private static List<String> processRawPrunedPaths(String prunedPaths) {
    List<FieldNode> fieldNodes = new ArrayList<>();
    for (String p : prunedPaths.split(",")) {
      fieldNodes = FieldNode.mergeFieldNodes(fieldNodes, FieldNode.fromPath(p));
    }
    List<String> prunedPathList = new ArrayList<>();
    for (FieldNode fn : fieldNodes) {
      prunedPathList.addAll(fn.toPaths());
    }
    return prunedPathList;
  }
Given a list of raw pruned paths separated by ',', return a list of merged pruned paths.
For instance, if the 'prunedPaths' is "s.a, s, s", this returns ["s"].
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/serde/ParquetHiveSerDe.java