ITS: add extra protection if no tracklets were produced in ROF

Signed-off-by: Felix Schlepper <felix.schlepper@cern.ch>

Author: f3sch

Detectors/ITSMFT/ITS/tracking/include/ITStracking/TimeFrame.h

@@ -593,7 +593,7 @@ inline gsl::span<int> TimeFrame<nLayers>::getExclusiveNTrackletsCluster(int rofI
 template <int nLayers>
 inline gsl::span<Tracklet> TimeFrame<nLayers>::getFoundTracklets(int rofId, int combId)
 {
-  if (rofId < 0 || rofId >= mNrof) {
+  if (rofId < 0 || rofId >= mNrof || mTracklets[combId].empty()) {
     return {};
   }
   auto startIdx{mNTrackletsPerROF[combId][rofId]};

Detectors/ITSMFT/ITS/tracking/src/VertexerTraits.cxx

@@ -326,6 +326,9 @@ void VertexerTraits::computeTrackletMatching(const int iteration)
           if (iteration && (int)mTimeFrame->getPrimaryVertices(pivotRofId).size() > mVrtParams[iteration].vertPerRofThreshold) {
             continue;
           }
+          if (mTimeFrame->getFoundTracklets(pivotRofId, 0).empty()) {
+            continue;
+          }
           mTimeFrame->getLines(pivotRofId).reserve(mTimeFrame->getNTrackletsCluster(pivotRofId, 0).size());
           bounded_vector<uint8_t> usedTracklets(mTimeFrame->getFoundTracklets(pivotRofId, 0).size(), false, mMemoryPool.get());
           short startROF{std::max((short)0, static_cast<short>(pivotRofId - mVrtParams[iteration].deltaRof))};