Error if the preferences are not of expected type

bundles/org.eclipse.core.resources/src/org/eclipse/core/internal/resources/Workspace.java

@@ -24,6 +24,7 @@
 import java.lang.management.ManagementFactory;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.text.MessageFormat;
 import java.util.*;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicLong;
@@ -1861,7 +1862,7 @@ protected void initializeMoveDeleteHook() {
 	 * Add the project scope to the preference service's default look-up order so
 	 * people get it for free
 	 */
-	private void initializePreferenceLookupOrder() {
+	private void initializePreferenceLookupOrder() throws CoreException {
 		PreferencesService service = PreferencesService.getDefault();
 		String[] original = service.getDefaultDefaultLookupOrder();
 		List<String> newOrder = new ArrayList<>();
@@ -1873,6 +1874,10 @@ private void initializePreferenceLookupOrder() {
 		if (node instanceof ProjectPreferences) {
 			ProjectPreferences projectPreferences = (ProjectPreferences) node;
 			projectPreferences.setWorkspace(this);
+		} else {
+			throw new CoreException(Status.error(MessageFormat.format(
+					"Internal error while open workspace, the scope {0} should always result in a ProjectPreferences node", //$NON-NLS-1$
+					ProjectScope.SCOPE)));
 		}
 	}