Trying to merge PSSumw with PSSumw failed compatibility test

[vlimant]

faced in Winter25 production :

https://cms-unified.web.cern.ch/cms-unified/report/cmsunified_task_TSG-Run3Winter25GS-00091__v1_T_250209_143056_5163

there is a failure in merging of NANOAOD edm files :

Fatal Exception (Exit code: 8001)
An exception of category 'LogicError' occurred while
[0] Calling InputSource::readRun_
Exception Message:
Trying to merge PSSumw with PSSumw failed compatibility test.

https://cms-unified.web.cern.ch/cms-unified/joblogs/cmsunified_ACDC1_task_TSG-Run3Winter25GS-00091__v1_T_250303_044244_1990/8001/TSG-Run3Winter25NanoAOD-00040_0MergeNANOEDMAODSIMoutput/63897964-33df-4182-ad47-88d3e76c6dfc-0-0-logArchive/job/WMTaskSpace/cmsRun1/

something similar to #43784

[cmsbuild]

cms-bot internal usage

[cmsbuild]

A new Issue was created by @vlimant.

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

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[vlimant]

assign xpog

[cmsbuild]

New categories assigned: xpog

@ftorrresd,@hqucms you have been requested to review this Pull request/Issue and eventually sign? Thanks

[vlimant]

assign generators

[cmsbuild]

New categories assigned: generators

@bbilin,@lviliani,@menglu21,@mkirsano you have been requested to review this Pull request/Issue and eventually sign? Thanks

[Dr15Jones]

Just to add a bit more context, I assume this is NanoAOD?

[vlimant]

indeed. I updated the description

[Dr15Jones]

Given there are multiple reasons why the exception might happen, it would be good to update the exception message to include additional information as to the reason for the failure. E.g.

cmssw/DataFormats/NanoAOD/interface/MergeableCounterTable.h

Lines 73 to 75 in 4eeb0e8

	bool compatible(const VectorColumn<T>& other) {
	return name == other.name && values.size() == other.values.size(); // we don't check the doc, not needed
	}

the VectorColumn class' exception message should include the two sizes.