From 6c9a974109810a89b28711f0fa8b188a252c90a8 Mon Sep 17 00:00:00 2001
From: rtrimana <rtrimana@uci.edu>
Date: Fri, 19 Jun 2020 11:50:50 -0700
Subject: [PATCH] Bug fix: when state is not found in rGraph, that means the
 state is being visited and this is a loop (self-predecessor).

---
 src/main/gov/nasa/jpf/listener/DPORStateReducer.java | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/main/gov/nasa/jpf/listener/DPORStateReducer.java b/src/main/gov/nasa/jpf/listener/DPORStateReducer.java
index ef0994c..13061d8 100644
--- a/src/main/gov/nasa/jpf/listener/DPORStateReducer.java
+++ b/src/main/gov/nasa/jpf/listener/DPORStateReducer.java
@@ -352,6 +352,10 @@ public class DPORStateReducer extends ListenerAdapter {
       return executionTrace.get(0);
     }
 
+    public TransitionEvent getLastTransition() {
+      return executionTrace.get(executionTrace.size() - 1);
+    }
+
     public HashMap<Integer, ReadWriteSet> getReadWriteFieldsMap() {
       return readWriteFieldsMap;
     }
@@ -421,6 +425,12 @@ public class DPORStateReducer extends ListenerAdapter {
     }
 
     public HashSet<TransitionEvent> getReachableTransitionsAtState(int stateId) {
+      if (!graph.containsKey(stateId)) {
+        // This is a loop from a transition to itself, so just return the current transition
+        HashSet<TransitionEvent> transitionSet = new HashSet<>();
+        transitionSet.add(currentExecution.getLastTransition());
+        return transitionSet;
+      }
       return graph.get(stateId);
     }
 
-- 
2.34.1