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I’ve just found a weirdness with `InterpreterConst...
# development
a
I’ve just found a weirdness with 
InterpreterConstraints
with respect to how it orders inputs. Can someone help me understand what the correct behaviour should be here? (test case will appear in thread)
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def test_ic_ordering():
    
    inputs = ["CPython==2.7.*", "PyPy", "CPython>=3.6,<4,!=3.7.*"]
    a = InterpreterConstraints(inputs)
    a_str = [str(i) for i in a]
    b = InterpreterConstraints(a_str)

    print(inputs)
    print(a)
    print(a_str)
    print(b) 

    assert a == b
which gives the following output:
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['CPython==2.7.*', 'PyPy', 'CPython>=3.6,<4,!=3.7.*']
CPython==2.7.* OR CPython!=3.7.*,<4,>=3.6 OR PyPy
['CPython==2.7.*', 'CPython!=3.7.*,<4,>=3.6', 'PyPy']
CPython!=3.7.*,<4,>=3.6 OR CPython==2.7.* OR PyPy
I think the issue arises from the constructor, which I think is a bit too eager to do things without assigning any variables
h
The weird part being how 
a != b
, right? Weird. It should be sorting the inputs
a
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super().__init__(
            v if isinstance(v, Requirement) else self.parse_constraint(v)
            for v in sorted(constraints, key=lambda c: str(c))
        )
I think the correct behaviour is to convert the list into 
Requirement
objects, and then do the sort, rather than sorting on the heterogeneous constraints
h
ah yeah that makes sense, good catch. That would be great to fix in a dedicated PR w/ a test like you have above
a
Easy
@hundreds-father-404 My fix breaks a test you wrote recently for poetry constraints. Are you OK with me changing the expected test output here, or would you prefer me to try to make both tests pass?
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E         '!=3.6.1,>=3.6 || ==2.7.*'  '==2.7.* || !=3.6.1,>=3.6'
(clearly 
parse_requirement
has its own internal ordering problem, which is what caused the parent issue)
h
yes you can fix 🙂 ordering doesn't matter for that test, only determinism
a
Figures. Thank you!
I’m guessing the root cause of the bug is that internal sorting that happens inside 
Requirement.parse
— so if you input a 
list[str]
, you’d sort the list before sorting the requirements inside the list, which would mean that initial list came out slightly unsorted. Wheee
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