From 7eebb21135954d2f29974adb6e6a309f4ab5f7d2 Mon Sep 17 00:00:00 2001
From: Dave Parker <dave.x.parker@gmail.com>
Date: Sun, 12 Feb 2012 23:28:58 +0000
Subject: [PATCH] Bugfix: model rebuild avoidance in Prism works ok when there
 are no undefined constants.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@4608 bbc10eb1-c90d-0410-af57-cb519fbb1720
---
 prism/src/prism/Prism.java | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/prism/src/prism/Prism.java b/prism/src/prism/Prism.java
index a72c3210..e0db21b0 100644
--- a/prism/src/prism/Prism.java
+++ b/prism/src/prism/Prism.java
@@ -1430,6 +1430,8 @@ public class Prism implements PrismSettingsListener
 	 */
 	public void setPRISMModelConstants(Values definedMFConstants) throws PrismLangException
 	{
+		if (currentDefinedMFConstants == null && definedMFConstants == null)
+			return;
 		if (currentDefinedMFConstants != null && currentDefinedMFConstants.equals(definedMFConstants))
 			return;