[10_2_X] Fix a discrepancy in Puppi weights when running on MiniAOD w/ useExistingWeights=False

[hqucms]

PR description:

Backport of #28033 for 10_2_X.
This is a minimal fix without the code simplification in #28033.

The discrepancy happens only when remaking puppi from miniAOD in analysis setup or other non-standard workflows, with useExistingWeights=False, and is fixed in this PR.

Standard miniAOD or nanoAOD productions are not affected.

[cmsbuild]

A new Pull Request was created by @hqucms (Huilin Qu) for CMSSW_10_2_X.

It involves the following packages:

CommonTools/PileupAlgos

@perrotta, @cmsbuild, @santocch, @slava77 can you please review it and eventually sign? Thanks.
@rappoccio, @ahinzmann, @riga, @jdolen, @gkasieczka, @clelange this is something you requested to watch as well.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

• Backported from Fix a discrepancy in Puppi weights when running on MiniAOD w/ useExistingWeights=False #28033

[perrotta]

backport of #28033

[perrotta]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/2927/console Started: 2019/10/14 18:52

[cmsbuild]

+1
Tested at: e8df495
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-e9b5e7/2927/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-e9b5e7/2927/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 31
• DQMHistoTests: Total histograms compared: 3007468
• DQMHistoTests: Total failures: 2
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3007276
• DQMHistoTests: Total skipped: 190
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 30 files compared)
• Checked 129 log files, 14 edm output root files, 31 DQM output files

[slava77]

+1

for #28170 e8df495

• this is equivalent to changes proposed for 106X in [10_6_X] Fix a discrepancy in Puppi weights when running on MiniAOD w/ useExistingWeights=False #28169 acf7bb8
• this is a limited backport of Fix a discrepancy in Puppi weights when running on MiniAOD w/ useExistingWeights=False #28033 done in a way that should not affect the standard AOD->miniAOD and nanoAOD workflows and should make a difference only for cases of remaking puppi from miniAOD in analysis setup or other non-standard workflows
• jenkins tests pass and comparisons with the baseline show no (relevant) differences

@fabiocos my comments in the ORP were based on the #28033 ; after some more careful look in this PR, I see that it should be OK for integration

@hqucms please edit the PR description to clarify that the standard miniAOD or nanoAOD production are not affected

[santocch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_2_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_11_0_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

+1