ProductNotFound in 546, 547, 548 workflows

[makortel]

Workflows 546, 547, 548 step 2, 3, 3 (respectively) has been failing since CMSSW_12_0_X_2021-04-28-1100 with

%MSG
----- Begin Fatal Exception 28-Apr-2021 15:37:20 CEST-----------------------
An exception of category 'ProductNotFound' occurred while
   [0] Processing  Event run: 1 lumi: 1 event: 1 stream: 1
   [1] Running path 'nanoAOD_step'
   [2] Calling method for module GenVisTauProducer/'genVisTaus'
Exception Message:
Principal::getByToken: Found zero products matching all criteria
Looking for type: std::vector<reco::GenJet>
Looking for module label: tauGenJetsSelectorAllHadronsForNano
Looking for productInstanceName: 

   Additional Info:
      [a] If you wish to continue processing events after a ProductNotFound exception,
add "SkipEvent = cms.untracked.vstring('ProductNotFound')" to the "options" PSet in the configuration.

----- End Fatal Exception -------------------------------------------------
%MSG-w MemoryCheck:  JetFlavourClustering:genJetAK8FlavourAssociation  28-Apr-2021 15:37:20 C

https://cmssdt.cern.ch/SDT/cgi-bin/logreader/slc7_amd64_gcc900/CMSSW_12_0_X_2021-04-28-1100/pyRelValMatrixLogs/run/546.0_DYToLL_M-50_13TeV_pythia8+DYToLL_M-50_13TeV_pythia8+NANOGENFromGen/step2_DYToLL_M-50_13TeV_pythia8+DYToLL_M-50_13TeV_pythia8+NANOGENFromGen.log#/

[makortel]

assign generators, xpog

[cmsbuild]

New categories assigned: generators,xpog

@mkirsano,@SiewYan,@fgolf,@mariadalfonso,@alberto-sanchez,@gouskos,@agrohsje,@GurpreetSinghChahal you have been requested to review this Pull request/Issue and eventually sign? Thanks

[cmsbuild]

A new Issue was created by @makortel Matti Kortelainen.

@Dr15Jones, @dpiparo, @silviodonato, @smuzaffar, @makortel, @qliphy can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[makortel]

#33522 (merged in that IB) seems like a plausible cause

[mariadalfonso]

@mbluj @kdlong
can you help here ?

[mariadalfonso]

we have this visible tau sequence also in the nanoGEN, we just need to import the changes more transparently

cmssw/PhysicsTools/NanoAOD/python/nanogen_cff.py

Line 29 in 6d2f660

tauGenJets+

[kdlong]

This looks like the likely culprit. Best would be to divide the tauMC statement into the genOnly pieces so the actual sequence can be added to NanoGen. Something like:

tauMCgen = cms.Sequence(tauGenJetsForNano + tauGenJetsSelectorAllHadronsForNano + genVisTaus + genVisTauTable)
tauMC = cms.Sequence(tauMCGen + tausMCMatchLepTauForTable + tausMCMatchHadTauForTable + tauMCTable)

then schedule tauMCgen in the NanoGen sequence. If someone else can actually implement this (@dteague ?) that would be great.

[mbluj]

I think I can take it.
@kdlong, thanks for suggestion, I'll follow it.

[mbluj]

Fixes implemented in PR #33586 (master) and #33590 (106X).

[mariadalfonso]

+xpog