From 55118b6b311ce271a422fa991f8997fccec0f890 Mon Sep 17 00:00:00 2001
From: Dave Parker <dave.x.parker@gmail.com>
Date: Fri, 23 Oct 2020 09:16:20 +0100
Subject: [PATCH] ChoiceActionsSimple bugfix (copy constructor with mismatched
 arrays sizes).

---
 prism/src/explicit/ChoiceActionsSimple.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/prism/src/explicit/ChoiceActionsSimple.java b/prism/src/explicit/ChoiceActionsSimple.java
index 31e83477..2184799a 100644
--- a/prism/src/explicit/ChoiceActionsSimple.java
+++ b/prism/src/explicit/ChoiceActionsSimple.java
@@ -79,13 +79,15 @@ public class ChoiceActionsSimple
 	{
 		actions = null;
 		if (cas.actions != null) {
-			int numStates = cas.actions.size();
+			// NB: permut.length is a more reliable source of numStates
+			// since cas.actions may be undersized
+			int numStates = permut.length;
 			actions = new ArrayList<ArrayList<Object>>(numStates);
 			for (int s = 0; s < numStates; s++) {
 				actions.add(null);
 			}
 			for (int s = 0; s < numStates; s++) {
-				if (cas.actions.get(s) != null) {
+				if (s < cas.actions.size() && cas.actions.get(s) != null) {
 					actions.set(permut[s], new ArrayList<>(cas.actions.get(s)));
 				}
 			}