decouple EventContent_cff load from general purpose use of Merge.py

[slava77]

This should resolve #22933
The immediate problem is for Configuration/DataProcessing/python/Scenario.py, which defines the T0 config driver for production workflows:

• the Merge.py is needed for file merging functionality of the Scenario.py
• the EventContent_cff has to be also loaded for RECO or similar workflows and is normally supposed to be loaded only after the cms.Process object with a relevant era is created (done in the ConfigBuilder.py)
• In the current state the EventContent_cff is loaded in Merge.py for RECO and similar workflows before cms.Process object is defined. This is a bug.

This fix simply restricts loading of the EventContent_cff in the Merge.py only in merging context for NANO AOD purposes.

Tests:
python $CMSSW_BASE/src/Configuration/DataProcessing/test/RunMerge.py --input-files file:a.root --output-file file:b.root --mergeNANO
and then config dump to see that the result is as expected. The RunMerge is also made aware of mergeNANO.

python $CMSSW_BASE/src/Configuration/DataProcessing/test/RunPromptReco.py --scenario ppEra_Run2_2017_pp_on_XeXe --reco --aod --miniaod --dqmio --global-tag 92X_dataRun2_Express_v7 --lfn=file:raw.root
and then dump to see that _hiCentrality name actually shows up in the keep statements

[cmsbuild]

A new Pull Request was created by @slava77 (Slava Krutelyov) for CMSSW_9_4_X.

It involves the following packages:

Configuration/DataProcessing

@cmsbuild, @franzoni, @fabiocos, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald this is something you requested to watch as well.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

• Backported from decouple EventContent_cff load from general purpose use of Merge.py #22938

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/27450/console Started: 2018/04/12 09:44

[slava77]

backport of #22938

[cmsbuild]

+1
Tested at: 2b4a741
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-22940/27450/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-22940/27450/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 27
• DQMHistoTests: Total histograms compared: 2721493
• DQMHistoTests: Total failures: 106
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2721225
• DQMHistoTests: Total skipped: 162
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0 KiB( 0 files compared)
• Checked 110 log files, 9 edm output root files, 27 DQM output files

[fabiocos]

+operations

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_4_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_10_2_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

+1