[ROOT-10152] [DF] Cannot analyze friend trees in subdirectories with MT - SFTJIRA

XML

Word

Printable

As reported in the forum (https://root-forum.cern.ch/t/rdf-friend-tree-in-subdirectory-of-file-mt-not-working/34219) processing a tree with a friend tree in a subdirectory of a root file with the RDataFrame does not work with Implicit MT enabled (without everything is fine).

This is a reproducer which results in a seg fault when the event loop is triggered:

#include <TROOT.h>

#include <ROOT/RDataFrame.hxx>

#include <ROOT/RVec.hxx>

#include <TNtuple.h>

#include <TFile.h>

void create_file()

   // Setting up trees

   auto f = TFile::Open("myfile.root", "RECREATE");

   TNtuple* t = new TNtuple("main", "", "val");

   TNtuple* tf = new TNtuple("friend", "", "val2");

   const auto vals = {1, 2, 3, 4, 5};

   for (const auto& val : vals)

      t->Fill(val);

      tf->Fill(-val);

   auto dir = f->mkdir("main");

   dir->cd();

   t->Write();

   f->cd();

   auto dir2 = f->mkdir("friend");

   dir2->cd();

   tf->Write();

   f->Close();

void analyze()

   // Read file

   auto f = TFile::Open("myfile.root", "READ");

   TTree* t = (TTree*) f->Get("main/main");

   TTree* tf = (TTree*) f->Get("friend/friend");   // Add friend

   t->AddFriend(tf, "friend");

   auto df = ROOT::RDataFrame(*t);   // Trigger event loop

   std::cout << *df.Count() << std::endl;

int main()

   ROOT::EnableImplicitMT();

   create_file();

   analyze();