Python3: Changes needed to build cmssw with python3 as default

[smuzaffar]

These changes are needed in order to build cmssw with python3 set as default python

[smuzaffar]

please test

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-28031/11957

• This PR adds an extra 24KB to repository

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/2585/console Started: 2019/09/20 11:56

[cmsbuild]

A new Pull Request was created by @smuzaffar (Malik Shahzad Muzaffar) for master.

It involves the following packages:

CondFormats/Serialization
FWCore/Utilities

@ggovi, @smuzaffar, @cmsbuild, @Dr15Jones can you please review it and eventually sign? Thanks.
@makortel, @felicepantaleo, @wddgit, @Martin-Grunewald, @mmusich, @seemasharmafnal 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

[cmsbuild]

+1
Tested at: 792a36f
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-0d1f7f/2585/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-0d1f7f/2585/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 34
• DQMHistoTests: Total histograms compared: 2958092
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2957750
• DQMHistoTests: Total skipped: 341
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 33 files compared)
• Checked 145 log files, 15 edm output root files, 34 DQM output files

[fabiocos]

@ggovi could you please check the DB part? As far as I can see the main change is the need to specify the decoding of strings (@smuzaffar do you confirm ? This looks a sizeable difference compared to python2)

[smuzaffar]

@fabiocos @govvi, yes we have some files with special characters in comments ( e.g files like these

cmssw/CalibFormats/SiPixelObjects/src/PixelBase64.cc

Line 4 in da232d4

Copyright (C) 2004-2008 René Nyffenegger

) so python3 fails to read these types of files in to string. That is why we need encoding. Note that all these special characters are in comments sections so this does not change the generated source file by condformats_serialization_generate.py .

[ggovi]

@smuzaffar thanks a lot.

[ggovi]

+1

[smuzaffar]

@Dr15Jones , any objection on these changes?

[Dr15Jones]

+1

[fabiocos]

@smuzaffar concerning the edmCheckClass tools, these scripts in practice are run within scram build, and I see they run smoothly.

[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. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

+1