Index: CHANGES.txt
===================================================================
--- CHANGES.txt	(revision 803896)
+++ CHANGES.txt	(working copy)
@@ -470,6 +470,10 @@
     of the instances are correct.  
     (Mike McCandless, Mark Miller, Michael Busch)
 
+22. LUCENE-1805: CloseableThreadLocal did not allow a null Object in get(), 
+    although it does allow it in set(Object). Fix get() to not assert the object
+    is not null. (Shai Erera via Mike McCandless)
+
 New features
 
  1. LUCENE-1411: Added expert API to open an IndexWriter on a prior
Index: src/test/org/apache/lucene/index/TestCloseableThreadLocal.java
===================================================================
--- src/test/org/apache/lucene/index/TestCloseableThreadLocal.java	(revision 803896)
+++ src/test/org/apache/lucene/index/TestCloseableThreadLocal.java	(working copy)
@@ -11,7 +11,23 @@
     String str = (String)tl.get();
     assertEquals(TEST_VALUE, str);
   }
-  
+
+  public void testNullValue() throws Exception {
+    // Tests that null can be set as a valid value (LUCENE-1805). This
+    // previously failed in get().
+    CloseableThreadLocal ctl = new CloseableThreadLocal();
+    ctl.set(null);
+    assertNull(ctl.get());
+  }
+
+  public void testDefaultValueWithoutSetting() throws Exception {
+    // LUCENE-1805: make sure default get returns null,
+    // twice in a row
+    CloseableThreadLocal ctl = new CloseableThreadLocal();
+    assertNull(ctl.get());
+    assertNull(ctl.get());
+  }
+
   public class InitValueThreadLocal extends CloseableThreadLocal {
     protected Object initialValue() {
       return TEST_VALUE;
Index: src/java/org/apache/lucene/util/CloseableThreadLocal.java
===================================================================
--- src/java/org/apache/lucene/util/CloseableThreadLocal.java	(revision 803896)
+++ src/java/org/apache/lucene/util/CloseableThreadLocal.java	(working copy)
@@ -62,11 +62,7 @@
       } else
         return null;
     } else {
-      Object v = weakRef.get();
-      // This can never be null, because we hold a hard
-      // reference to the underlying object:
-      assert v != null;
-      return v;
+      return weakRef.get();
     }
   }