Make CSC{AL,CL}CTDigi::getHits() to return by const reference instead of a copy

[makortel]

PR description:

This PR proposes to change CSCCLCTDigi::getHits() to return CSCCLCTDigi::ComparatorContainer (vector of vector of uint16_t) by a const reference instead of a copy. This change fixes a clang warning in Validation/MuonCSCDigis/src/CSCStubMatcher.cc

  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/6038296c716a87387818187cfd4f57eb/opt/cmssw/slc7_amd64_gcc820/cms/cmssw/CMSSW_11_2_CLANG_X_2020-06-14-2300/src/Validation/MuonCSCDigis/src/CSCStubMatcher.cc:140:39: warning: object backing the pointer will be destroyed at the end of the full-expression [-Wdangling-gsl]
           for (const auto& clctComp : (*c).getHits()[layer - 1]) {
                                      ^~~~~~~~~~~~~~
1 warning generated.

https://cmssdt.cern.ch/SDT/cgi-bin/buildlogs/slc7_amd64_gcc820/CMSSW_11_2_CLANG_X_2020-06-14-2300/Validation/MuonCSCDigis

The CSCALCTDigi::getHits() is changed accordingly.

PR validation:

Code compiles, with clang without warnings.

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-30247/16141

• This PR adds an extra 16KB to repository

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

  • File DataFormats/CSCDigi/interface/CSCCLCTDigi.h modified in PR(s): Update accessor in CLCT and LCT data formats #30128

[cmsbuild]

A new Pull Request was created by @makortel (Matti Kortelainen) for master.

It involves the following packages:

DataFormats/CSCDigi

@cmsbuild, @civanch, @mdhildreth can you please review it and eventually sign? Thanks.
@dildick, @ptcox, @rovere this is something you requested to watch as well.
@silviodonato, @dpiparo you are the release manager for this.

cms-bot commands are listed here

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.

• CMSSW_11_2_X_2020-06-15-1100/slc7_amd64_gcc820: https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/7076/console Started: 2020/06/15 17:20

[dildick]

@makortel Thanks for spotting this. There is a similar line here https://github.com/cms-sw/cmssw/blob/master/DataFormats/CSCDigi/interface/CSCALCTDigi.h#L118, which is not throwing a warning as it is not being used in the CSC validation yet, but it should be modified as well.

[cmsbuild]

+1
Tested at: 347a76a
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-385095/7076/summary.html
CMSSW: CMSSW_11_2_X_2020-06-15-1100
SCRAM_ARCH: slc7_amd64_gcc820

[cmsbuild]

Comparison job queued.

[makortel]

Thanks @dildick, I changed that one as well.

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

Pull request #30247 was updated. @cmsbuild, @civanch, @mdhildreth can you please check and sign again.

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.

• CMSSW_11_2_X_2020-06-15-1100/slc7_amd64_gcc820: https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/7084/console Started: 2020/06/15 19:52

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-385095/7076/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 2 differences found in the comparisons
• DQMHistoTests: Total files compared: 36
• DQMHistoTests: Total histograms compared: 2778811
• DQMHistoTests: Total failures: 4
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2778757
• DQMHistoTests: Total skipped: 50
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 35 files compared)
• Checked 152 log files, 16 edm output root files, 36 DQM output files

[cmsbuild]

+1
Tested at: b79e462
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-385095/7084/summary.html
CMSSW: CMSSW_11_2_X_2020-06-15-1100
SCRAM_ARCH: slc7_amd64_gcc820

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-385095/7084/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 2 differences found in the comparisons
• DQMHistoTests: Total files compared: 36
• DQMHistoTests: Total histograms compared: 2778811
• DQMHistoTests: Total failures: 4
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2778757
• DQMHistoTests: Total skipped: 50
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 35 files compared)
• Checked 152 log files, 16 edm output root files, 36 DQM output files

[civanch]

+1

[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