Add support for nested problems display for hierarchical projects

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java

@@ -24,11 +24,14 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Set;
 
 import org.eclipse.core.commands.operations.IUndoContext;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IMarker;
+import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.Adapters;
 import org.eclipse.core.runtime.Assert;
@@ -1642,16 +1645,35 @@ public void selectionChanged(IWorkbenchPart part, ISelection selection) {
 			}
 			// try to adapt them in resources and add it to the
 			// selectedElements
-			List<Object> selectedElements = new ArrayList<>();
+			Set<Object> selectedElements = new LinkedHashSet<>();
 			for (Object object : objectsToAdapt) {
 				Object resElement = MarkerResourceUtil.adapt2ResourceElement(object);
 				if (resElement != null) {
 					selectedElements.add(resElement);
 				}
 			}
+			if (isProjectNestingActive(part)) {
+				List<IProject> selectedProjects = selectedElements.stream().filter(IProject.class::isInstance)
+						.map(IProject.class::cast).toList();
+				if (!selectedProjects.isEmpty()) {
+					selectedElements.addAll(MarkerResourceUtil.getNestedChildProjects(selectedProjects));
+				}
+			}
 			MarkerContentGenerator gen = view.getGenerator();
 			gen.updateSelectedResource(selectedElements.toArray(), part == null);
 		}
+
+	}
+
+	/**
+	 * Check if project nesting is active for this marker view
+	 *
+	 * @param part the currently selected part
+	 * @return <code>true</code> if nesting should be performed, <code>false</code>
+	 *         otherwise
+	 */
+	protected boolean isProjectNestingActive(IWorkbenchPart part) {
+		return false;
 	}
 
 	/**

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerResourceUtil.java

@@ -31,6 +31,7 @@
 import org.eclipse.core.runtime.Adapters;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IAdaptable;
+import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.ui.internal.ide.Policy;
 import org.eclipse.ui.internal.util.Util;
@@ -286,6 +287,45 @@ static Collection<IProject> getProjectsAsCollection(Object[] elements) {
 		return projects;
 	}
 
+	/**
+	 * Returns all nested child projects of the given projects. A project is
+	 * considered a nested child if its location is a descendant of the parent
+	 * project's location. This supports the hierarchical project display feature.
+	 *
+	 * @param parentProjects
+	 *            the projects to find nested children for
+	 * @return collection of all nested child projects (does not include the parent
+	 *         projects themselves)
+	 */
+	static Collection<IProject> getNestedChildProjects(Collection<IProject> parentProjects) {
+		if (parentProjects == null || parentProjects.isEmpty()) {
+			return Set.of();
+		}
+		Set<IProject> nestedChildren = new HashSet<>();
+
+		for (IProject project : ResourcesPlugin.getWorkspace().getRoot().getProjects()) {
+			if (!project.exists() || !project.isAccessible()) {
+				continue;
+			}
+			IPath projectLocation = project.getLocation();
+			if (projectLocation == null) {
+				continue;
+			}
+			// Check if this project is nested under any of the parent projects
+			for (IProject parentProject : parentProjects) {
+				if (parentProject.equals(project)) {
+					continue; // Skip the project itself
+				}
+				IPath parentLocation = parentProject.getLocation();
+				if (parentLocation != null && parentLocation.isPrefixOf(projectLocation)) {
+					nestedChildren.add(project);
+					break;
+				}
+			}
+		}
+		return nestedChildren;
+	}
+
 	/**
 	 * Add the resources in resourceMapping to the resourceCollection
 	 */

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ProblemsView.java

@@ -17,9 +17,11 @@
 import org.eclipse.core.resources.IMarker;
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.swt.graphics.Image;
+import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.ide.undo.WorkspaceUndoUtil;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.ide.IDEInternalWorkbenchImages;
+import org.eclipse.ui.navigator.CommonNavigator;
 import org.eclipse.ui.views.markers.MarkerSupportView;
 import org.eclipse.ui.views.markers.internal.MarkerMessages;
 import org.eclipse.ui.views.markers.internal.MarkerSupportRegistry;
@@ -64,4 +66,14 @@ protected String getDeleteOperationName(IMarker[] markers) {
 		return markers.length == 1 ? MarkerMessages.deleteProblemMarker_operationName : MarkerMessages.deleteProblemMarkers_operationName;
 	}
 
+	@Override
+	protected boolean isProjectNestingActive(IWorkbenchPart part) {
+		if (part instanceof CommonNavigator navigator) {
+			return navigator.getNavigatorContentService().getActivationService().isNavigatorExtensionActive(
+					"org.eclipse.ui.navigator.resources.nested.nestedProjectContentProvider"); //$NON-NLS-1$
+
+		}
+		return false;
+	}
+
 }