ifctester: two false passes in prohibited property checks

[BIMvoice]

Two distinct false passes in Property.__call__'s prohibited branch. Both let a violation report as compliant, which is the worst direction for a checker to be wrong in, since nothing prompts anyone to look again.

1. Present but empty looks absent

Property.__call__ filters empty string values out before deciding whether the property exists:

elif prop is not None and prop != "":
    props[pset_name][self.baseName] = prop

then the prohibited branch reuses that filtered result. So a property that is present but empty looks absent, and a prohibited requirement silently passes.

property-facet.md is explicit that a prohibited property must not exist even if empty. That filtering is correct for REQUIRED and OPTIONAL, which legitimately treat empty as not populated, and reusing it for prohibited is what inverts a violation into a pass.

This is the Property sibling of #9273, which fixed the same shape in Attribute.

2. Cross-pset masking when a value is required

A separate bug in the same branch, only when value is set. With a pattern propertySet matching several psets, the loop shared one is_pass accumulator across all of them. An earlier pset lacking the property, or holding a mismatching value, drove is_pass to False permanently. A later pset holding exactly the prohibited value never flipped it back, because a value match only left is_pass unchanged rather than setting it.

Proven distinct rather than a restatement: tested against this PR's own previous head, with the fix for defect 1 already in place, and it still failed identically.

Fixed by checking each matching pset independently, split cleanly on whether self.value is set, so the two guards together cover every prohibited case before the shared loop runs. It reuses the existing single-pset value, dataType and unit matching by probing a shallow copy rather than duplicating that logic, which leaves the main loop untouched.

Sibling sweep

Every facet with a cardinality branch, not just this one:

facet	existence check	affected
Attribute	filtered before check	yes, fixed in #9273
Property	filtered before check	yes, this PR
Classification	bool(references), no filtering	no, already correct
PartOf	is not None on relationship objects	no
Material	is not None from get_material	no
Entity	class name match, no value concept	not applicable

Classification is the reference pattern: existence is checked before any filtering.

Overlap with other open PRs

• fix(ifctester): allow IFCLOGICAL properties with UNKNOWN value to pass existence check #8161 by @gernotluidolt: no overlap. It changes a line inside the block these guards return before.
• ifctester: fix four wrong-verdict defects #9190: no textual conflict, but related. It fixes the same "shared accumulator masks per-pset truth" class in the optional branch's escape hatch. Whoever merges should know they are sibling fixes to the same method.
• ifctester: fix bounded property restriction checks #9250: no conflict, its change is inside the IfcPropertyBoundedValue handling further down.
• Clean against ifctester: IFC2X3 predefined psets crash, and two Classification false verdicts #9059, ifctester: PartOf false pass on USERDEFINED predefinedType #9203, ifctester: Attribute optional cardinality and LOGICAL UNKNOWN give wrong verdicts #9205, ifctester: fix crash on IFC2X3 material properties #9261, ifctester: tolerance is missing its fixed component #9263, ifctester: wrong-case boolean enum matches anything #9268, ifctester: PartOf group and containment do not recurse #9272, ifctester: prohibited attribute passes when empty #9273, with a control pair confirming the check detects real conflicts.

Tests

Two fixture directories, property_prohibited_empty_string/ and property_prohibited_multi_pset/, each with its own test file. test_facet.py deliberately untouched, since several of our other open ifctester PRs already modify it.

Red before each fix, failing for the right reason in both cases:

test_empty_string_foo_property_fails_the_prohibition FAILED
E       assert True is False

test_a_later_matching_pset_with_the_value_fails_the_prohibition FAILED
E       assert True is False

Green after. Full ifctester suite 43/43.

Produced with AI assistance.