]

Calcos segfaults on 0s exposures in operations. segfault probability seems to be lower on regular science machines. Seems to be a problem in astropy.io.fits

[jhunkeler]

Dug this out my notes from when we worked on this last time:

Fatal Python error: Segmentation fault

Current thread 0x00007efd7b900700 (most recent call first):
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/astropy-1.2.1-py3.5-linux-x86_64.egg/astropy/io/fits/fitsrec.py", line 646 in __del__
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/calcos-3.1.8-py3.5-linux-x86_64.egg/calcos/calcos.py", line 2856 in extractSpectrum
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/calcos-3.1.8-py3.5-linux-x86_64.egg/calcos/calcos.py", line 2788 in allScience
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/calcos-3.1.8-py3.5-linux-x86_64.egg/calcos/calcos.py", line 434 in calcos
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/calcos-3.1.8-py3.5-linux-x86_64.egg/calcos/calcos.py", line 211 in main
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/calcos-3.1.8-py3.5-linux-x86_64.egg/EGG-INFO/scripts/calcos", line 7 in <module>
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/setuptools-23.0.0-py3.5.egg/pkg_resources/__init__.py", line 1504 in run_script
  File "/home/jhunk/miniconda3/envs/astrobad/lib/python3.5/site-packages/setuptools-23.0.0-py3.5.egg/pkg_resources/__init__.py", line 719 in run_script
  File "/home/jhunk/miniconda3/envs/astrobad/bin/calcos", line 4 in <module>
loop.sh: line 13: 19691 Segmentation fault      python -q -X faulthandler `which calcos` -v -o out [filename here]