Enforce that Process can have at most one Schedule object, and the label must be schedule

[makortel]

There should be 0 or 1 cms.Schedule objects in the cms.Process, and the label of the cms.Schedule should be schedule.

Issue #35624 made it apparent that ConfigBuilder and HLT menus have been using cms.Schedule object labelled HLTSchedule for a long time. We should look into expressing the desired behavior with the label process.schedule, after which we could enforce the rule.

[cmsbuild]

A new Issue was created by @makortel Matti Kortelainen.

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

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[makortel]

assign core, operations, hlt

[cmsbuild]

New categories assigned: operations,core,hlt

@fabiocos,@qliphy,@davidlange6,@missirol,@Dr15Jones,@smuzaffar,@perrotta,@makortel,@Martin-Grunewald you have been requested to review this Pull request/Issue and eventually sign? Thanks

[makortel]

@cms-sw/hlt-l2 I'd like to first understand if the cms.Schedule label of HLTSchedule has any specific meaning in all the other uses of HLT menus than in conjunction with ConfigBuilder (e.g. use in the online farm, ConfDB)?

[Martin-Grunewald]

HLTSchedule is used in various places - see:
https://cmssdt.cern.ch/lxr/search?%21v=CMSSW_12_1_X_2021-10-24-2300&_filestring=&_string=HLTSchedule&_casesensitive=1
It is created by ConfDb, based on the list of all paths, when extracting the HLT menu python dumps for the release located in HLTrigger/Configuration/test and ../python.

[makortel]

Thanks @Martin-Grunewald, I was expecting to see HLTSchedule in many places within CMSSW.

Do I understand correctly that the HLTSchedule name gets added by the ConfDB code? That would add a complication to a migration, but it would still seem possible to do (e.g. I would imagine it to be possible to rename HLTSchedule to schedule in the customization functions that are applied to the fragment in the HLT menu dumps when they are loaded into cms.Process).

[Martin-Grunewald]

HLTSchedule is written here: https://github.com/cms-sw/hlt-confdb/blob/confdbv3/src/confdb/converter/python/PythonConfigurationWriter.java#L217
so I presume its name/label can be changed...