Add protection for missing 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

BP in 106X is needed

[cmsbuild]

-code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-33920/22992

• This PR adds an extra 12KB to repository

Code check has found code style and quality issues which could be resolved by applying following patch(s)

• code-format:
  https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-33920/22992/code-format.patch
  e.g. curl https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-33920/22992/code-format.patch | patch -p1
  You can also run scram build code-format to apply code format directly

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-33920/22993

• This PR adds an extra 16KB to repository

[cmsbuild]

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

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

[mariadalfonso]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-f4cfd6/15491/summary.html
COMMIT: fa1de08
CMSSW: CMSSW_12_0_X_2021-05-31-1100/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/33920/15491/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: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 37
• DQMHistoTests: Total histograms compared: 2650486
• DQMHistoTests: Total failures: 6
• DQMHistoTests: Total nulls: 1
• DQMHistoTests: Total successes: 2650457
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: -0.004 KiB( 36 files compared)
• DQMHistoSizes: changed ( 312.0 ): -0.004 KiB MessageLogger/Warnings
• Checked 155 log files, 37 edm output root files, 37 DQM output files
• TriggerResults: no differences found

[mariadalfonso]

+xpog

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 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