Fix crashing bug in reco when run with XML geometry

[cvuosalo]

When reco for the Extended2021 scenario was run with geometry from XML instead of the DB, it was crashing due to missing GEM super chambers. The validation code was referencing GEM super chambers even if they didn't exist, thus causing the crash.

This bug fix adds protection in the validation code to make sure that null or empty objects are not dereferenced.

The issue of the missing GEM super chambers requires further investigation. This PR is just a first step that allows reco to run to completion without crashing. The next step is to examine the plots derived from reco to try to understand what is missing from the GEMs.

PR validation:

The 11634.0_TTbar_14TeV+TTbar_14TeV_TuneCP5_2021 reco step was tested using XML geometry and a second time with DB geometry, and it ran successfully.

No backport is needed.

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-29741/15146

• This PR adds an extra 32KB to repository

[cmsbuild]

A new Pull Request was created by @cvuosalo (Carl Vuosalo) for master.

It involves the following packages:

Validation/MuonGEMDigis
Validation/MuonGEMHits
Validation/MuonGEMRecHits

@andrius-k, @kmaeshima, @schneiml, @cmsbuild, @jfernan2, @fioriNTU can you please review it and eventually sign? Thanks.
@jshlee this is something you requested to watch as well.
@silviodonato, @dpiparo you are the release manager for this.

cms-bot commands are listed here

[cvuosalo]

type bugfix

[cvuosalo]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/6112/console Started: 2020/05/05 22:07

[cvuosalo]

@ianna FYI. I found out that GEM super chambers are missing because reco was crashing when I ran it using XML geometry. This PR prevents the crash but does not address the missing super chambers.

[ianna]

@dildick - FYI

[dildick]

@jshlee Do you know why GEM superchambers are missing? Is it picking up the slice test configuration?

[cmsbuild]

+1
Tested at: 1d01e2b
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d70d06/6112/summary.html
CMSSW: CMSSW_11_1_X_2020-05-05-1100
SCRAM_ARCH: slc7_amd64_gcc820

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d70d06/6112/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 34
• DQMHistoTests: Total histograms compared: 2696239
• DQMHistoTests: Total failures: 43
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2695877
• DQMHistoTests: Total skipped: 319
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 33 files compared)
• Checked 147 log files, 16 edm output root files, 34 DQM output files

[jfernan2]

+1
Only the random L1T known changes

[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 (and backports should be raised in the release meeting by the corresponding L2)

[silviodonato]

+1