Eryk Sun <eryk...@gmail.com> added the comment:
ctypes.windll is an instance of ctypes.LibraryLoader, which has a __getattr__
method that calls ctypes.WinDLL(name) and caches the result as an instance
attribute. I suppose with chained exceptions it's reasonable to handle OSError
in __getattr__ by raising AttributeError. For example:
class A:
def __init__(self, name):
raise OSError
class B:
def __getattr__(self, name):
try:
A(name)
except OSError:
raise AttributeError
Demo:
>>> b = B()
>>> b.test
Traceback (most recent call last):
File "<stdin>", line 4, in __getattr__
File "<stdin>", line 3, in __init__
OSError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 6, in __getattr__
AttributeError
>>> hasattr(b, 'test')
False
FYI, I recommend avoiding the cdll and windll LibraryLoader instances. I wish
they were deprecated because globally caching CDLL and WinDLL instances leads
to conflicts between projects that use the same shared libraries.
----------
nosy: +eryksun
stage: -> test needed
versions: +Python 3.8
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<https://bugs.python.org/issue34816>
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