[1077] Fix explorer in case of non-sysml domain

Fix behavior of hasChildren management of syson explorer when handling model elements from non-sysml domains. It now falls back to SiriusWeb implementation when necessary.

Signed-off-by: Didier Vojtisek <[email protected]>

CHANGELOG.adoc

@@ -15,6 +15,8 @@
 
 === Bug fixes
 
+- https://github.com/eclipse-syson/syson/issues/1077[#1077] [explorer] Fix navigation in case of project containing both sysml and non-sysml model elements
+
 === Improvements
 
 - https://github.com/eclipse-syson/syson/issues/1061[#1061] [general-view] Add ellipsis on `Packages` label, to provide visual feedback on name overflow.
@@ -63,6 +65,7 @@ Export to textual SysMLv2 is not fully implemented yet so there are still unhand
 - https://github.com/eclipse-syson/syson/issues/1020[#1020] [general-view] The multiplicity should not be displayed on edges.
 - https://github.com/eclipse-syson/syson/issues/1009[#1009] [metamodel] Fix an issue where the diagram direct edit on graphical nodes could raise a backend error on unsettable enum attributes.
 - https://github.com/eclipse-syson/syson/issues/1052[#1052] [general-view] Fix an issue where the execution of "New Port In/Inout/Out" tools was failing.
+- https://github.com/eclipse-syson/syson/issues/1077[#1077] [explorer] Fix navigation in case of project containing both sysml and non-sysml model elements
 
 === Improvements
 

backend/views/syson-tree-explorer-view/src/main/java/org/eclipse/syson/tree/explorer/view/services/SysONDefaultExplorerServices.java

@@ -24,6 +24,7 @@
 import org.eclipse.sirius.components.core.api.IIdentityService;
 import org.eclipse.sirius.web.application.UUIDParser;
 import org.eclipse.sirius.web.application.editingcontext.EditingContext;
+import org.eclipse.sirius.web.application.views.explorer.services.ExplorerServices;
 import org.eclipse.sirius.web.application.views.explorer.services.api.IExplorerServices;
 import org.eclipse.sirius.web.domain.boundedcontexts.representationdata.services.api.IRepresentationMetadataSearchService;
 import org.eclipse.syson.services.UtilService;
@@ -57,13 +58,16 @@ public class SysONDefaultExplorerServices implements ISysONDefaultExplorerServic
 
     private final UtilService utilService = new UtilService();
 
+    private final ExplorerServices siriuswebExplorerService;
+
     public SysONDefaultExplorerServices(IIdentityService identityService, IContentService contentService, IRepresentationMetadataSearchService representationMetadataSearchService, IExplorerServices explorerServices,
-            ISysONExplorerFilterService filterService) {
+            ISysONExplorerFilterService filterService, ExplorerServices siriuswebExplorerService) {
         this.identityService = Objects.requireNonNull(identityService);
         this.contentService = Objects.requireNonNull(contentService);
         this.representationMetadataSearchService = Objects.requireNonNull(representationMetadataSearchService);
         this.explorerServices = Objects.requireNonNull(explorerServices);
         this.filterService = Objects.requireNonNull(filterService);
+        this.siriuswebExplorerService = Objects.requireNonNull(siriuswebExplorerService);
     }
 
     @Override
@@ -133,6 +137,8 @@ public boolean hasChildren(Object self, IEditingContext editingContext, List<Str
             List<Object> contents = this.filterService.applyFilters(this.contentService.getContents(self), activeFilterIds);
             hasChildren = !contents.isEmpty() && contents.stream().anyMatch(e -> !(e instanceof EAnnotation))
                 || this.hasRepresentation(element, editingContext);
+        } else {
+            siriuswebExplorerService.hasChildren(self, editingContext);
         }
         return hasChildren;
     }

doc/content/modules/user-manual/pages/release-notes/2025.4.0.adoc

@@ -4,6 +4,8 @@
 
 == Bug fixes
 
+- In `Explorer View`, the fold/unfold arrow is now also available for non-sysml model elements.
+
 == New features
 
 == Improvements