Add a try / catch block around truth lepton retrieval
This touches a few dumpers but should only make a difference in very rare events.
Apparently some things are missing in the truth record sometimes. This should
be very rare (first time I saw it it happened after around 80k events). Since this is a problem upstream we have to ignore it now, but just
to keep track, I'm counting this and printing it to userJobMetadata.json
.
After I wrote this MR I realized I'd done exactly the same thing on dump-single-btag.cxx
so I decided to consolidate the definitions a bit.