Store variable names in ROOT GBRForest files

[Dr15Jones]

PR description:

Added storing and retrieving variable names from files.

PR validation:

Code compiles. Running a job that uses the original xml files still works.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-38091/30183

• This PR adds an extra 12KB to repository

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for master.

It involves the following packages:

• CommonTools/MVAUtils (reconstruction)

@jpata, @cmsbuild, @clacaputo, @slava77 can you please review it and eventually sign? Thanks.
@perrotta, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[Dr15Jones]

please test

[Dr15Jones]

So I converted the files in RecoEgamma/ElectronIdentification/data/Spring16_HZZ_V1 to be their ROOT equivalents (using this PR), changed the RecoEgamma/ElectronIdentification/python/Identification/mvaElectronID_Spring16_HZZ_V1_cff.py to point to the new files and ran step4 of workflow 11834.21. The files were read (tested using strace) and the job completed just fine.

[swagata87]

thanks @Dr15Jones

• related to convert MVA models for electronMVAValueMapProducer from XML to ROOT #37867 and MVA xml file reading in createGBRForest is longest time in initializing PAT job #38089
  (tagging the related issues in this PR so that necessary PRs/issues can be found easily afterwards)

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-b9144c/25008/summary.html
COMMIT: c65bc65
CMSSW: CMSSW_12_5_X_2022-05-25-1100/el8_amd64_gcc10
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/38091/25008/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: 50
• DQMHistoTests: Total histograms compared: 3650985
• DQMHistoTests: Total failures: 8
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3650955
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 49 files compared)
• Checked 208 log files, 45 edm output root files, 50 DQM output files
• TriggerResults: no differences found

[clacaputo]

+reconstruction

• technical PR
• no reco 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. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[qliphy]

+1