I am puzzled with the following case which result in failing execution in python 2.7.10:
from distutils.version import LooseVersion
class A(object):
def __init__(self, field1):
self.field1 = field1
a_instance = A('A')
version_tag = LooseVersion('5.0.0')
test1 = ['a', 1, [2,3,4], version_tag, a_instance]
print 1 in test1 # True
print a_instance in test1 # AttributeError: 'A' object has no attribute 'version'
print test1.__contains__(a_instance) # AttributeError: 'A' object has no attribute 'version'
However this works:
test1 = ['a', 1, [2,3,4], a_instance, version_tag]
print 1 in test1 # True
print a_instance in test1 # True
print test1.__contains__(a_instance) # True
I know how to fix the issue on my side but I fail to understand why LooseVersion is affecting the "contain" test. Could anyone explain?
(By the way this is also the case with StrictVersion)
The problem can be narrowed to
a_instance == version_tag
(__contains__ has to compare every element until it finds a match)
Unfortunately LooseVersion just can't compare to other objects.