CSCDigiToRawModule deferences invalid edm::Handle

[Dr15Jones]

The UBSAN build uncovered the following

/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3d0af0c821cc86dc2e95a3561ce9bea6/opt/cmssw/slc7_amd64_gcc820/cms/cmssw/CMSSW_11_2_UBSAN_X_2020-07-24-2300/src/EventFilter/CSCRawToDigi/plugins/CSCDigiToRawModule.cc:172:28: runtime error: reference binding to null pointer of type 'const struct GEMPadDigiClusterCollection'

The problem is here with the variable padDigiClusters which is an edm::Handle
https://github.com/cms-sw/cmssw/blob/master/EventFilter/CSCRawToDigi/plugins/CSCDigiToRawModule.cc#L168-L179

The Handle is only set if useGEMs_ is true. If it is false, than an invalid edm::Handle is deferences and a nullptr is returned via the reference. [See bug report #30915 ]. Once the edm::Handle bug is fixed, this code will fail.

[cmsbuild]

A new Issue was created by @Dr15Jones Chris Jones.

@Dr15Jones, @dpiparo, @silviodonato, @smuzaffar, @makortel, @qliphy can you please review it and eventually sign/assign? Thanks.

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[Dr15Jones]

assign reconstruction

[cmsbuild]

New categories assigned: reconstruction

@slava77,@perrotta,@jpata you have been requested to review this Pull request/Issue and eventually sign? Thanks

[Dr15Jones]

Fixed by #30925

[perrotta]

+1
(see #30916 (comment), thank you @Dr15Jones )

[cmsbuild]

This issue is fully signed and ready to be closed.