diff --git a/platform/lang-impl/src/com/intellij/util/indexing/AdditionalIndexableFileSet.java b/platform/lang-impl/src/com/intellij/util/indexing/AdditionalIndexableFileSet.java
index d1afeda79323..8d0a5766ba16 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/AdditionalIndexableFileSet.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/AdditionalIndexableFileSet.java
@@ -19,8 +19,6 @@ import com.intellij.openapi.extensions.Extensions;
 import com.intellij.openapi.roots.ContentIterator;
 import com.intellij.openapi.vfs.VfsUtil;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.openapi.vfs.VirtualFileManager;
-import com.intellij.util.containers.ContainerUtil;
 import gnu.trove.THashSet;
 
 import java.util.Set;
@@ -37,9 +35,7 @@ public class AdditionalIndexableFileSet implements IndexableFileSet {
 
   public AdditionalIndexableFileSet(IndexedRootsProvider... extensions) {
     for (IndexedRootsProvider provider : extensions) {
-      for (String url : provider.getRootsToIndex()) {
-        ContainerUtil.addIfNotNull(VirtualFileManager.getInstance().findFileByUrl(url), myRoots);
-      }
+      myRoots.addAll(IndexableSetContributor.getRootsToIndex(provider));
     }
   }
 
diff --git a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndex.java b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndex.java
index aac358d4351c..50e59becfa26 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndex.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndex.java
@@ -1906,9 +1906,7 @@ public class FileBasedIndex implements ApplicationComponent {
       if (project.isDisposed()) {
         return;
       }
-      final Set<String> rootsToIndex = provider.getRootsToIndex();
-      for (String url : rootsToIndex) {
-        final VirtualFile root = VirtualFileManager.getInstance().findFileByUrl(url);
+      for (VirtualFile root : IndexableSetContributor.getRootsToIndex(provider)) {
         if (visitedRoots.add(root)) {
           iterateRecursively(root, processor, indicator);
         }
diff --git a/platform/lang-impl/src/com/intellij/util/indexing/IndexableSetContributor.java b/platform/lang-impl/src/com/intellij/util/indexing/IndexableSetContributor.java
new file mode 100644
index 000000000000..3cf4d907d819
--- /dev/null
+++ b/platform/lang-impl/src/com/intellij/util/indexing/IndexableSetContributor.java
@@ -0,0 +1,41 @@
+package com.intellij.util.indexing;
+
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.openapi.vfs.VirtualFileManager;
+import com.intellij.util.NotNullFunction;
+import com.intellij.util.containers.ContainerUtil;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * @author peter
+ */
+public abstract class IndexableSetContributor implements IndexedRootsProvider {
+  @Override
+  public final Set<String> getRootsToIndex() {
+    return ContainerUtil.map2Set(getAdditionalRootsToIndex(), new NotNullFunction<VirtualFile, String>() {
+      @NotNull
+      @Override
+      public String fun(VirtualFile virtualFile) {
+        return virtualFile.getUrl();
+      }
+    });
+  }
+
+  public static Set<VirtualFile> getRootsToIndex(IndexedRootsProvider provider) {
+    if (provider instanceof IndexableSetContributor) {
+      return ((IndexableSetContributor)provider).getAdditionalRootsToIndex();
+    }
+
+    final HashSet<VirtualFile> result = new HashSet<VirtualFile>();
+    for (String url : provider.getRootsToIndex()) {
+      ContainerUtil.addIfNotNull(VirtualFileManager.getInstance().findFileByUrl(url), result);
+    }
+    return result;
+  }
+
+
+  public abstract Set<VirtualFile> getAdditionalRootsToIndex();
+}
diff --git a/platform/lang-impl/src/com/intellij/util/indexing/IndexedRootsProvider.java b/platform/lang-impl/src/com/intellij/util/indexing/IndexedRootsProvider.java
index 5e683479b1a8..bca1b6d4aede 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/IndexedRootsProvider.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/IndexedRootsProvider.java
@@ -21,6 +21,7 @@ import com.intellij.openapi.extensions.ExtensionPointName;
 import java.util.Set;
 
 /**
+ * @deprecated extend {@link com.intellij.util.indexing.IndexableSetContributor} instead
  * @author Dmitry Avdeev
  */
 public interface IndexedRootsProvider {
@@ -28,6 +29,7 @@ public interface IndexedRootsProvider {
   ExtensionPointName<IndexedRootsProvider> EP_NAME = new ExtensionPointName<IndexedRootsProvider>("com.intellij.indexedRootsProvider");
 
   /**
+   * @deprecated
    * @return each string is VFS url {@link com.intellij.openapi.vfs.VirtualFile#getUrl()} of the root to index. Cannot depend on project.
    */
   Set<String> getRootsToIndex();
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
index f39fae603943..ae295622ec5d 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
@@ -126,23 +126,27 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Ap
   }
 
