Problem in DQM sequence and postSequence duplicate check in ConfigBuilder

[makortel]

While investigating the ConfigBuilder code that lead to #42833, we noticed this piece of code in prepare_DQM() function

cmssw/Configuration/Applications/python/ConfigBuilder.py

Lines 2075 to 2078 in d9efda5

	for (i,_sequence) in enumerate(postSequenceList):
	#Fix needed to avoid duplication of sequences not defined in autoDQM or without a PostDQM
	if (sequenceList[i]==postSequenceList[i]):
	continue

raises an exception if the sequenceList has fewer elements than the postSequenceList. This behavior makes unit testing difficult as the duplicate removal (lines 2054-2056) is done only for sequenceList (after which it has fewer elements than postSequenceList). A workaround in #42833 was to modify autoDQM, but that is more of a hack than a solution.

The code snippet above was added in #28113

[cmsbuild]

A new Issue was created by @makortel Matti Kortelainen.

@Dr15Jones, @rappoccio, @smuzaffar, @makortel, @sextonkennedy, @antoniovilela can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[makortel]

assign operations, dqm

[cmsbuild]

New categories assigned: operations,dqm

@fabiocos,@tjavaid,@davidlange6,@micsucmed,@nothingface0,@rvenditti,@rappoccio,@emanueleusai,@syuvivida,@antoniovilela,@pmandrik you have been requested to review this Pull request/Issue and eventually sign? Thanks