[2389] Add support of inheritance of subject in subject compartment

CHANGELOG.adoc

@@ -58,6 +58,7 @@ This removes Rollup warnings about missing global names for externalized peer de
 - https://github.com/eclipse-syson/syson/issues/2382[#2382] [diagrams] Add support of stakeholder inheritance in _stakeholders_ compartments of `RequirementUsage` and `RequirementDefinition` graphical nodes.
 - https://github.com/eclipse-syson/syson/issues/2387[#2387] [diagrams] Add support of objective requirement inheritance in _objective_ compartments of `CaseUsage` and `CaseDefinition` graphical nodes.
 - https://github.com/eclipse-syson/syson/issues/2391[#2391] [diagrams] Add support of actor inheritance in _actors_ compartment of `CaseDefinition` and `CaseUsage` graphical nodes.
+- https://github.com/eclipse-syson/syson/issues/2389[#2389] [diagrams] Add support of inheritance of subject in _subject_ compartment of `CaseDefinition` and `CaseUsage` (and more) graphical nodes.
 
 == v2026.7.0
 

backend/application/syson-application/src/test/java/org/eclipse/syson/application/controllers/diagrams/general/view/GVCompartmentItemInheritanceTests.java

@@ -1008,6 +1008,42 @@ public void checkActorInheritanceForConcernWithSpecialization(String subclassifi
                 .run();
     }
 
+    private static Stream<Arguments> subjectInheritanceParameters() {
+        return Stream.of(
+                Arguments.of("New Requirement Definition", "New Subclassification", SysmlPackage.eINSTANCE.getRequirementDefinition(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.REQUIREMENT_DEFINITION_ID),
+                Arguments.of("New Requirement", "New Redefinition", SysmlPackage.eINSTANCE.getRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.REQUIREMENT_USAGE_ID),
+                Arguments.of("New Requirement", "New Subsetting", SysmlPackage.eINSTANCE.getRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.REQUIREMENT_USAGE_ID),
+                Arguments.of("New Requirement", "New Reference Subsetting", SysmlPackage.eINSTANCE.getRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.REQUIREMENT_USAGE_ID),
+                Arguments.of("New Satisfy Requirement", "New Redefinition", SysmlPackage.eINSTANCE.getSatisfyRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.SATISFY_REQUIREMENT_USAGE_ID),
+                Arguments.of("New Satisfy Requirement", "New Subsetting", SysmlPackage.eINSTANCE.getSatisfyRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.SATISFY_REQUIREMENT_USAGE_ID),
+                Arguments.of("New Satisfy Requirement", "New Reference Subsetting", SysmlPackage.eINSTANCE.getSatisfyRequirementUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.SATISFY_REQUIREMENT_USAGE_ID),
+                Arguments.of("New Concern Definition", "New Subclassification", SysmlPackage.eINSTANCE.getConcernDefinition(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CONCERN_DEFINITION_ID),
+                Arguments.of("New Concern", "New Redefinition", SysmlPackage.eINSTANCE.getConcernUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CONCERN_USAGE_ID),
+                Arguments.of("New Concern", "New Subsetting", SysmlPackage.eINSTANCE.getConcernUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CONCERN_USAGE_ID),
+                Arguments.of("New Concern", "New Reference Subsetting", SysmlPackage.eINSTANCE.getConcernUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CONCERN_USAGE_ID),
+                Arguments.of("New Case Definition", "New Subclassification", SysmlPackage.eINSTANCE.getCaseDefinition(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CASE_DEFINITION_ID),
+                Arguments.of("New Case", "New Redefinition", SysmlPackage.eINSTANCE.getCaseUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CASE_USAGE_ID),
+                Arguments.of("New Case", "New Subsetting", SysmlPackage.eINSTANCE.getCaseUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CASE_USAGE_ID),
+                Arguments.of("New Case", "New Reference Subsetting", SysmlPackage.eINSTANCE.getCaseUsage(), GeneralViewWithTopNodesTestProjectData.GraphicalIds.CASE_USAGE_ID)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("subjectInheritanceParameters")
+    public void checkSubjectInheritanceWithSubclassification(String subclassifier, String specialization, EClass eClass, String baseElementNodeId) {
+        new ElementSpecializationInheritanceTestRunner()
+                .baseElementToInheritFromEClass(eClass)
+                .baseElementToInheritFromNodeId(baseElementNodeId)
+                .elementToInheritCreationToolName("New Subject")
+                .withSelectedElementId("")
+                .elementToInheritExpectedListItemLabelText("ref subject")
+                .compartmentName("subject")
+                .elementThatInheritFromBaseElementCreationToolName(subclassifier)
+                .elementThatInheritFromBaseElementEClass(eClass)
+                .specializationToolName(specialization)
+                .run();
+    }
+
     /**
      * This test runner verifies that creating a specializing relationship create inherited elements.
      *

backend/services/syson-diagram-services/src/main/java/org/eclipse/syson/diagram/services/InheritedCompartmentItemFilterSwitch.java

