infixowl cardinality - 0

[MattyCrowther]

owl.Restriction(property,graph=graph,cardinality=Literal(0)) Raises an error.
assert len(validRestrProps)
When cardinality value is given as 0.

This comes from:

  validRestrProps = [(i, oTerm) for (i, oTerm) in restrTypes if i]
  assert len(validRestrProps)

I believe this is an oversight as if i == 0 returns False.
However, I believe cardinality: 0 is valid.

[ghost]

owl.Restriction(property,graph=graph,cardinality=Literal(0)) Raises an error. assert len(validRestrProps) When cardinality value is given as 0.

I believe this is an oversight as if i == 0 returns False. However, I believe cardinality: 0 is valid.

You are spot on, it's a classic example of "falsiness", offending LoC is:

rdflib/rdflib/extras/infixowl.py

Line 1652 in 6ed2ef4

validRestrProps = [(i, oTerm) for (i, oTerm) in restrTypes if i]

and the obvious change to if i is not None fixes the issue, thanks for spotting it and nailing the cause.

PR #1530 raised.