TRD digit QC protection against division by zero

[martenole]

Fix for FPE observed in alibi nightly MC tests.
Ping @knopers8

[chiarazampolli]

Hello @martenole , @knopers8 ,

We will need a new tag from QC for PbPb with this fix. Can this be done? We would need it as soon as possible - as always :-)

Cheers,
Chiara

[knopers8]

Hi @chiarazampolli yes of course. Can you remind me which major release is this?

[chiarazampolli]

Actually, at the moment we are using v1.123.0, so the bug is not there. But in general, we should understand how to handle data and MC when we use dev/master of O2/O2DPG, but an "old" tag from QC...

[martenole]

Hi @chiarazampolli the bug has been there for a very long time. Also in v1.123.0 it is present. It is just very unlikely to have zero tracklets for a whole TF that's why it appeared only once now. I doubt it will ever happen in PbPb, but still I think it would be better to have the protection in..

[chiarazampolli]

Hello @martenole ,
Was it not introduced here?
martenole@6a6b601

Maybe I am overlooking...
Chiara

[knopers8]

I doubt it will ever happen in PbPb, but still I think it would be better to have the protection in..

In alibi it happened a few nights in a row over the weekend, so it's likely that the bug was introduced recently.

[martenole]

Hello @martenole , Was it not introduced here?

Yes, you are right, sorry. Indeed I introduced the bug in #2037 and checked wrongly for an older version