Bug fix in HLTJetCollectionsVBFFilter

[wddgit]

Fix a bug where the code is using the index
into the RefVector where the index into the
collection is expected. This will result in
Ref's to the wrong element being created.

[cmsbuild]

A new Pull Request was created by @wddgit (W. David Dagenhart) for CMSSW_7_4_X.

Bug fix in HLTJetCollectionsVBFFilter

It involves the following packages:

HLTrigger/JetMET

@Martin-Grunewald, @perrotta, @cmsbuild, @nclopezo, @fwyzard can you please review it and eventually sign? Thanks.
@Martin-Grunewald this is something you requested to watch as well.
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[wddgit]

Note I am not familiar with this code. It is possible
this code is not used for anything, but if it is
used then it is likely this bug are creating
incorrect results. I did not test this beyond
making sure the fix compiles and it would be a
good idea for someone familiar with this to take
a look at it.

The Ref constructor used by this code will be deleted
from the Core code in a pull request which will be
submitted within the next few days. That is why I
noticed this. That pull request will depend on this
one getting merged first.

To illustrate the problem more clearly, the RefVector
might have 5 entries and the TCollection might have
1000 jets. The 3rd element of the RefVector might
reference the 500th jet. The existing call to the constructor
is passing an index into the RefVector when an index into
the TCollection is expected, In this example, passing 3
instead of 500.

[Martin-Grunewald]

Thanks for catching this!

[Martin-Grunewald]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 7cb6521
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7457/2236/summary.html

[Martin-Grunewald]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes (tests are also fine). This pull request will be automatically merged.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7457/2236/summary.html