Description
Check duplicate issues.
- Checked for duplicates
Description
Hello,
I am creating this issue because there is a bug when setting an entry list that has already been used to a TTree.
The entry number returned by tree->GetEntryNumber(index) are messed up until that function is called 2 times in a row for the same index.
You can find a standalone simple reproducer of the bug below.
In that code by setting numTest to 0, 1 or 2 you will obtain the different print below.
With that example by calling tree->GetEntryNumber(index) it should return the value index
e.g. tree->GetEntryNumber(2) should return 2. However until the GetEntryNumber() function has not been called 2 times for the same index then the returned entry number is NOT the expected one.
Here it is simple to solve the issue i.e. not call entryList->GetEntry(15); before setting the entry list to the tree
but I find this behaviour really error prone as one would need to be sure the entry list has never been used basically.
On the other hand using the copy constructor allows not having this issue because I think the fLastIndexQueried is reset to -1
tree->SetEntryList( new TEntryList(*entryList) );
Tagging @pcanal and @Axel-Naumann
For numTest=0
tree->GetEntryNumber(0)=16
tree->GetEntryNumber(0)=0
tree->GetEntryNumber(0)=0
tree->GetEntryNumber(0)=0
For numTest=1
tree->GetEntryNumber(0)=16
tree->GetEntryNumber(1)=17
tree->GetEntryNumber(1)=1
tree->GetEntryNumber(1)=1
For numTest=2
tree->GetEntryNumber(0)=16
tree->GetEntryNumber(1)=17
tree->GetEntryNumber(2)=18
tree->GetEntryNumber(2)=2
tree->GetEntryNumber(2)=2
Reproducer
#include "TFile.h"
#include "TTree.h"
#include "TError.h"
#include "TEntryList.h"
#include<string>
#include<vector>
#include<iostream>
// function defined after main
void createTree(const std::string &outputFile);
int main(){
// number of the test
// set to 0, 1 or 2
int numTest = 2;
// Define an entry list
TEntryList *entryList = new TEntryList();
std::vector<long long int> entries={
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19
};
// fill the entry list
for (long long int entry : entries){
entryList->Enter(entry);
}
// Create tree
std::string inFileName = "myFile.root";
createTree(inFileName);
// Read tree
TFile *file = nullptr;
TTree *tree = nullptr;
file = TFile::Open(inFileName.c_str());
tree = (TTree*) file->Get("myTree");
// On purpose get entry 15
// before setting entry list for tree
entryList->GetEntry(15);
tree->SetEntryList(entryList);
if (numTest == 0){
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
}
if (numTest == 1){
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
std::cout << "tree->GetEntryNumber(1)=" << tree->GetEntryNumber(1) << std::endl;
std::cout << "tree->GetEntryNumber(1)=" << tree->GetEntryNumber(1) << std::endl;
std::cout << "tree->GetEntryNumber(1)=" << tree->GetEntryNumber(1) << std::endl;
}
if (numTest == 2){
std::cout << "tree->GetEntryNumber(0)=" << tree->GetEntryNumber(0) << std::endl;
std::cout << "tree->GetEntryNumber(1)=" << tree->GetEntryNumber(1) << std::endl;
std::cout << "tree->GetEntryNumber(2)=" << tree->GetEntryNumber(2) << std::endl;
std::cout << "tree->GetEntryNumber(2)=" << tree->GetEntryNumber(2) << std::endl;
std::cout << "tree->GetEntryNumber(2)=" << tree->GetEntryNumber(2) << std::endl;
}
return 0;
}
void createTree(const std::string &outputFile){
unsigned int NEntries = 100;
TTree *tree = nullptr;
double x1;
// create file
TFile *file = TFile::Open(outputFile.c_str(),"recreate");
// init tree
tree = new TTree("myTree","myTree");
tree->Branch("x1", &x1);
for (unsigned int iEntry = 0 ; iEntry < NEntries; iEntry++){
x1 = iEntry;
tree->Fill();
}
file->Write();
delete file;
}ROOT version
ROOT Version: 6.26/08
I believe all versions are affected by that bug even the most recent ones
Installation method
Built from source
Operating system
Linux
Additional context
No response