public @NotNull RootDirtySet copy() {
    RootDirtySet copy = new RootDirtySet(myRoot, myCaseSensitive);
    if (myEverythingDirty) {
      copy.markEverythingDirty();
    }
    else {
      for (String filePath : myPaths) {
        copy.markDirtyRelative(filePath, 0);
      }
    }
    return copy;
  }
public @NotNull RootDirtySet copy()