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TestCase pass-specification_optionality_and_facet_optionality_can_be_combined not passes #402
Description
description
the TestCase form the folder ids with the regarding files:
- pass-specification_optionality_and_facet_optionality_can_be_combined not passes.ifc and
- pass-specification_optionality_and_facet_optionality_can_be_combined not passes.ids
not pass with the usage of ifcTester. From my understanding (based on https://github.com/buildingSMART/IDS/blob/development/Documentation/ImplementersDocumentation/TestCases/scripts.md) this TestCase should pass fully.
used python script
import ifcopenshell
import ifctester
import ifctester.ids
import ifctester.reporter
import webbrowser
model = ifcopenshell.open('pass-specification_optionality_and_facet_optionality_can_be_combined.ifc')
my_ids = ifctester.ids.open('pass-specification_optionality_and_facet_optionality_can_be_combined.ids')
my_ids.validate(model)
# return the check of specifications pass(true) or fail(false) with
# and the name of the specification
# and if all specifications of one IDS pass
all_spec_pass = True
for spec in my_ids.specifications:
print("name: {}, passed: {}".format(spec.name, spec.status))
if not spec.status:
all_spec_pass = False
print(">>>>>> ")
print("all checks of the specifications of this IDS pass: {}".format(all_spec_pass))
# for check the results of return above
ifctester.reporter.Console(my_ids).report()return
name: Specification optionality and facet optionality can be combined, passed: False
>>>>>>
all checks of the specifications of this IDS pass: False
Specification optionality and facet optionality can be combined
[FAIL] (0/1) Specification optionality and facet optionality can be combined
Applies to:
All IFCWALL data
Requirements:
The Name shall be Waldo
The Description may be Foobar
The attribute value None is empty - #1=IfcWall('1hqIFTRjfV6AWq_bMtnZwI',$,'Waldo',$,$,$,$,$,$)
setup
python: 3.11
ifctester: 0.8.1
ifcopenshell: 0.7.0.240627
os: PopOS
Activity
Moult commentedon Mar 11, 2025
This is not a bug in IDS? I'm closing this referencing it here: IfcOpenShell/IfcOpenShell#6323
Moult commentedon Feb 16, 2026
Reopening because I think this is potentially a bug in IDS itself. The test case says it should pass
pass-specification_optionality_and_facet_optionality_can_be_combined not passes.ifc, however, the written documentation seems to contradict.https://github.com/buildingSMART/IDS/blob/development/Documentation/UserManual/attribute-facet.md states for prohibited facets:
And for optional it says:
From this, the word "exists" seems to mean is part of the schema definition, and has nothing to do with emptiness. Therefore, I'd say that the test case should fail, not pass.
BIMvoice commentedon Aug 6, 2026
Measured this rather than re-reading the spec text in isolation.
On the reported behaviour, optional plus an unset
Descriptionfailing instead of passing: that is an implementation bug on our side, and there is already an unmerged fix for it, IfcOpenShell#7645 by @louistrue.On the reopening question, we do not think this is an IDS bug.
attribute-facet.md's REQUIRED with no value row defines populated as "not null". Reading OPTIONAL's "exists" any other way, as schema level presence, would make that word mean two different things one table row apart.property-facet.md's OPTIONAL row makes the intended reading explicit: "Lack of property is allowed."So the fixture's PASS expectation matches the documented behaviour, and the current FAIL is the implementation, not the test case.
Separately, the same investigation turned up a related defect on the PROHIBITED row, which seems worth recording here since it comes from the same table.
That row says the attribute must not exist, even if empty. We were not enforcing the "even if empty" half:
The cause is that empty values are stripped out before existence is decided, which is right for REQUIRED and OPTIONAL but makes a present-but-empty attribute indistinguishable from an absent one. Notably the
Classificationfacet does not do that stripping and was already correct, so the three facets did not agree with each other.Fixed on our side in IfcOpenShell#9273. Not proposing any specification change, the documentation was already clear on this. Flagging it only because the same "even if empty" phrasing appears in
attribute-facet.md,property-facet.mdandclassification-facet.md, so other implementations may want to check the same case.