@@ -39,6 +39,7 @@
 import org.eclipse.syson.sysml.StakeholderMembership;
 import org.eclipse.syson.sysml.StateUsage;
 import org.eclipse.syson.sysml.Step;
+import org.eclipse.syson.sysml.SubjectMembership;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.eclipse.syson.sysml.Type;
 import org.eclipse.syson.sysml.Usage;
@@ -156,6 +157,10 @@ public Boolean casePartUsage(PartUsage object) {
             // We are dealing with an Actor
             // so the part usage is an actor if and only if, it is contained by a ActorMembership
             result = object.getOwningMembership() instanceof ActorMembership;
+        } else if (this.isSubjectReference()) {
+            // We are dealing with a subject
+            // so the reference usage is a subject if and only if, it is contained by a SubjectMembership
+            result = object.getOwningMembership() instanceof SubjectMembership;
         } else {
             EClassifier eType = this.eReference.getEType();
             EClass eClass = object.eClass();
@@ -218,13 +223,26 @@ public Boolean casePortUsage(PortUsage object) {
      */
     @Override
     public Boolean caseReferenceUsage(ReferenceUsage object) {
+        final boolean result;
         if (this.shouldConsiderParameter(object)) {
-            return this.isInheritedParameter(object);
+            result = this.isInheritedParameter(object);
+        } else if (this.isSubjectReference()) {
+            // We are dealing with a subject
+            // so the reference usage is a subject if and only if, it is contained by a SubjectMembership
+            result = object.getOwningMembership() instanceof SubjectMembership;
+        } else {
+            EClassifier eType = this.eReference.getEType();
+            EClass eClass = object.eClass();
+            result = eType.equals(eClass) || (eType instanceof EClass eTypeEClass && eTypeEClass.isSuperTypeOf(eClass));
         }
+        return result;
+    }
 
-        EClassifier eType = this.eReference.getEType();
-        EClass eClass = object.eClass();
-        return eType.equals(eClass) || (eType instanceof EClass eTypeEClass && eTypeEClass.isSuperTypeOf(eClass));
+    private boolean isSubjectReference() {
+        return this.eReference.equals(SysmlPackage.eINSTANCE.getRequirementUsage_SubjectParameter())
+                || this.eReference.equals(SysmlPackage.eINSTANCE.getRequirementDefinition_SubjectParameter())
+                || this.eReference.equals(SysmlPackage.eINSTANCE.getCaseDefinition_SubjectParameter())
+                || this.eReference.equals(SysmlPackage.eINSTANCE.getCaseUsage_SubjectParameter());
     }
 
     @Override
@@ -234,6 +252,10 @@ public Boolean caseRequirementUsage(RequirementUsage object) {
             // We are dealing with an objective
             // so the part usage is an objective if and only if, it is contained by an ObjectiveMembership
             result =  object.getOwningMembership() instanceof ObjectiveMembership;
+        } else if (this.isSubjectReference()) {
+            // We are dealing with a subject
+            // so the reference usage is a subject if and only if, it is contained by a SubjectMembership
+            result = object.getOwningMembership() instanceof SubjectMembership;
         } else {
             EClassifier eType = this.eReference.getEType();
             EClass eClass = object.eClass();

backend/views/syson-standard-diagrams-view/src/main/java/org/eclipse/syson/standard/diagrams/view/SDVDiagramDescriptionProvider.java

@@ -889,6 +889,14 @@ private List<IDiagramElementDescriptionProvider<?>> createCompartmentsForSubject
         compartmentNodeDescriptionProviders.add(new RequirementUsageSubjectCompartmentNodeDescriptionProvider(colorProvider, this.getDescriptionNameGenerator()));
         compartmentNodeDescriptionProviders.add(new CompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getRequirementUsage(), SysmlPackage.eINSTANCE.getRequirementUsage_SubjectParameter(),
                 colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getCaseDefinition(), SysmlPackage.eINSTANCE.getCaseDefinition_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getCaseUsage(), SysmlPackage.eINSTANCE.getCaseUsage_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getConcernDefinition(), SysmlPackage.eINSTANCE.getRequirementDefinition_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getConcernUsage(), SysmlPackage.eINSTANCE.getRequirementUsage_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getRequirementDefinition(), SysmlPackage.eINSTANCE.getRequirementDefinition_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getRequirementUsage(), SysmlPackage.eINSTANCE.getRequirementUsage_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+        compartmentNodeDescriptionProviders.add(new InheritedCompartmentItemNodeDescriptionProvider(SysmlPackage.eINSTANCE.getSatisfyRequirementUsage(), SysmlPackage.eINSTANCE.getRequirementUsage_SubjectParameter(), colorProvider, this.getDescriptionNameGenerator()));
+
 
         return compartmentNodeDescriptionProviders;
     }

doc/content/modules/user-manual/pages/release-notes/2026.9.0.adoc

@@ -17,6 +17,14 @@
 ** Add support of actor inheritance in _actors_ compartment of `CaseDefinition` and `CaseUsage` graphical nodes.
 The actor inheritance in _actors_ compartment is also visible in the following graphical nodes:
 
+*** `RequirementDefinition`
+*** `RequireUsage`
+*** `ConcernDefinition`
+*** `ConcernUsage`
+*** `SatisfyRequirementUsage`
+** Add support of subject inheritance in _subject_ compartment of `CaseDefinition` and `CaseUsage` graphical nodes.
+The subject inheritance in _subject_ compartment is also visible in the following graphical nodes:
+
 *** `RequirementDefinition`
 *** `RequireUsage`
 *** `ConcernDefinition`