Unexpected results when comparing two untangle.Element objects with the == operator

[amorimlb]

Recently I had to check whether an item in a list of untangle.Element was inside a second list using the in operator. Turns out the result was very misleading: Note: I know I shouldn't initialise an untangle.Element object like this (in my real life code I am using untangle.parse('file.xml') which creates a list of various untangle.Element), but this is the smallest syntactically correct code I could supply for this illustration.

import untangle
a = untangle.Element('a', '1')
b = untangle.Element('b', '1')
listA = [a, b]
c = untangle.Element('c', '1')
print(c in listA)

This prints True, but should print False as it does in:

a = object()
b = object()
listA = [a, b]
c = object()
print(c in listA)

So, since the in operator uses == to compare items, I thought it could be a problem with how == is being implemented in the Element class, which I think I confirmed by running:

import untangle
a = untangle.Element('a', '1')
b = untangle.Element('b', '1')
print(a == b)

This prints out True, but should print False, as this other code does:

a = object()
b = object()
print(a == b)

Using Python 3.6.8 and untangle 1.1.1 @adijbr contributed to these tests and bug report. Thanks!

[stchris]

You are right about this. The problem stems from the fact that untangle tries to be clever, so you can say object.attribute == "Foo".

I will have to think about how to fix this, if it is even possible without major breaking changes.

[amorimlb]

Ok, thanks for letting me know.

Lucas Amorim

On 18 Nov 2019, at 15:56, Christian Stefanescu notifications@github.com wrote:

You are right about this. The problem stems from the fact that untangle tries to be clever, so you can say object.attribute == "Foo".

I will have to think about how to fix this, if it is even possible without major breaking changes.

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