Reject duty-only properties on non-Duty rules

dprod-contracts/docs/specification.md

@@ -209,7 +209,7 @@ All five properties are `owl:ObjectProperty`. Their values come from open SKOS t
 | Property | Value |
 |----------|-------|
 | **Type** | `owl:DatatypeProperty` |
-| **Domain** | `odrl:Duty` |
+| **Subject scope** | `odrl:Duty` (enforced by SHACL; no `rdfs:domain`) |
 | **Range** | `xsd:dateTime` | `xsd:duration` (enforced by SHACL) |
 | **Cardinality** | 0..1 |
 | **Definition** | Time constraint for duty fulfillment |
@@ -350,7 +350,7 @@ ODRL defines `odrl:and` and `odrl:or` but lacks negation. DPROD Contracts adds `
 |----------|-------|
 | **Type** | `owl:ObjectProperty` |
 | **SubPropertyOf** | `odrl:function` |
-| **Domain** | `odrl:Duty` |
+| **Subject scope** | `odrl:Duty` (enforced by SHACL; no `rdfs:domain`) |
 | **Range** | `odrl:Party` |
 | **Cardinality** | 0..1 |
 | **Definition** | Party bearing the duty (must perform the action) |
@@ -363,7 +363,7 @@ The duty bearer. Replaces `odrl:assignee` on duties to avoid role overloading --
 |----------|-------|
 | **Type** | `owl:ObjectProperty` |
 | **SubPropertyOf** | `odrl:function` |
-| **Domain** | `odrl:Duty` |
+| **Subject scope** | `odrl:Duty` (enforced by SHACL; no `rdfs:domain`) |
 | **Range** | `odrl:Party` |
 | **Cardinality** | 0..1 |
 | **Definition** | Party affected by the duty action |
@@ -403,6 +403,7 @@ Shapes are defined in `dprod-contracts-shapes.ttl`. Key constraints:
 | `dprod-shapes:PermissionShape` | `odrl:Permission` | Exactly one `odrl:action`; at most one `odrl:target` (inherited from policy if absent) |
 | `dprod-shapes:ProhibitionShape` | `odrl:Prohibition` | Exactly one `odrl:action`; at most one `odrl:target` (inherited from policy if absent) |
 | `dprod-shapes:DutyShape` | `odrl:Duty` | Exactly one `odrl:action`; `dprod:subjectOfDuty` 0..1; `dprod:objectOfDuty` 0..1; `deadline` 0..1 (dateTime/duration); `schedule` 0..1 (identified `dprod:Schedule`); `state` 0..1 |
+| `dprod-shapes:DutyOnlyPropertySubjectShape` | Subjects using `dprod:deadline`, `dprod:subjectOfDuty`, or `dprod:objectOfDuty` | Subject must be an `odrl:Duty`; Permission and Prohibition use fails validation instead of inferring an additional Duty type |
 
 ### Schedule shapes
 
@@ -502,4 +503,4 @@ DPROD contracts reject odrl:Request because Offer-Request-Agreement semantics ar
 
 ---
 
-**Version**: 0.7 | **Date**: 2026-08-12
+**Version**: 0.7 | **Date**: 2026-08-19

dprod-contracts/dprod-contracts-shapes.ttl

@@ -23,7 +23,7 @@ dprod-shapes:
   rdfs:comment
     "This is intended to be used with SHACL, not as an ontology: the ontology element is to provide the metadata for the set of shapes."@en ;
   dct:license <https://creativecommons.org/licenses/by/4.0/> ;
-  dct:modified "2026-08-12"^^xsd:date ;
+  dct:modified "2026-08-19"^^xsd:date ;
   owl:imports <https://www.omg.org/spec/DPROD/contracts/> ;
   owl:imports sh: ;
   owl:versionInfo "0.7" ;
@@ -210,6 +210,27 @@ dprod-shapes:ProhibitionShape
   ] ;
 .
 
