[DO-NOT merge] Revert "Enforce Modifier consistency between Process instances"

[silviodonato]

Reverts #37903.
This PR is needed to run the HLT menu with a L1 trigger emulator.

hltGetConfiguration /dev/CMSSW_12_4_0/GRun/V13 --full --offline --no-output --data --process MYHLT --type GRun --unprescale --globaltag auto:run3_hlt --max-events -1 --l1 L1Menu_Collisions2022_v1_0_0_xml --customise HLTrigger/Configuration/customizeHLTforCMSSW.customiseFor2018Input  --l1-emulator uGT > hlt_data.py

edmConfigDump hlt_data.py > hlt_data_dump.py

gives

Traceback (most recent call last):
  File "/cvmfs/cms.cern.ch/slc7_amd64_gcc10/cms/cmssw/CMSSW_12_4_0_pre4/bin/slc7_amd64_gcc10/edmConfigDump", line 26, in <module>
    loader.exec_module(mod)
  File "<frozen importlib._bootstrap_external>", line 850, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
  File "hlt_data.py", line 83078, in <module>
    process = L1REPACK(process,"uGT")
  File "/cvmfs/cms.cern.ch/slc7_amd64_gcc10/cms/cmssw/CMSSW_12_4_0_pre4/python/HLTrigger/Configuration/CustomConfigs.py", line 156, in L1REPACK
    l1repack = cms.Process('L1REPACK', Run3)
  File "/cvmfs/cms.cern.ch/slc7_amd64_gcc10/cms/cmssw/CMSSW_12_4_0_pre4/python/FWCore/ParameterSet/Config.py", line 156, in __init__
    raise RuntimeError("The Process {} tried to redefine which Modifiers to use after another Process was already started".format(name))
RuntimeError: The Process L1REPACK tried to redefine which Modifiers to use after another Process was already started

@cms-sw/hlt-l2 we should find a solution to fix https://github.com/cms-sw/cmssw/blob/master/HLTrigger/Configuration/python/CustomConfigs.py#L177

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-37996/30071

• This PR adds an extra 12KB to repository

[cmsbuild]

A new Pull Request was created by @silviodonato (Silvio Donato) for master.

It involves the following packages:

• FWCore/ParameterSet (core)

@cmsbuild, @smuzaffar, @Dr15Jones, @makortel can you please review it and eventually sign? Thanks.
@makortel, @wddgit this is something you requested to watch as well.
@perrotta, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[missirol]

hltGetConfiguration /dev/CMSSW_12_4_0/GRun/V13 --full --offline --no-output --data --process MYHLT --type GRun --unprescale --globaltag auto:run3_hlt --max-events -1 --l1 L1Menu_Collisions2022_v1_0_0_xml --customise HLTrigger/Configuration/customizeHLTforCMSSW.customiseFor2018Input --l1-emulator uGT > hlt_data.py

I agree it's worth trying to improve it from the HLT side (although the solution won't be obvious, otherwise it would have been found already in #37740).

One possible workaround is to specify hltGetConfiguration --eras Run3 such that the "main" Process uses the same modifiers as the "internal" Process for L1REPACK (which is hard-coded to Run3). The disadvantage is that this will force the additional customisations in --customise to run with the Run3 modifiers always. In this case, the additional customisation is not era-dependent, so there is no issue with using --eras Run3 (reminder to self: the HLT menu itself does not make use of Eras).

[Martin-Grunewald]

The other possibility is to split L1T and HLT into two separate steps, I think Sam mentioned this.
With real Run3 data of course all will be fine as then we do not need to process Run2 data anymore.

[Dr15Jones]

Instead of reverting the the change, it is possible to explicitly 'reset' the test by doing

cms.Process._firstProcess = True

before building the 2nd Process object.

[Dr15Jones]

So change

cmssw/HLTrigger/Configuration/python/CustomConfigs.py

Line 177 in 0317013

l1repack = cms.Process('L1REPACK', Run3)

to

cms.Process._firstProcess = True
l1repack = cms.Process('L1REPACK', Run3)

[perrotta]

@silviodonato which are the plans for this PR, which is stuck since almost 9 months

[smuzaffar]

Milestone for this pull request has been moved to CMSSW_14_0_X.Please open a backport if it should also go in to CMSSW_13_3_X.

[makortel]

@cms-sw/hlt-l2 Is this PR still useful?

[cmsbuild]

Milestone for this pull request has been moved to CMSSW_14_1_X. Please open a backport if it should also go in to CMSSW_14_0_X.

[makortel]

@cms-sw/hlt-l2 I suppose this PR could be closed now?

[Martin-Grunewald]

I have not seen any error reports like the one starting this PR, recently.

[makortel]

Thanks @Martin-Grunewald

[makortel]

-core

[makortel]

@cmsbuild, please close