[BP 10_6_X] Add protection for missing L1 handleExtResults

[gouskos]

Adds a protection against the error:

A std::exception was thrown.
vector::_M_range_check: __n (which is 0) >= this->size() (which is 0)

Happening due to empty handleExtResults. This is a rare case.
More details in:
https://its.cern.ch/jira/browse/CMSCOMPPR-17789

Validated on the affected events:
RECO --conditions 106X_dataRun2_v32 --customise Configuration/DataProcessing/Utils.addMonitoring --datatier NANOAOD --era Run2_2017,run2_nanoAOD_106Xv1 --eventcontent NANOEDMAOD --filein placeholder.root --fileout file:ReReco-Run2017E-JetHT-UL2017_MiniAODv1_NanoAODv2-00002.root --nThreads 2 --no_exec --python_filename ReReco-Run2017E-JetHT-UL2017_MiniAODv1_NanoAODv2-00002_0_cfg.py --scenario pp --step NANO --data

file on which we should be able to reproduce the crash at:

Processing Event run: 304197 lumi: 1 event: 875064
root://xrootd.echo.stfc.ac.uk//store/data/Run2017E/JetHT/MINIAOD/09Aug2019_UL2017-v1/30000/457A4F7E-DEEB-DB40-AE94-3687A974F426.root

This PR is a backport of Add protection for missing handleExtResults

[cmsbuild]

A new Pull Request was created by @gouskos for CMSSW_10_6_X.

It involves the following packages:

PhysicsTools/NanoAOD

@cmsbuild, @mariadalfonso, @gouskos, @fgolf can you please review it and eventually sign? Thanks.
@gpetruc, @swertz 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

• Backported from Add protection for missing handleExtResults #33920

[mariadalfonso]

backport of #33920

[mariadalfonso]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6e6ebe/15495/summary.html
COMMIT: 6f21678
CMSSW: CMSSW_10_6_X_2021-05-31-2300/slc7_amd64_gcc700
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/33924/15495/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: 35
• DQMHistoTests: Total histograms compared: 3215543
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3215208
• DQMHistoTests: Total skipped: 334
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 34 files compared)
• Checked 143 log files, 29 edm output root files, 35 DQM output files
• TriggerResults: no differences found

[mariadalfonso]

+xpog

as master this PR fix a very rare crash in production, no changes as expected from the tests

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_6_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_12_0_X is complete. 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