Program: 80121
Project: 80121
Buggy source:
@Override public long deleteByQuery(Query<K,T> query){
  Delete delete=new Delete();
  delete.from(orientDBMapping.getDocumentClass());
  Map<String,Object> params=new HashMap<String,Object>();
  if (query.getFields() == null || (query.getFields().length == getFields().length)) {
    if (query.getStartKey() != null) {
      delete.where(projection("String_Node_Str").ge(Parameter.parameter("String_Node_Str")));
      params.put("String_Node_Str",query.getStartKey());
    }
    if (query.getEndKey() != null) {
      delete.where(projection("String_Node_Str").le(Parameter.parameter("String_Node_Str")));
      params.put("String_Node_Str",query.getEndKey());
    }
    OCommandSQL dbQuery=new OCommandSQL(delete.toString().replace("String_Node_Str","String_Node_Str"));
    ODatabaseDocumentTx deleteTx=connectionPool.acquire();
    deleteTx.activateOnCurrentThread();
    try {
      int deleteCount;
      if (params.isEmpty()) {
        deleteCount=deleteTx.command(dbQuery).execute();
      }
 else {
        deleteCount=deleteTx.command(dbQuery).execute(params);
      }
      if (deleteCount > 0) {
        return deleteCount;
      }
 else {
        return 0;
      }
    }
  finally {
      deleteTx.close();
    }
  }
 else {
    OrientDBQuery<K,T> dataStoreQuery=new OrientDBQuery<>(this);
    dataStoreQuery.setStartKey(query.getStartKey());
    dataStoreQuery.setEndKey(query.getEndKey());
    dataStoreQuery.populateOrientDBQuery(orientDBMapping,getFieldsToQuery(null),getFields());
    ODatabaseDocumentTx selectTx=connectionPool.acquire();
    selectTx.activateOnCurrentThread();
    try {
      List<ODocument> result=selectTx.command(dataStoreQuery.getOrientDBQuery()).execute(dataStoreQuery.getParams());
      if (result != null && result.isEmpty()) {
        return 0;
      }
 else {
        for (        ODocument doc : result) {
          for (          String docField : query.getFields()) {
            if (doc.containsField(orientDBMapping.getDocumentField(docField))) {
              doc.removeField(orientDBMapping.getDocumentField(docField));
            }
          }
          doc.save();
        }
        return result.size();
      }
    }
  finally {
      selectTx.close();
    }
  }
}

Fixed version (ground truth):
/** 
 * {@inheritDoc}
 */
@Override public long deleteByQuery(Query<K,T> query){
  Delete delete=new Delete();
  delete.from(orientDBMapping.getDocumentClass());
  Map<String,Object> params=new HashMap<String,Object>();
  if (query.getFields() == null || (query.getFields().length == getFields().length)) {
    if (query.getStartKey() != null) {
      delete.where(projection("String_Node_Str").ge(Parameter.parameter("String_Node_Str")));
      params.put("String_Node_Str",query.getStartKey());
    }
    if (query.getEndKey() != null) {
      delete.where(projection("String_Node_Str").le(Parameter.parameter("String_Node_Str")));
      params.put("String_Node_Str",query.getEndKey());
    }
    OCommandSQL dbQuery=new OCommandSQL(delete.toString().replace("String_Node_Str","String_Node_Str"));
    ODatabaseDocumentTx deleteTx=connectionPool.acquire();
    deleteTx.activateOnCurrentThread();
    try {
      int deleteCount;
      if (params.isEmpty()) {
        deleteCount=deleteTx.command(dbQuery).execute();
      }
 else {
        deleteCount=deleteTx.command(dbQuery).execute(params);
      }
      if (deleteCount > 0) {
        return deleteCount;
      }
 else {
        return 0;
      }
    }
  finally {
      deleteTx.close();
    }
  }
 else {
    OrientDBQuery<K,T> dataStoreQuery=new OrientDBQuery<>(this);
    dataStoreQuery.setStartKey(query.getStartKey());
    dataStoreQuery.setEndKey(query.getEndKey());
    dataStoreQuery.populateOrientDBQuery(orientDBMapping,getFieldsToQuery(null),getFields());
    ODatabaseDocumentTx selectTx=connectionPool.acquire();
    selectTx.activateOnCurrentThread();
    try {
      List<ODocument> result=selectTx.command(dataStoreQuery.getOrientDBQuery()).execute(dataStoreQuery.getParams());
      if (result != null && result.isEmpty()) {
        return 0;
      }
 else {
        for (        ODocument doc : result) {
          for (          String docField : query.getFields()) {
            if (doc.containsField(orientDBMapping.getDocumentField(docField))) {
              doc.removeField(orientDBMapping.getDocumentField(docField));
            }
          }
          doc.save();
        }
        return result.size();
      }
    }
  finally {
      selectTx.close();
    }
  }
}