From 8bb9234031bcc377118b5c946a9e1495ecd6a44e Mon Sep 17 00:00:00 2001
From: Arthur Daussy <arthur.daussy@obeo.fr>
Date: Fri, 31 Jul 2026 12:09:30 +0200
Subject: [PATCH] ST6RI-961 Prevent duplicate implicit Subsettings for
 structurally equivalent feature chains

---
 .../org/omg/sysml/adapter/TypeAdapter.java    | 26 +++++++++-
 .../logic/TransitionUsageAdapterTest.java     | 51 +++++++++++++++++++
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/org.omg.sysml.logic/src/main/java/org/omg/sysml/adapter/TypeAdapter.java b/org.omg.sysml.logic/src/main/java/org/omg/sysml/adapter/TypeAdapter.java
index 281526b8a..8a794e940 100644
--- a/org.omg.sysml.logic/src/main/java/org/omg/sysml/adapter/TypeAdapter.java
+++ b/org.omg.sysml.logic/src/main/java/org/omg/sysml/adapter/TypeAdapter.java
@@ -327,7 +327,31 @@ public boolean isImplicitSpecializationDeclaredFor(EClass eClass) {
 	}
 	
 	public boolean isImplicitSpecializationFor(EClass eClass, Type general) {
-		return implicitGeneralTypes.getOrDefault(eClass, Collections.emptyList()).contains(general);
+		return implicitGeneralTypes.getOrDefault(eClass, Collections.emptyList()).stream().
+				anyMatch(existingGeneral->areEquivalentImplicitGeneralTypes(existingGeneral, general));
+	}
+
+	/**
+	 * Feature chains are derived Types for which object identity is not sufficient:
+	 * two independently created chains may represent the same ordered sequence of
+	 * chaining Features.
+	 */
+	protected static boolean areEquivalentImplicitGeneralTypes(Type first, Type second) {
+		if (first == second) {
+			return true;
+		} else if (first instanceof Feature && second instanceof Feature) {
+			List<Feature> firstChain = ((Feature)first).getChainingFeature();
+			List<Feature> secondChain = ((Feature)second).getChainingFeature();
+			if (!firstChain.isEmpty() && firstChain.size() == secondChain.size()) {
+				for (int i = 0; i < firstChain.size(); i++) {
+					if (firstChain.get(i) != secondChain.get(i)) {
+						return false;
+					}
+				}
+				return true;
+			}
+		}
+		return false;
 	}
 	
 	protected static boolean hasNoConformingSpecializations(Type type, Class<?> kind, Type defaultGeneral) {
diff --git a/org.omg.sysml.logic/src/test/java/org/omg/sysml/logic/TransitionUsageAdapterTest.java b/org.omg.sysml.logic/src/test/java/org/omg/sysml/logic/TransitionUsageAdapterTest.java
index e281101e6..bfe826cac 100644
--- a/org.omg.sysml.logic/src/test/java/org/omg/sysml/logic/TransitionUsageAdapterTest.java
+++ b/org.omg.sysml.logic/src/test/java/org/omg/sysml/logic/TransitionUsageAdapterTest.java
@@ -21,15 +21,26 @@
 
 package org.omg.sysml.logic;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+import java.util.List;
 
 import org.junit.Test;
+import org.omg.sysml.lang.sysml.AcceptActionUsage;
 import org.omg.sysml.lang.sysml.Feature;
 import org.omg.sysml.lang.sysml.FeatureDirectionKind;
 import org.omg.sysml.lang.sysml.ParameterMembership;
+import org.omg.sysml.lang.sysml.ReferenceUsage;
 import org.omg.sysml.lang.sysml.SysMLFactory;
 import org.omg.sysml.lang.sysml.SysMLPackage;
+import org.omg.sysml.lang.sysml.TransitionFeatureKind;
+import org.omg.sysml.lang.sysml.TransitionFeatureMembership;
 import org.omg.sysml.lang.sysml.TransitionUsage;
+import org.omg.sysml.lang.sysml.Type;
+import org.omg.sysml.util.FeatureUtil;
+import org.omg.sysml.util.TypeUtil;
 
 /**
  * Tests transition derived-property computations.
@@ -54,4 +65,44 @@ public void transitionSourceDerivationIsReentrantSafeWithoutSuccession() {
 		transition.getOwnedRelationship().add(parameterMembership);
 		assertNull(transition.getSource());
 	}
+
+	/**
+	 * A structurally equivalent feature chain already registered as an implicit
+	 * Subsetting must not be duplicated when the transition payload default
+	 * general type is computed.
+	 */
+	@Test
+	public void transitionPayloadDoesNotDuplicateEquivalentImplicitSubsetting() {
+		SysMLLogicStandaloneSetup.doSetup();
+		SysMLPackage.eINSTANCE.eClass();
+		SysMLFactory factory = SysMLFactory.eINSTANCE;
+		TransitionUsage transition = factory.createTransitionUsage();
+		addParameter(transition, factory.createReferenceUsage());
+		ReferenceUsage transitionPayload = factory.createReferenceUsage();
+		addParameter(transition, transitionPayload);
+
+		AcceptActionUsage trigger = factory.createAcceptActionUsage();
+		ReferenceUsage triggerPayload = factory.createReferenceUsage();
+		addParameter(trigger, triggerPayload);
+		TransitionFeatureMembership triggerMembership = factory.createTransitionFeatureMembership();
+		triggerMembership.setKind(TransitionFeatureKind.TRIGGER);
+		triggerMembership.getOwnedRelatedElement().add(trigger);
+		transition.getOwnedRelationship().add(triggerMembership);
+
+		Feature existingChain = FeatureUtil.chainFeatures(trigger, triggerPayload);
+		TypeUtil.addImplicitGeneralTypeTo(transitionPayload, SysMLPackage.Literals.SUBSETTING, existingChain);
+
+		TypeUtil.getImplicitGeneralTypesFor(transitionPayload);
+
+		List<Type> implicitSubsettings = TypeUtil.getImplicitGeneralTypesOnly(transitionPayload, SysMLPackage.Literals.SUBSETTING);
+		assertEquals(1, implicitSubsettings.size());
+		assertSame(existingChain, implicitSubsettings.get(0));
+	}
+
+	private static void addParameter(Type owner, Feature parameter) {
+		parameter.setDirection(FeatureDirectionKind.IN);
+		ParameterMembership membership = SysMLFactory.eINSTANCE.createParameterMembership();
+		membership.setOwnedMemberParameter(parameter);
+		owner.getOwnedRelationship().add(membership);
+	}
 }