small technical fix in PixelVertexCollectionTrimmer

[missirol]

PR description:

A test of mine with an incorrectly-configured path ended with a segmentation violation from PixelVertexCollectionTrimmer.
This can occur because the latter producer assumes that the input collection of vertices is non-empty (see here).
The PR implements a simple way to avoid the segfault.

PR validation:

Update works as expected in the user test where the crash occurred.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-32919/21146

• This PR adds an extra 12KB to repository

• There are other open Pull requests which might conflict with changes you have proposed:

  • File RecoPixelVertexing/PixelVertexFinding/plugins/PixelVertexCollectionTrimmer.cc modified in PR(s): Patatrack integration - Pixel vertex reconstruction (11/N) #31723, Squash all Patatrack developments on top of CMSSW_11_3_0_pre5 #27983

[cmsbuild]

A new Pull Request was created by @missirol (Marino Missiroli) for master.

It involves the following packages:

RecoPixelVertexing/PixelVertexFinding

@perrotta, @jpata, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@makortel, @felicepantaleo, @GiacomoSguazzoni, @JanFSchulte, @rovere, @VinInn, @ebrondol, @mtosi, @dgulhan this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[perrotta]

please test

[cmsbuild]

-1

Failed Tests: RelVals-INPUT
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b83cc7/12907/summary.html
COMMIT: aac2473
CMSSW: CMSSW_11_3_X_2021-02-15-2300/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/32919/12907/install.sh to create a dev area with all the needed externals and cmssw changes.

RelVals-INPUT

• 4.764.76_ZMuSkim2012D+ZMuSkim2012D+HLTDSKIM2+RECODR1reHLT2+HARVESTDR1reHLT/step2_ZMuSkim2012D+ZMuSkim2012D+HLTDSKIM2+RECODR1reHLT2+HARVESTDR1reHLT.log

Comparison Summary

@slava77 comparisons for the following workflows were not done due to missing matrix map:

• /data/cmsbld/jenkins/workspace/compare-root-files-short-matrix/data/PR-b83cc7/11634.911_TTbar_14TeV+2021_DD4hep+TTbar_14TeV_TuneCP5_GenSim+Digi+Reco+HARVEST+ALCA

Summary:

• No significant changes to the logs found
• Reco comparison results: 2 differences found in the comparisons
• DQMHistoTests: Total files compared: 37
• DQMHistoTests: Total histograms compared: 2750846
• DQMHistoTests: Total failures: 9
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2750815
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 36 files compared)
• Checked 156 log files, 37 edm output root files, 37 DQM output files

[missirol]

(error in the tests is not related to this PR)

[missirol]

Would it be possible to restart the tests?

[slava77]

@cmsbuild please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b83cc7/12961/summary.html
COMMIT: aac2473
CMSSW: CMSSW_11_3_X_2021-02-17-1100/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/32919/12961/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 37
• DQMHistoTests: Total histograms compared: 2750983
• DQMHistoTests: Total failures: 3
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2750958
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 36 files compared)
• Checked 156 log files, 37 edm output root files, 37 DQM output files

[perrotta]

+1

• Simple fix: it adds an empty collection to the event in case of missing/empty input collection
• Jenkins tests pass

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1