Fix E4 model perspectives being converted to orphan local copies

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/WorkbenchPage.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2020 IBM Corporation and others.
+ * Copyright (c) 2000, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -3908,8 +3908,19 @@ private Perspective getPerspective(MPerspective mperspective) {
 			PerspectiveDescriptor perspectiveDesc = (PerspectiveDescriptor) getPerspectiveDesc(
 					mperspective.getElementId());
 			if (perspectiveDesc == null) {
-				fixedPerspective = true;
-				perspectiveDesc = fixOrphanPerspective(mperspective);
+				if (mperspective.getContributorURI() != null) {
+					PerspectiveRegistry reg = (PerspectiveRegistry) PlatformUI.getWorkbench().getPerspectiveRegistry();
+					// Registers an E4 perspective that is contributed directly via the application
+					// model (e.g. via a model fragment), without renaming it or marking it as a
+					// local copy. Unlike PerspectiveRegistry#addPerspective(MPerspective),
+					// this method does not add the perspective to the application snippets.
+					reg.createDescriptor(mperspective);
+					perspectiveDesc = (PerspectiveDescriptor) getPerspectiveDesc(mperspective.getElementId());
+					sortedPerspectives.add(perspectiveDesc);
+				} else {
+					fixedPerspective = true;
+					perspectiveDesc = fixOrphanPerspective(mperspective);
+				}
 			}
 			Perspective p = new Perspective(perspectiveDesc, mperspective, this);
 			modelToPerspectiveMapping.put(mperspective, p);

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/registry/PerspectiveRegistry.java

@@ -114,7 +114,7 @@ public void addPerspective(MPerspective perspective) {
 		createDescriptor(perspective);
 	}
 
-	private void createDescriptor(MPerspective perspective) {
+	public void createDescriptor(MPerspective perspective) {
 		String label = perspective.getLocalizedLabel();
 		String originalId = getOriginalId(perspective);
 		PerspectiveDescriptor originalDescriptor = descriptors.get(originalId);
@@ -319,7 +319,7 @@ private String getOriginalId(MPerspective p) {
 					p.getContributorURI()));
 		}
 		int index = id.lastIndexOf('.');
-		// Custom perspectives store the user defined names in their labels
+		// Custom perspectives store the user defined names in their labels.
 		String trimE4 = label.trim();
 		String trimE3 = label.replace(' ', '_').trim();
 		if (id.endsWith(label)) {

tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/api/IWorkbenchPageTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2019 IBM Corporation and others.
+ * Copyright (c) 2000, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -48,7 +48,10 @@
 import org.eclipse.core.runtime.ILogListener;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
+import org.eclipse.e4.ui.model.application.ui.advanced.MPerspective;
+import org.eclipse.e4.ui.model.application.ui.advanced.MPerspectiveStack;
 import org.eclipse.e4.ui.model.application.ui.basic.MPart;
+import org.eclipse.e4.ui.workbench.modeling.EModelService;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.swt.events.ShellEvent;
@@ -80,7 +83,9 @@
 import org.eclipse.ui.ide.IDE;
 import org.eclipse.ui.internal.WorkbenchPage;
 import org.eclipse.ui.internal.WorkbenchPlugin;
+import org.eclipse.ui.internal.WorkbenchWindow;
 import org.eclipse.ui.internal.registry.IActionSetDescriptor;
+import org.eclipse.ui.internal.registry.PerspectiveDescriptor;
 import org.eclipse.ui.internal.util.Util;
 import org.eclipse.ui.navigator.resources.ProjectExplorer;
 import org.eclipse.ui.part.FileEditorInput;
@@ -3349,6 +3354,43 @@ public void testGetViewStackWithSecondaryId() throws PartInitException {
 		assertEquals(part, stack[0]);
 	}
 
+	@Test
+	public void testE4PerspectiveNotConvertedToLocalCopy() {
+		IWorkbenchWindow window = openTestWindow();
+		EModelService modelService = window.getService(EModelService.class);
+
+		WorkbenchWindow workbenchWindow = (WorkbenchWindow) window;
+		List<MPerspectiveStack> stacks = modelService.findElements(workbenchWindow.getModel(), null,
+				MPerspectiveStack.class);
+		assertFalse("Perspective stack should exist in the window model", stacks.isEmpty());
+		MPerspectiveStack perspectiveStack = stacks.get(0);
+
+		String e4Id = "org.eclipse.ui.tests.internal.e4.perspective.model";
+		String e4Label = "E4ModelPerspective";
+
+		assertNull("e4 perspective ID should not be in perspective registry",
+				PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(e4Id));
+
+		MPerspective e4Perspective = modelService.createModelElement(MPerspective.class);
+		e4Perspective.setElementId(e4Id);
+		e4Perspective.setLabel(e4Label);
+		e4Perspective.setContributorURI("platform:/plugin/org.eclipse.ui.tests");
+
+		perspectiveStack.getChildren().add(e4Perspective);
+		perspectiveStack.setSelectedElement(e4Perspective);
+		processEvents();
+
+		assertEquals("Element ID should not have changed", e4Id, e4Perspective.getElementId());
+
+		IPerspectiveDescriptor descriptor = PlatformUI.getWorkbench().getPerspectiveRegistry()
+				.findPerspectiveWithId(e4Id);
+		assertNotNull(descriptor);
+
+		assertFalse(((PerspectiveDescriptor) descriptor).hasCustomDefinition());
+
+		PlatformUI.getWorkbench().getPerspectiveRegistry().deletePerspective(descriptor);
+	}
+
 	private static class ShellStateListener implements ShellListener {
 		private final AtomicBoolean shellIsActive;
 

tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/internal/InternalTestSuite.java

@@ -30,7 +30,6 @@
 import org.eclipse.ui.tests.markers.MarkerViewUtilTest;
 import org.eclipse.ui.tests.markers.ResourceMappingMarkersTest;
 import org.eclipse.ui.tests.markers.ScopeAreaTest;
-
 import org.junit.platform.suite.api.SelectClasses;
 import org.junit.platform.suite.api.Suite;