toast.__init__ fails an exception

[keskitalo]

Should import toast fail, the exception handling seems to have some stale code that looks for file called RELEASE two levels higher than the root directory: https://github.com/hpc4cmb/toast/blob/master/src/toast/__init__.py#L24-L35

[tskisner]

That is not stale code- it is used installing the code with setup.py during generating the documentation on readthedocs.

[keskitalo]

Excellent. However, it still fails if there is any issue importing toast:

In [1]: import toast                                                                                                                                                               
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
~/Software/macports/lib/python3.7/site-packages/toast/__init__.py in <module>
     19 try:
---> 20     from ._libtoast import Environment
     21 

ImportError: dlopen(/Users/reijo/Software/macports/lib/python3.7/site-packages/toast/_libtoast.cpython-37m-darwin.so, 2): Symbol not found: __ZN3atm10AtmProfileC1ERKNS_6LengthERKNS_8PressureERKNS_11TemperatureEdRKNS_7PercentES3_S6_dS3_m
  Referenced from: /Users/reijo/Software/macports/lib/python3.7/site-packages/toast/_libtoast.cpython-37m-darwin.so
  Expected in: flat namespace
 in /Users/reijo/Software/macports/lib/python3.7/site-packages/toast/_libtoast.cpython-37m-darwin.so

During handling of the above exception, another exception occurred:

FileNotFoundError                         Traceback (most recent call last)
<ipython-input-1-548f5c417892> in <module>
----> 1 import toast

~/Software/macports/lib/python3.7/site-packages/toast/__init__.py in <module>
     31     thisdir = os.path.abspath(os.path.dirname(__file__))
     32     relfile = os.path.join(thisdir, "..", "..", "RELEASE")
---> 33     with open(relfile, "r") as rel:
     34         if __version__ is None:
     35             __version__ = rel.readline().rstrip()

FileNotFoundError: [Errno 2] No such file or directory: '/Users/reijo/Software/macports/lib/python3.7/site-packages/toast/../../RELEASE'

[tskisner]

Ok, we should have an additional try / except around parsing the RELEASE file and raise ImportError so that it propagates back to the calling code.

[tskisner]

This old issue was fixed some time ago in #350. If the compiled extension is not importable to get the version and also the RELEASE file is not readable, then it raises ImportError.