LUCENE-1805: allow CloseableThreadLocal.set(null)

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@803903 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -470,6 +470,10 @@ Bug fixes
     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

src/java/org/apache/lucene/util/CloseableThreadLocal.java

@@ -62,11 +62,7 @@ public class CloseableThreadLocal {
       } else
         return null;
     } else {
-      Object v = weakRef.get();
+      return weakRef.get();
-      // This can never be null, because we hold a hard
-      // reference to the underlying object:
-      assert v != null;
-      return v;
     }
   }
 

src/test/org/apache/lucene/index/TestCloseableThreadLocal.java

@@ -1,20 +0,0 @@
-package org.apache.lucene.index;
-
-import org.apache.lucene.util.CloseableThreadLocal;
-import org.apache.lucene.util.LuceneTestCase;
-
-public class TestCloseableThreadLocal extends LuceneTestCase {
-  public static final String TEST_VALUE = "initvaluetest";
-  
-  public void testInitValue() {
-    InitValueThreadLocal tl = new InitValueThreadLocal();
-    String str = (String)tl.get();
-    assertEquals(TEST_VALUE, str);
-  }
-  
-  public class InitValueThreadLocal extends CloseableThreadLocal {
-    protected Object initialValue() {
-      return TEST_VALUE;
-    } 
-  }
-}

src/test/org/apache/lucene/util/TestCloseableThreadLocal.java

@@ -0,0 +1,50 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.util;
+
+public class TestCloseableThreadLocal extends LuceneTestCase {
+  public static final String TEST_VALUE = "initvaluetest";
+  
+  public void testInitValue() {
+    InitValueThreadLocal tl = new InitValueThreadLocal();
+    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;
+    } 
+  }
+}