Fix issue with lock file when org.apache.lucene.lockDir and java.io.tmpdir are not set

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@230939 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/lucene/store/FSDirectory.java

@@ -146,6 +146,13 @@ public class FSDirectory extends Directory {
     else {
       lockDir = new File(LOCK_DIR);
     }
+    // Ensure that lockDir exists and is a directory.
+    if (!lockDir.exists()) {
+      if (!lockDir.mkdirs())
+        throw new IOException("Cannot create directory: " + lockDir);
+    } else if (!lockDir.isDirectory()) {
+      throw new IOException("Found regular file where directory expected: " + lockDir);
+    }
     if (create) {
       create();
     }

src/test/org/apache/lucene/index/store/FSDirectoryTest.java

@@ -0,0 +1,149 @@
+package org.apache.lucene.index.store;
+
+/**
+ * Copyright 2005 The Apache Software Foundation
+ *
+ * Licensed 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.
+ */
+
+import java.io.File;
+import java.io.IOException;
+
+import junit.framework.TestCase;
+
+import org.apache.lucene.analysis.standard.StandardAnalyzer;
+import org.apache.lucene.index.IndexWriter;
+
+/**
+ * Test to illustrate the problem found when trying to open an IndexWriter in
+ * a situation where the the property <code>org.apache.lucene.lockDir</code>
+ * was not set and the one specified by <code>java.io.tmpdir</code> had been
+ * set to a non-existent path. What I observed is that this combination of
+ * conditions resulted in a <code>NullPointerException</code> being thrown in
+ * the <code>create()</code> method in <code>FSDirectory</code>, where
+ * <code>files.length</code> is de-referenced, but <code>files</code> is
+ * </code>null</code>.
+ *
+ * @author Michael Goddard
+ */
+
+public class FSDirectoryTest extends TestCase {
+
+    /**
+     * What happens if the Lucene lockDir doesn't exist?
+     *
+     * @throws Exception
+     */
+    public void testNonExistentTmpDir() throws Exception {
+        orgApacheLuceneLockDir = System.setProperty(
+                "org.apache.lucene.lockDir", NON_EXISTENT_DIRECTORY);
+        String exceptionClassName = openIndexWriter();
+        if (exceptionClassName == null
+                || exceptionClassName.equals("java.io.IOException"))
+            assertTrue(true);
+        else
+            fail("Caught an unexpected Exception");
+    }
+
+    /**
+     * What happens if the Lucene lockDir is a regular file instead of a
+     * directory?
+     *
+     * @throws Exception
+     */
+    public void testTmpDirIsPlainFile() throws Exception {
+        shouldBeADirectory = new File(NON_EXISTENT_DIRECTORY);
+        shouldBeADirectory.createNewFile();
+        String exceptionClassName = openIndexWriter();
+        if (exceptionClassName == null
+                || exceptionClassName.equals("java.io.IOException"))
+            assertTrue(true);
+        else
+            fail("Caught an unexpected Exception");
+    }
+
+    public static final String FILE_SEP = System.getProperty("file.separator");
+
+    public static final String NON_EXISTENT_DIRECTORY = System
+            .getProperty("java.io.tmpdir")
+            + FILE_SEP + "highly_improbable_directory_name";
+
+    public static final String TEST_INDEX_DIR = System
+            .getProperty("java.io.tmpdir")
+            + FILE_SEP + "temp_index";
+
+    private String orgApacheLuceneLockDir;
+
+    private File shouldBeADirectory;
+
+    public void tearDown() {
+        if (orgApacheLuceneLockDir != null)
+            System.setProperty("org.apache.lucene.lockDir",
+                    orgApacheLuceneLockDir);
+        if (shouldBeADirectory != null && shouldBeADirectory.exists()) {
+            try {
+                shouldBeADirectory.delete();
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+        File deletableIndex = new File(TEST_INDEX_DIR);
+        if (deletableIndex.exists())
+            try {
+                rmDir(deletableIndex);
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+    }
+
+    /**
+     * Open an IndexWriter<br>
+     * Catch any (expected) IOException<br>
+     * Close the IndexWriter
+     */
+    private static String openIndexWriter() {
+        IndexWriter iw = null;
+        String ret = null;
+        try {
+            iw = new IndexWriter(TEST_INDEX_DIR, new StandardAnalyzer(), true);
+        } catch (IOException e) {
+            ret = e.toString();
+            e.printStackTrace();
+        } catch (NullPointerException e) {
+            ret = e.toString();
+            e.printStackTrace();
+        } finally {
+            if (iw != null) {
+                try {
+                    iw.close();
+                } catch (IOException ioe) {
+                    // ignore this
+                }
+            }
+        }
+        return ret;
+    }
+
+    private static void rmDir(File dirName) throws Exception {
+        if (dirName.exists()) {
+            if (dirName.isDirectory()) {
+                File[] contents = dirName.listFiles();
+                for (int i = 0; i < contents.length; i++)
+                    rmDir(contents[i]);
+                dirName.delete();
+            } else {
+                dirName.delete();
+            }
+        }
+	}
+}