[2419] Export the metadata of the ends of a connector declared inline

CHANGELOG.adoc

@@ -47,6 +47,8 @@ It is now _Become nested Concern_ instead of _Become nested Requirement_.
 Following KerML, where `endFeature` is defined as the owned features having `isEnd = true`, the ends owned through a plain `FeatureMembership` are now collected as well, and not only those owned through an `EndFeatureMembership`.
 This also fixes `relatedFeature`, `sourceFeature` and `targetFeature`, which were all empty for such connections.
 - https://github.com/eclipse-syson/syson/issues/2226[#2226] [import] Fix textual import of annotations on relationships so their `annotatedElement` is set and they are returned by `Element#getOwnedAnnotation()`.
+- https://github.com/eclipse-syson/syson/issues/2419[#2419] [export] Fix the export of the prefix metadata carried by the ends of a connector, which were dropped when those ends are declared inline.
+The ends of a connector created from a diagram are owned through an `EndFeatureMembership` and are exported inline, so their metadata, such as the `#original` and `#derive` of a requirement derivation, were lost.
 
 === Improvements
 

backend/application/syson-application/src/test/java/org/eclipse/syson/sysml/textual/SysMLElementSerializerTest.java

@@ -1680,6 +1680,51 @@ public void interfaceUsageWithNestedPortEnd() {
         this.assertTextualFormEquals("connection interface1 connect livingRoom.heater.socket to outlet;", interfaceUsage);
     }
 
+    @Test
+    public void connectionUsageWithMetadataOnItsEnds() {
+        PartUsage rootPart = this.builder.createWithName(PartUsage.class, "owner1");
+
+        PortUsage socket = this.builder.createInWithName(PortUsage.class, rootPart, "socket");
+        PortUsage outlet = this.builder.createInWithName(PortUsage.class, rootPart, "outlet");
+
+        InterfaceUsage interfaceUsage = this.builder.createWithName(InterfaceUsage.class, "interface1");
+        this.addAsFeatureMember(rootPart, interfaceUsage);
+
+        EndFeatureMembership sourceEnd = this.createConnectionEndFeatureMembership(socket);
+        this.applyMetadataOnEnd(sourceEnd, "original");
+        EndFeatureMembership targetEnd = this.createConnectionEndFeatureMembership(outlet);
+        this.applyMetadataOnEnd(targetEnd, "derive");
+        interfaceUsage.getOwnedRelationship().add(sourceEnd);
+        interfaceUsage.getOwnedRelationship().add(targetEnd);
+
+        this.assertTextualFormEquals("connection interface1 connect #original socket to #derive outlet;", interfaceUsage);
+    }
+
+    /**
+     * Applies a prefix metadata on the end owned by the given membership, the way {@code #original} and {@code #derive}
+     * are applied on the ends of a requirement derivation.
+     */
+    private void applyMetadataOnEnd(EndFeatureMembership endFeatureMembership, String metadataDefinitionName) {
+        MetadataDefinition metadataDefinition = this.fact.createMetadataDefinition();
+        metadataDefinition.setDeclaredName(metadataDefinitionName);
+
+        MetadataUsage metadataUsage = this.fact.createMetadataUsage();
+        OwningMembership owningMembership = this.fact.createOwningMembership();
+        owningMembership.getOwnedRelatedElement().add(metadataUsage);
+        owningMembership.setMemberElement(metadataUsage);
+
+        FeatureTyping featureTyping = this.fact.createFeatureTyping();
+        featureTyping.setType(metadataDefinition);
+        featureTyping.setTypedFeature(metadataUsage);
+        metadataUsage.getOwnedRelationship().add(featureTyping);
+
+        endFeatureMembership.getOwnedRelatedElement().stream()
+                .filter(Feature.class::isInstance)
+                .map(Feature.class::cast)
+                .findFirst()
+                .ifPresent(endFeature -> endFeature.getOwnedRelationship().add(owningMembership));
+    }
+
     @Test
     public void interfaceUsageWithUnresolvedPortEnd() {
         PartUsage rootPart = this.builder.createWithName(PartUsage.class, "part1");

backend/services/syson-sysml-metamodel-services/src/main/java/org/eclipse/syson/sysml/metamodel/services/textual/SysMLElementSerializer.java

@@ -1743,6 +1743,9 @@ private void appendConnectorEndMember(Appender builder, EndFeatureMembership end
     }
 
     private void appendConnectorEnd(Appender builder, Feature endFeature) {
+        // Prefix metadata of the end, such as the #original and #derive of a requirement derivation. Without this the
+        // metadata of an end owned through an EndFeatureMembership would be dropped by the export.
+        this.appendExtensionKeyword(builder, endFeature);
 
         // Handle ownedRelationship += OwnedMultiplicity
         endFeature.getOwnedRelationship().stream().filter(OwningMembership.class::isInstance)

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

@@ -92,6 +92,11 @@ Those connections were missing their source and their target, and were therefore
 ** Fix expression creation and editing on `SuccessionAsUsage` elements.
 ** Fix the _Typed by_ property in the _Details_ view so a `Usage` can only be typed by its corresponding `Definition` kind.
 
+* In textual import/export:
+
+** Fix the export of the keywords carried by the ends of a connection, such as the `#original` and `#derive` of a requirement derivation, which were missing from the exported text when the connection had been created from a diagram.
+Exporting such a connection and importing it back no longer loses which end is which.
+
 == Improvements
 
 * In diagrams: