ContainerUtil.notNullize for Set

platform/platform-api/src/com/intellij/ui/CollectionListModel.java

@@ -103,6 +103,7 @@ public class CollectionListModel<T> extends AbstractListModel implements Editabl
     Collections.sort(myItems, comparator);
   }
 
+  @NotNull
   public List<T> getItems() {
     return Collections.unmodifiableList(myItems);
   }

platform/util/src/com/intellij/util/containers/ContainerUtil.java

@@ -2274,9 +2274,15 @@ public class ContainerUtil extends ContainerUtilRt {
 
   @NotNull
   @Contract(pure=true)
-  public static <T, C extends Collection<T>> C notNullize(@Nullable C collection) {
+  public static <T> List<T> notNullize(@Nullable List<T> list) {
+    return list == null ? ContainerUtilRt.<T>emptyList() : list;
+  }
+
+  @NotNull
+  @Contract(pure=true)
+  public static <T> Set<T> notNullize(@Nullable Set<T> set) {
     //noinspection unchecked
-    return collection == null ? (C)ContainerUtilRt.emptyList() : collection;
+    return set == null ? Collections.<T>emptySet() : set;
   }
 
   @Nullable

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/VcsStructureChooser.java

@@ -126,6 +126,7 @@ public class VcsStructureChooser extends DialogWrapper {
     return myModulesSet;
   }
 
+  @NotNull
   public Collection<VirtualFile> getSelectedFiles() {
     return ((CollectionListModel) mySelectedList.getModel()).getItems();
   }

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/filter/StructureFilterPopupComponent.java

@@ -101,7 +101,7 @@ class StructureFilterPopupComponent extends FilterPopupComponent<VcsLogStructure
                                                             new ArrayList<VirtualFile>(myRoots));
       if (chooser.showAndGet()) {
         myFiles.clear();
-        myFiles.addAll(ContainerUtil.notNullize(chooser.getSelectedFiles()));
+        myFiles.addAll(chooser.getSelectedFiles());
         setValue(myFiles);
         applyFilters();
       }