Fix bug with merging where TChain::Merge implicitly took ownership of TFile and auto close and deleted

This commit is contained in:
Gordon McCann 2023-01-16 11:32:00 -05:00
parent 4886c497a3
commit a264eea63c

View File

@ -191,7 +191,7 @@ namespace EventBuilder {
return false;
TFile* output = TFile::Open(outputname.c_str(), "RECREATE");
if(!output->IsOpen())
if(!output || !output->IsOpen())
{
EVB_ERROR("Could not open output file {0} for merge", outputname);
output->Close();
@ -200,8 +200,15 @@ namespace EventBuilder {
TChain* chain = new TChain("SPSTree", "SPSTree");
for(auto& entry : files)
{
EVB_INFO("Merging file: {0}", entry);
chain->Add(entry.c_str());
chain->Merge(output, 0, "fast");
}
//Note: TChain merge is kinda fucked. It requires a file passed in, which it then implicitly takes ownership of.
//By passing the keep option, we tell TChain we want to keep ownership of the file (otherwise it will automatically close and delete)
//We need ownership because the Merge function does not do a good job of handling errors explicitly.
chain->Merge(output, 0, "fast|keep");
output->Close();
return true;
}