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thliebig / openEMS

openEMS is a free and open-source electromagnetic field solver using the EC-FDTD method.
http://openEMS.de
GNU General Public License v3.0
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openEMS.pyx: check canonical path in assert, close #113. #114

Closed biergaizi closed 1 year ago

biergaizi commented 1 year ago

Currently, running openEMS's example Python scripts on macOS always fails with the following error:

$ python3 MSL_NotchFilter.py
Traceback (most recent call last):
  File "/Users/gentoo/code/openEMS-Project/openEMS/python/Tutorials/MSL_NotchFilter.py", line 103, in <module>
    FDTD.Run(Sim_Path, cleanup=True)
  File "openEMS/openEMS.pyx", line 489, in openEMS.openEMS.openEMS.Run
AssertionError

This is caused by an oversight of an assertion in openEMS.pyx:

os.chdir(sim_path)
# ...
assert os.getcwd() == sim_path

The problem here is that "sim_path" is not a canonical path name, so the assertion would fail if the path we're switching into contains a symbolic link. This problem affects all operating systems, it's not limited to macOS. But on macOS, the problem is especially serious, since macOS's "/tmp" is a link to "/private/tmp" by default. Thus, it causes an AssertionError in all the included Python examples.

Instead of doing assert os.getcwd() == sim_path, we should do assert os.getcwd() == os.path.realpath(sim_path) instead to ensure we're checking a canonical path in order to fix Issue #113.