+dprod-shapes:DutyOnlyPropertySubjectShape
+  a sh:NodeShape ;
+  rdfs:isDefinedBy dprod-shapes: ;
+  rdfs:label "duty-only property subject shape" ;
+  sh:targetSubjectsOf dprod:deadline ;
+  sh:targetSubjectsOf dprod:subjectOfDuty ;
+  sh:targetSubjectsOf dprod:objectOfDuty ;
+  sh:and (
+    [ sh:class odrl:Duty ]
+    [
+      sh:not [
+        sh:or (
+          [ sh:class odrl:Permission ]
+          [ sh:class odrl:Prohibition ]
+        )
+      ]
+    ]
+  ) ;
+  sh:message "dprod:deadline, dprod:subjectOfDuty, and dprod:objectOfDuty may be used only on odrl:Duty." ;
+.
+
 dprod-shapes:DutyShape
   a sh:NodeShape ;
   rdfs:isDefinedBy dprod-shapes: ;

dprod-contracts/dprod-contracts.ttl

@@ -45,7 +45,7 @@ dct:modified a owl:AnnotationProperty .
     can partially understand them; DPROD-aware processors handle the
     extensions."""@en ;
   dct:license <https://creativecommons.org/licenses/by/4.0/> ;
-  dct:modified "2026-08-12"^^xsd:date ;
+  dct:modified "2026-08-19"^^xsd:date ;
   dct:publisher <https://www.omg.org/> ;
   dct:contributor <https://www.linkedin.com/in/matthiasautrata> ;
   dct:contributor <https://www.linkedin.com/in/natasavaritimou> ;
@@ -259,9 +259,10 @@ dprod:deadline
     - xsd:duration: relative to activation (e.g., P30D, PT24H)
     For duration: deadline = activationTime + duration.
     No rdfs:range declared because the range is a union of datatypes;
-    SHACL enforces the allowed types."""@en ;
+    SHACL enforces both the odrl:Duty subject scope and the allowed types.
+    No rdfs:domain is declared so invalid use does not silently infer an
+    additional odrl:Duty type."""@en ;
   rdfs:isDefinedBy dprod: ;
-  rdfs:domain odrl:Duty ;
   rdfs:label "deadline" ;
 .
 
@@ -370,10 +371,11 @@ dprod:subjectOfDuty
   a owl:ObjectProperty ;
   dct:description "Party bearing the duty (must perform the action)."@en ;
   rdfs:comment
-    "The duty bearer. Sub-property of odrl:function for ODRL processor compatibility."@en ;
+    """The duty bearer. Sub-property of odrl:function for ODRL processor
+    compatibility. SHACL enforces the odrl:Duty subject scope; no rdfs:domain
+    is declared so invalid use does not silently infer an odrl:Duty type."""@en ;
   rdfs:isDefinedBy dprod: ;
   rdfs:subPropertyOf odrl:function ;
-  rdfs:domain odrl:Duty ;
   rdfs:range odrl:Party ;
   rdfs:label "subject" ;
 .
@@ -382,10 +384,12 @@ dprod:objectOfDuty
   a owl:ObjectProperty ;
   dct:description "Party affected by the duty action."@en ;
   rdfs:comment
-    "The party affected by or receiving the result of the duty action. Sub-property of odrl:function for ODRL processor compatibility."@en ;
+    """The party affected by or receiving the result of the duty action.
+    Sub-property of odrl:function for ODRL processor compatibility. SHACL
+    enforces the odrl:Duty subject scope; no rdfs:domain is declared so invalid
+    use does not silently infer an odrl:Duty type."""@en ;
   rdfs:isDefinedBy dprod: ;
   rdfs:subPropertyOf odrl:function ;
-  rdfs:domain odrl:Duty ;
   rdfs:range odrl:Party ;
   rdfs:label "object" ;
 .

