Index: lucene/contrib/misc/src/java/org/apache/lucene/index/NRTManager.java
===================================================================
--- lucene/contrib/misc/src/java/org/apache/lucene/index/NRTManager.java	(revision 1198594)
+++ lucene/contrib/misc/src/java/org/apache/lucene/index/NRTManager.java	(working copy)
@@ -301,10 +301,14 @@
   public synchronized void close() throws IOException {
     reopenLock.lock();
     try {
-      IOUtils.close(withDeletes, withoutDeletes);
-      newGeneration.signalAll();
+      try {
+        IOUtils.close(withDeletes, withoutDeletes);
+      } finally { // make sure we signal even if close throws an exception
+        newGeneration.signalAll();
+      }
     } finally {
       reopenLock.unlock();
+      assert withDeletes.generation == Long.MAX_VALUE && withoutDeletes.generation == Long.MAX_VALUE;
     }
   }