From 2dfe0db180d3cfa42df5737ac272cad9938f9c83 Mon Sep 17 00:00:00 2001
From: Fedor Isakov <fisakov@gmail.com>
Date: Tue, 5 Jan 2016 12:44:00 +0100
Subject: [PATCH] Ensure evaluation session is cleared on exit

---
 .../mps/logic/reactor/core/MemEvaluationSession.kt         | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/reactor/Core/src/jetbrains/mps/logic/reactor/core/MemEvaluationSession.kt b/reactor/Core/src/jetbrains/mps/logic/reactor/core/MemEvaluationSession.kt
index 51a09876..41578829 100644
--- a/reactor/Core/src/jetbrains/mps/logic/reactor/core/MemEvaluationSession.kt
+++ b/reactor/Core/src/jetbrains/mps/logic/reactor/core/MemEvaluationSession.kt
@@ -51,7 +51,12 @@ class MemEvaluationSession : EvaluationSession {
             session = MemEvaluationSession(program)
             ourBackend.ourSession.set(session)
 
-            session.launch(myParameters["main"] as ConstraintOccurrence)
+            try {
+                session.launch(myParameters["main"] as ConstraintOccurrence)
+            }
+            finally {
+                ourBackend.ourSession.set(null)
+            }
 
             return session
         }