dprod-contracts/tests/test_duty_only_properties.py

@@ -0,0 +1,157 @@
+from pathlib import Path
+import unittest
+
+from pyshacl import validate
+from rdflib import Graph, Namespace
+from rdflib.namespace import RDFS
+
+
+CONTRACTS_DIR = Path(__file__).resolve().parents[1]
+ONTOLOGY_FILE = CONTRACTS_DIR / "dprod-contracts.ttl"
+SHAPES_FILE = CONTRACTS_DIR / "dprod-contracts-shapes.ttl"
+SPECIFICATION_FILE = CONTRACTS_DIR / "docs" / "specification.md"
+DPROD = Namespace("https://www.omg.org/spec/DPROD/dprod/")
+
+DUTY_ONLY_MESSAGE = (
+    "dprod:deadline, dprod:subjectOfDuty, and dprod:objectOfDuty "
+    "may be used only on odrl:Duty."
+)
+
+
+class DutyOnlyPropertyValidationTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls.ontology = Graph().parse(ONTOLOGY_FILE, format="turtle")
+        cls.shapes = Graph().parse(SHAPES_FILE, format="turtle")
+
+    def validate(self, statements: str, with_ontology: bool):
+        data = Graph().parse(
+            data=f"""
+                @prefix dprod: <https://www.omg.org/spec/DPROD/dprod/> .
+                @prefix dct: <http://purl.org/dc/terms/> .
+                @prefix ex: <https://example.org/> .
+                @prefix odrl: <http://www.w3.org/ns/odrl/2/> .
+                @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+                {statements}
+            """,
+            format="turtle",
+        )
+        if with_ontology:
+            return validate(
+                data_graph=data,
+                shacl_graph=self.shapes,
+                ont_graph=self.ontology,
+                inference="rdfs",
+                advanced=True,
+            )
+        return validate(
+            data_graph=data,
+            shacl_graph=self.shapes,
+            advanced=True,
+        )
+
+    def assert_conforms(self, statements: str) -> None:
+        for with_ontology in (True, False):
+            with self.subTest(with_ontology=with_ontology):
+                conforms, _, report = self.validate(statements, with_ontology)
+                self.assertTrue(conforms, report)
+
+    def assert_rejected(self, statements: str, message: str) -> None:
+        for with_ontology in (True, False):
+            with self.subTest(with_ontology=with_ontology):
+                conforms, _, report = self.validate(statements, with_ontology)
+                self.assertFalse(conforms, report)
+                self.assertIn(message, report)
+
+    def test_owl_domains_do_not_infer_duty_as_a_validation_fallback(self) -> None:
+        for duty_only_property in (
+            DPROD.deadline,
+            DPROD.subjectOfDuty,
+            DPROD.objectOfDuty,
+        ):
+            with self.subTest(duty_only_property=duty_only_property):
+                self.assertEqual(
+                    [],
+                    list(self.ontology.objects(duty_only_property, RDFS.domain)),
+                )
+
+    def test_specification_documents_shacl_enforced_duty_scope(self) -> None:
+        specification = SPECIFICATION_FILE.read_text(encoding="utf-8")
+
+        self.assertGreaterEqual(
+            specification.count(
+                "| **Subject scope** | `odrl:Duty` (enforced by SHACL; no `rdfs:domain`) |"
+            ),
+            3,
+        )
+        self.assertIn("dprod-shapes:DutyOnlyPropertySubjectShape", specification)
+
+    def test_duty_only_properties_are_rejected_on_other_rule_types(self) -> None:
+        property_values = {
+            "dprod:deadline": '"PT1H"^^xsd:duration',
+            "dprod:subjectOfDuty": "ex:provider",
+            "dprod:objectOfDuty": "ex:consumer",
+        }
+        for rule_class in ("odrl:Permission", "odrl:Prohibition"):
+            for property_name, value in property_values.items():
+                with self.subTest(rule_class=rule_class, property_name=property_name):
+                    self.assert_rejected(
+                        f"""
+                        ex:rule a {rule_class} ;
+                            odrl:action odrl:use ;
+                            {property_name} {value} .
+                        ex:provider a odrl:Party .
+                        ex:consumer a odrl:Party .
+                        """,
+                        DUTY_ONLY_MESSAGE,
+                    )
+
+    def test_named_and_inline_duties_remain_valid(self) -> None:
+        duty_properties = """
+            odrl:action odrl:use ;
+            dprod:deadline "PT1H"^^xsd:duration ;
+            dprod:subjectOfDuty ex:provider ;
+            dprod:objectOfDuty ex:consumer
+        """
+        self.assert_conforms(
+            f"""
+            ex:namedDuty a odrl:Duty ;
+                {duty_properties} .
+            [ a odrl:Duty ;
+                {duty_properties}
+            ] .
+            ex:provider a odrl:Party .
+            ex:consumer a odrl:Party .
+            """
+        )
+
+    def test_obsolete_recurrence_is_rejected_on_every_rule_type(self) -> None:
+        for rule_class in ("odrl:Duty", "odrl:Permission", "odrl:Prohibition"):
+            with self.subTest(rule_class=rule_class):
+                self.assert_rejected(
+                    f"""
+                    ex:rule a {rule_class} ;
+                        odrl:action odrl:use ;
+                        dprod:recurrence "FREQ=DAILY" .
+                    """,
+                    "dprod:recurrence is obsolete; use dprod:schedule",
+                )
+
+    def test_schedule_remains_valid_on_non_duty_resources(self) -> None:
+        self.assert_conforms(
+            '''
+            ex:permission a odrl:Permission ;
+                odrl:action odrl:use ;
+                dprod:schedule ex:weekdaySchedule .
+
+            ex:weekdaySchedule a dprod:Schedule ;
+                dct:conformsTo dprod:PosixCrontabScheduleFormat ;
+                dprod:scheduleTimeZone "Europe/London" ;
+                dprod:scheduleExpression "0 6 * * 1-5" .
+            '''
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()