TDF: bad interaction between multi-thread execution and separate output TFile

#include <ROOT/TDataFrame.hxx>

using namespace ROOT::Experimental;

void writeHistNoInputFile()

{

   std::cout << "write hist no input file" << std::endl;

   ROOT::EnableImplicitMT();

   TDataFrame d(10);

   auto counter = 0;

   auto dd = d.Define("x", [&counter]() { return counter++; });

   auto h = dd.Histo1D("x");

   TFile f("f1.root", "RECREATE");

   h->SetDirectory(&f);

   h->Write();

}

void makeDataSet()

{

   std::cout << "make dataset" << std::endl;

   TDataFrame d(10);

   auto counter = 0;

   auto dd = d.Define("x", [&counter]() { return counter++; });

   dd.Snapshot<int>("t", "f.root", {"x"});

}

void writeHistWithInputFile()

{

   std::cout << "write hist with input file" << std::endl;

   TDataFrame d("t", "f.root");

   auto h = d.Histo1D("x");

   TFile f("f2.root", "RECREATE");

   h->SetDirectory(&f);

   h->Write();

}

int main()

{

   writeHistNoInputFile();

   makeDataSet();

   writeHistWithInputFile();

   return 0;

}

write hist no input file

make dataset

write hist with input file

Error in <TROOT::WriteTObject>: The current directory (root) is not associated with a file. The object () has not been written.