avoid propagation of muons with zero momentum

[slava77]

This fixes a crash reported in express in 732patch2 in run 234542.
The condition is fairly rare and has numerical precision/randomness nature.

The code was tested in CMSSW_7_3_2_patch2 /test area crash732p2a-234542/
extended reco tests show no differences in monitored quantities.
The crash itself is gone.

Note that debugging was easier with FPEs enabled.

[cmsbuild]

A new Pull Request was created by @slava77 (Slava Krutelyov) for CMSSW_7_3_X.

avoid propagation of muons with zero momentum

It involves the following packages:

RecoMuon/CosmicMuonProducer
TrackPropagation/SteppingHelixPropagator

@cmsbuild, @cvuosalo, @nclopezo, @slava77 can you please review it and eventually sign? Thanks.
@battibass, @abbiendi, @bellan, @rociovilar, @trocino, @bachtis, @venturia this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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@nclopezo you are the release manager for this.
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[slava77]

+1

for #7849 747b543
(tests are as reported in the subjected of the PR)

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes or unless it breaks tests. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @nclopezo, @ktf, @smuzaffar

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @nclopezo, @ktf, @smuzaffar

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7849/2704/summary.html

[cmsbuild]

+1
Tested at: 747b543
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7849/2705/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @nclopezo, @ktf, @smuzaffar

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7849/2705/summary.html

[davidlange6]

+1