improve how HLTPrescaler checks presence of (Stage-2) L1-uGT results [13_1_X]

[missirol]

backport of #41575

PR description:

From the description of #41575:

This PR improves how the HLTPrescaler checks for the availability of the Stage-2 L1-uGT results of BX=0 before accessing them to find the index of the prescale column.

This check is currently done by first calling BXVector::begin(0), but the latter call can in principle result in a runtime error if the content of the BXVector is empty, see here.

The check is updated using BXVector::isEmpty(0), which shouldn't lead to runtime crashes under any circumstances provided #41572 and its backports are integrated.

Merely technical. No changes expected.

PR validation:

None.

If this PR is a backport, please specify the original PR and why you need to backport that PR. If this PR will be backported, please specify to which release cycle the backport is meant for:

#41575

Preemptive fix to a plugin used online in the HLT menu.

[cmsbuild]

A new Pull Request was created by @missirol (Marino Missiroli) for CMSSW_13_1_X.

It involves the following packages:

• HLTrigger/HLTcore (hlt)

@cmsbuild, @missirol, @Martin-Grunewald can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @silviodonato, @fwyzard this is something you requested to watch as well.
@perrotta, @dpiparo, @rappoccio you are the release manager for this.

cms-bot commands are listed here

• Backported from improve how HLTPrescaler checks presence of (Stage-2) L1-uGT results #41575

[missirol]

please test

[cmsbuild]

-1

Failed Tests: RelVals-INPUT
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-84382f/32450/summary.html
COMMIT: b00b191
CMSSW: CMSSW_13_1_X_2023-05-07-0000/el8_amd64_gcc11
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/41576/32450/install.sh to create a dev area with all the needed externals and cmssw changes.

RelVals-INPUT

• 140.046140.046_RunDisplacedJet2022C/step2_RunDisplacedJet2022C.log
• 140.062140.062_RunMuon2022D/step2_RunMuon2022D.log
• 140.065511140.065511_Run3-2023_JetMET2022D_RecoECALOnlyCPU/step2_Run3-2023_JetMET2022D_RecoECALOnlyCPU.log

Comparison Summary

Summary:

• You potentially removed 15 lines from the logs
• Reco comparison results: 16 differences found in the comparisons
• DQMHistoTests: Total files compared: 48
• DQMHistoTests: Total histograms compared: 3460877
• DQMHistoTests: Total failures: 15
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3460840
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 47 files compared)
• Checked 207 log files, 159 edm output root files, 48 DQM output files
• TriggerResults: no differences found

[Martin-Grunewald]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-84382f/32461/summary.html
COMMIT: b00b191
CMSSW: CMSSW_13_1_X_2023-05-07-2300/el8_amd64_gcc11
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/41576/32461/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 4 lines to the logs
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 48
• DQMHistoTests: Total histograms compared: 3460877
• DQMHistoTests: Total failures: 2
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3460853
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 47 files compared)
• Checked 207 log files, 159 edm output root files, 48 DQM output files
• TriggerResults: no differences found

[missirol]

+hlt

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_13_1_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_13_2_X is complete. This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @rappoccio (and backports should be raised in the release meeting by the corresponding L2)

[rappoccio]

+1