   @TestOnly
-  public void cleanupForNextTest() throws IOException {
+  public void cleanupForNextTest(Set<VirtualFile> survivors) throws IOException {
     ApplicationManager.getApplication().runWriteAction(new Runnable() {
       public void run() {
         FileDocumentManager.getInstance().saveAllDocuments();
-        refresh(false);
       }
     });
     ((PersistentFS)ManagingFS.getInstance()).clearIdCache();
-    
-    final VirtualFile[] roots = ManagingFS.getInstance().getRoots(this);
-    for (VirtualFile root : roots) {
-      if (root instanceof VirtualDirectoryImpl) {
+
+    for (VirtualFile root : ManagingFS.getInstance().getRoots(this)) {
+      if (root instanceof VirtualDirectoryImpl && !survivors.contains(root)) {
         final VirtualDirectoryImpl directory = (VirtualDirectoryImpl)root;
-        directory.cleanupCachedChildren();
+        directory.cleanupCachedChildren(survivors);
       }
     }
 
+    ApplicationManager.getApplication().runWriteAction(new Runnable() {
+      public void run() {
+        refresh(false);
+      }
+    });
+
     myRootsToWatch.clear();
 
     final File file = new File(FileUtil.getTempDirectory());
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualDirectoryImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualDirectoryImpl.java
index f04cd9ac6405..c09216c8e727 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualDirectoryImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualDirectoryImpl.java
@@ -360,8 +360,16 @@ public class VirtualDirectoryImpl extends VirtualFileSystemEntry {
   }
 
   @TestOnly
-  public synchronized void cleanupCachedChildren() {
-    myChildren = null;
+  public synchronized void cleanupCachedChildren(Set<VirtualFile> survivors) {
+    if (survivors.contains(this)) {
+      for (VirtualFile file : getCachedChildren()) {
+        if (file instanceof VirtualDirectoryImpl) {
+          ((VirtualDirectoryImpl)file).cleanupCachedChildren(survivors);
+        }
+      }
+    } else {
+      myChildren = null;
+    }
   }
 
   public InputStream getInputStream() throws IOException {
diff --git a/platform/testFramework/src/com/intellij/testFramework/PlatformTestCase.java b/platform/testFramework/src/com/intellij/testFramework/PlatformTestCase.java
index 6139fac76449..802273fc7c08 100644
--- a/platform/testFramework/src/com/intellij/testFramework/PlatformTestCase.java
+++ b/platform/testFramework/src/com/intellij/testFramework/PlatformTestCase.java
@@ -53,6 +53,7 @@ import com.intellij.openapi.vfs.VirtualFileManager;
 import com.intellij.openapi.vfs.impl.VirtualFilePointerManagerImpl;
 import com.intellij.openapi.vfs.impl.local.LocalFileSystemImpl;
 import com.intellij.openapi.vfs.newvfs.ManagingFS;
+import com.intellij.openapi.vfs.newvfs.impl.VirtualDirectoryImpl;
 import com.intellij.openapi.vfs.newvfs.persistent.PersistentFS;
 import com.intellij.openapi.vfs.pointers.VirtualFilePointerManager;
 import com.intellij.psi.PsiDocumentManager;
@@ -62,6 +63,8 @@ import com.intellij.psi.codeStyle.CodeStyleSettings;
 import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
 import com.intellij.psi.impl.PsiManagerEx;
 import com.intellij.util.PatchedWeakReference;
+import com.intellij.util.indexing.IndexableSetContributor;
+import com.intellij.util.indexing.IndexedRootsProvider;
 import junit.framework.TestCase;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.Nullable;
@@ -73,6 +76,7 @@ import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.util.Collection;
 import java.util.HashSet;
+import java.util.Set;
 
 /**
  * @author yole
@@ -96,6 +100,7 @@ public abstract class PlatformTestCase extends UsefulTestCase implements DataPro
   private ThreadTracker myThreadTracker;
 
   protected static boolean ourPlatformPrefixInitialized;
+  private static Set<VirtualFile> ourEternallyLivingFiles;
 
   static {
     Logger.setFactory(TestLoggerFactory.getInstance());
@@ -267,7 +272,7 @@ public abstract class PlatformTestCase extends UsefulTestCase implements DataPro
     try {
       LocalFileSystemImpl localFileSystem = (LocalFileSystemImpl)LocalFileSystem.getInstance();
       if (localFileSystem != null) {
-        localFileSystem.cleanupForNextTest();
+        localFileSystem.cleanupForNextTest(eternallyLivingFiles());
       }
     }
     catch (IOException e) {
@@ -283,6 +288,35 @@ public abstract class PlatformTestCase extends UsefulTestCase implements DataPro
     PatchedWeakReference.clearAll();
   }
 
