Allow duplicates in rdf:List

[wwaites]

The check causing the problem in #223 is incorrect. This addresses the first half of the issue, allowing duplicates in lists. It does not address closing the list.

[gromgull]

The closing the list issue is less important. It's now always closed. Leaving an open list is a very special case, people who want that can probably fix it themselves.

[wwaites]

Coveralls seems a bit confused. Removing code and adding a test should only increase test coverage!

[gromgull]

Actually - I find coveralls almost completely useless - we should just remove it :)

[wwaites]

Seems so. Anyhow, are you satisfied that this is the right thing to do? Should I merge it?

[gromgull]

The check was added to avoid an infinite loop in cases of degenerate lists I guess, but it's totally misguided, since it checks for duplicate values, not duplicate list elements.

The correct (?) test is here: https://github.com/RDFLib/rdflib/blob/master/rdflib/graph.py#L801-L802

The whole __len__ method could then just be len(list(self.graph.items(self.uri))) ?

[wwaites]

Yes, you're correct of course. Would have been obvious if I had changed the test to do

assert len(c) == 3

now done.

[gromgull]

👍 Thanks!