fix NPE on adding a library with invalid roots

java/idea-ui/src/com/intellij/openapi/roots/ui/configuration/libraryEditor/NewLibraryEditor.java

@@ -81,6 +81,10 @@ public class NewLibraryEditor implements LibraryEditor {
     List<VirtualFile> result = new ArrayList<VirtualFile>();
     for (LightFilePointer pointer : myRoots.get(rootType)) {
       final VirtualFile file = pointer.getFile();
+      if (file == null) {
+        continue;
+      }
+
       if (file.isDirectory()) {
         final Boolean recursively = myJarDirectories.get(file.getUrl());
         if (recursively != null) {

platform/platform-api/src/com/intellij/openapi/roots/ui/LightFilePointer.java

@@ -19,6 +19,7 @@ import com.intellij.openapi.vfs.JarFileSystem;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.openapi.vfs.VirtualFileManager;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 
@@ -35,6 +36,7 @@ public class LightFilePointer  {
     myFile = file;
   }
 
+  @Nullable
   public VirtualFile getFile() {
     refreshFile();
     return myFile;