Mu2eKinKal: exception raised in KinKal::TimeRange constructor for regrow_kl.fcl

[RobMina]

I encountered an exception when running Production/JobConfig/reco/regrow_kl.fcl, it was "Invalid Time Range" in KinKal::TimeRange constructor:
#1 0x00007ffff214af99 in KinKal::TimeRange::TimeRange (this=this@entry=0x7fffffff4e60, begin=, end=end@entry=11456.136692011529, ordered=true) at /cvmfs/mu2e.opensciencegrid.org/spackages/241207/spack/var/spack/environments/muse-al9-prof-e29-p106/.spack-env/view/include/KinKal/General/TimeRange.hh:17
#2 0x00007ffff2197f41 in mu2e::KKExtrap::toTrackerPerimeterKinKal::KinematicLine(mu2e::KKTrackKinKal::KinematicLine&) const::{lambda(KinKal::TimeDir)#1}::operator()(KinKal::TimeDir) const (__closure=__closure@entry=0x7fffffff50b0, tdir=, tdir@entry=KinKal::TimeDir::backwards) at /cvmfs/mu2e.opensciencegrid.org/spackages/241207/spack/var/spack/environments/muse-al9-prof-e29-p106/.spack-env/view/include/KinKal/General/TimeRange.hh:23
#3 0x00007ffff219858f in mu2e::KKExtrap::toTrackerPerimeterKinKal::KinematicLine (this=this@entry=0xde9650, ktrk=...) at ./Offline/Mu2eKinKal/inc/KKExtrap.hh:174
#4 0x00007ffff21c465b in mu2e::KKExtrap::extrapolateKinKal::KinematicLine (this=0xde9650, ktrk=...) at ./Offline/Mu2eKinKal/inc/KKExtrap.hh:89
#5 0x00007ffff215b030 in mu2e::RegrowKinematicLine::produce (this=0xde4680, event=...) at Offline/Mu2eKinKal/src/RegrowKinematicLine_module.cc:239

The Offline call is in toTrackerPerimeter here:

Offline/Mu2eKinKal/inc/KKExtrap.hh

Line 159 in 0ef02a6

TimeRange(tref,ftraj.range().end()) : TimeRange(ftraj.range().begin(),tref);

[brownd1978]

"Invalid Time Range" is always an indication of a deeper problem. Masking it by allowing an unphysical range will just delay the exception or cause downstream inconsistencies.

ToTrackerPerimeter assumes the track has a valid, in-range intersection with TT_Mid. That is true for essentially all LoopHelix tracks, but not necessarily for CentralHelix or KinematicLine. The minimum fix is to test TT_Mid intersection validity before calling, and to provide an alternative (perhaps the t0 location) to seed the perimeter search if not.