Merge pull request #21120 from cms-btv-pog/GhostTrackStateProtection_…

…from-CMSSW_10_0_X_2017-11-01-1100

Added protection for invalid GhostTrackStates

RecoVertex/GhostTrackFitter/src/PositiveSideGhostTrackFitter.cc

@@ -1,6 +1,7 @@
 #include <cmath>
 #include <vector>
 
+#include "FWCore/MessageLogger/interface/MessageLogger.h"
 #include "DataFormats/GeometryVector/interface/GlobalVector.h" 
 #include "DataFormats/GeometryVector/interface/GlobalPoint.h" 
 
@@ -35,13 +36,17 @@ GhostTrackPrediction PositiveSideGhostTrackFitter::fit(
 			GhostTrackState testState = state;
 			testState.linearize(pred, 2. * origin - lambda);
 			double ndof, chi2;
-
-			updater.contribution(prior, testState, ndof, chi2, true);
-			if (ndof > 0. && chi2 < 10.) {
-				state = testState;
-				if (state.weight() != 1.)
-					state.setWeight(3.);
-				done = false;
+
+			if (testState.isValid()) {
+				updater.contribution(prior, testState, ndof, chi2, true);
+				if (ndof > 0. && chi2 < 10.) {
+					state = testState;
+					if (state.weight() != 1.)
+						state.setWeight(3.);
+					done = false;
+				}
+			} else {
+				edm::LogError("InvalidGhostTrackState") << "Invalid GhostTrackState encountered!";
 			}
 		}
 	}