Do not expose the system bundle from the host

See #2082

Author: laeubi

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/PDECore.java

@@ -47,6 +47,7 @@
 import org.eclipse.pde.core.project.IBundleProjectService;
 import org.eclipse.pde.core.target.ITargetDefinition;
 import org.eclipse.pde.core.target.ITargetPlatformService;
+import org.eclipse.pde.internal.build.IPDEBuildConstants;
 import org.eclipse.pde.internal.core.bnd.BndResourceChangeListener;
 import org.eclipse.pde.internal.core.bnd.BndWorkspaceServiceFactory;
 import org.eclipse.pde.internal.core.builders.FeatureRebuilder;
@@ -244,6 +245,11 @@ public PDECore() {
 	 *         {@link #VERSION} comparator.
 	 */
 	public Stream<IPluginModelBase> findPluginsInHost(String id) {
+		if (IPDEBuildConstants.BUNDLE_OSGI.equals(id)) {
+			// Do not expose the OSGi framework from the host see
+			// https://github.com/eclipse-pde/eclipse.pde/issues/2082
+			return Stream.empty();
+		}
 		Map<String, List<IPluginModelBase>> hostPlugins = getHostPlugins();
 		if (hostPlugins == null) {
 			return null;