Importing defusedxml.ElementTree

[brunato]

Importing defusedxml.ElementTree before xml.etree.ElementTree cause the C optimized version (_elementtree) to not load:

>>> import defusedxml.ElementTree
>>> import xml.etree.ElementTree as ET
>>> ET.Element is ET._Element_Py
True

Viceversa works as expected:

>>> import xml.etree.ElementTree as ET
>>> import defusedxml.ElementTree
>>> ET.Element is ET._Element_Py
False

Best,
Davide

[tiran]

This is by design. defusedxml cannot patch C code, therefore it has to disable the C extension.

[brunato]

Only to report that, despite in the code there is a restore of the original module:

defusedxml/defusedxml/ElementTree.py

Lines 43 to 49 in f2c7c35

	sys.modules[cmodname] = None
	pure_pymod = importlib.import_module(pymodname)
	if cmod is not None:
	sys.modules[cmodname] = cmod
	else:
	sys.modules.pop(cmodname)
	sys.modules[pymodname] = pymod

anyway something weird happens, because sys.modules contains the original ElementTree module with C optimizations but the import statement returns the pure Python version:

$ python
Python 3.6.6 (default, Jul 19 2018, 14:25:17) 
[GCC 8.1.1 20180712 (Red Hat 8.1.1-5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import defusedxml.ElementTree
>>> etmod = sys.modules['xml.etree.ElementTree']
>>> etmod.Element is etmod._Element_Py
False
>>> import xml.etree.ElementTree as ET
>>> ET.Element is ET._Element_Py
True
>>> ET is etmod
False
>>> import importlib
>>> etmod is importlib.import_module('xml.etree.ElementTree')
True
>>> 

Thanks,
Davide