+  private static void addSubTree(VirtualFile root, Set<VirtualFile> to) {
+    if (root instanceof VirtualDirectoryImpl) {
+      for (VirtualFile child : ((VirtualDirectoryImpl)root).getCachedChildren()) {
+        to.add(child);
+        addSubTree(child, to);
+      }
+    }
+  }
+
+  private static Set<VirtualFile> eternallyLivingFiles() {
+    if (ourEternallyLivingFiles != null) {
+      return ourEternallyLivingFiles;
+    }
+
+    Set<VirtualFile> survivors = new HashSet<VirtualFile>();
+
+    for (IndexedRootsProvider provider : IndexedRootsProvider.EP_NAME.getExtensions()) {
+      for (VirtualFile file : IndexableSetContributor.getRootsToIndex(provider)) {
+        addSubTree(file, survivors);
+        while (file != null && survivors.add(file)) {
+          file = file.getParent();
+        }
+      }
+    }
+
+    ourEternallyLivingFiles = survivors;
+    return survivors;
+  }
+
   protected void tearDown() throws Exception {
     LightPlatformTestCase.doTearDown(getProject(), ourApplication, false);
 
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/AbstractDslIndexedRootsProvider.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/AbstractDslIndexedRootsProvider.java
index e8c01b69eac4..de632f999bdb 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/AbstractDslIndexedRootsProvider.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/AbstractDslIndexedRootsProvider.java
@@ -18,13 +18,14 @@ package org.jetbrains.plugins.groovy.dsl;
 import com.intellij.openapi.vfs.LocalFileSystem;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.PathUtil;
+import com.intellij.util.indexing.IndexableSetContributor;
 
 import java.io.File;
 import java.util.Collections;
 import java.util.Set;
 
-public class AbstractDslIndexedRootsProvider implements GroovyDslIndexedRootProvider {
-  private final Set<String> ourDslsDirs;
+public class AbstractDslIndexedRootsProvider extends IndexableSetContributor implements GroovyDslIndexedRootProvider{
+  private final Set<VirtualFile> ourDslsDirs;
 
   public AbstractDslIndexedRootsProvider() {
     final File jarPath = new File(PathUtil.getJarPathForClass(getClass()));
@@ -38,7 +39,7 @@ public class AbstractDslIndexedRootsProvider implements GroovyDslIndexedRootProv
     final VirtualFile parent = LocalFileSystem.getInstance().refreshAndFindFileByPath(dirPath);
     assert parent != null : dirPath;
     parent.getChildren();
-    ourDslsDirs = Collections.singleton(parent.getUrl());
+    ourDslsDirs = Collections.singleton(parent);
     parent.refresh(true, true);
   }
 
@@ -46,7 +47,8 @@ public class AbstractDslIndexedRootsProvider implements GroovyDslIndexedRootProv
     return "standardDsls";
   }
 
-  public Set<String> getRootsToIndex() {
+  @Override
+  public Set<VirtualFile> getAdditionalRootsToIndex() {
     return ourDslsDirs;
   }
 }
diff --git a/xml/impl/src/com/intellij/xml/index/ExternalResourcesRootsProvider.java b/xml/impl/src/com/intellij/xml/index/ExternalResourcesRootsProvider.java
index d30732b5eb60..3506b1a0cddf 100644
--- a/xml/impl/src/com/intellij/xml/index/ExternalResourcesRootsProvider.java
+++ b/xml/impl/src/com/intellij/xml/index/ExternalResourcesRootsProvider.java
@@ -21,7 +21,7 @@ import com.intellij.openapi.vfs.LocalFileSystem;
 import com.intellij.openapi.vfs.VfsUtil;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.containers.hash.HashSet;
-import com.intellij.util.indexing.IndexedRootsProvider;
+import com.intellij.util.indexing.IndexableSetContributor;
 import org.jetbrains.annotations.Nullable;
 
 import java.net.URL;
@@ -30,7 +30,7 @@ import java.util.Set;
 /**
  * @author Dmitry Avdeev
  */
-public class ExternalResourcesRootsProvider implements IndexedRootsProvider {
+public class ExternalResourcesRootsProvider extends IndexableSetContributor {
   private static final URL ourRoot = ExternalResourcesRootsProvider.class.getResource(ExternalResourceManagerImpl.STANDARD_SCHEMAS);
 
   @Nullable
@@ -38,17 +38,17 @@ public class ExternalResourcesRootsProvider implements IndexedRootsProvider {
     return ourRoot == null ? null : VfsUtil.findFileByURL(ourRoot);
   }
 
-  public Set<String> getRootsToIndex() {
+  public Set<VirtualFile> getAdditionalRootsToIndex() {
     final VirtualFile standardSchemas = getStandardSchemas();
     String path = FetchExtResourceAction.getExternalResourcesPath();
     LocalFileSystem localFileSystem = LocalFileSystem.getInstance();
     VirtualFile extResources = localFileSystem.findFileByPath(path);
-    HashSet<String> roots = new HashSet<String>(2);
+    HashSet<VirtualFile> roots = new HashSet<VirtualFile>(2);
     if (standardSchemas != null) {
-      roots.add(standardSchemas.getUrl());
+      roots.add(standardSchemas);
     }
     if (extResources != null) {
-      roots.add(extResources.getUrl());
+      roots.add(extResources);
     }
     return roots;
   }