HDFS-5228. The RemoteIterator returned by DistributedFileSystem.listFiles may throw NullPointerException. Contributed by szetszwo and cnauroth

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1525828 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -952,6 +952,9 @@ Release 2.1.0-beta - 2013-08-22
     HDFS-5016. Deadlock in pipeline recovery causes Datanode to be marked dead.
     (suresh)
 
+    HDFS-5228. The RemoteIterator returned by DistributedFileSystem.listFiles
+    may throw NullPointerException.  (szetszwo and cnauroth via szetszwo)
+
   BREAKDOWN OF HDFS-347 SUBTASKS AND RELATED JIRAS
 
     HDFS-4353. Encapsulate connections to peers in Peer and PeerServer classes.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -713,6 +713,7 @@ public class DistributedFileSystem extends FileSystem {
   protected RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path p,
       final PathFilter filter)
   throws IOException {
+    final Path absF = fixRelativePart(p);
     return new RemoteIterator<LocatedFileStatus>() {
       private DirectoryListing thisListing;
       private int i;
@@ -722,7 +723,7 @@ public class DistributedFileSystem extends FileSystem {
       { // initializer
         // Fully resolve symlinks in path first to avoid additional resolution
         // round-trips as we fetch more batches of listings
-        src = getPathName(resolvePath(p));
+        src = getPathName(resolvePath(absF));
         // fetch the first batch of entries in the directory
         thisListing = dfs.listPaths(src, HdfsFileStatus.EMPTY_NAME, true);
         statistics.incrementReadOps(1);
@@ -736,7 +737,7 @@ public class DistributedFileSystem extends FileSystem {
         while (curStat == null && hasNextNoFilter()) {
           LocatedFileStatus next = 
               ((HdfsLocatedFileStatus)thisListing.getPartialListing()[i++])
-              .makeQualifiedLocated(getUri(), p);
+              .makeQualifiedLocated(getUri(), absF);
           if (filter.accept(next.getPath())) {
             curStat = next;
           }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDistributedFileSystem.java

@@ -31,8 +31,10 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.URI;
 import java.security.PrivilegedExceptionAction;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.EnumSet;
+import java.util.List;
 import java.util.Random;
 
 import org.apache.commons.lang.ArrayUtils;
@@ -47,9 +49,11 @@ import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileChecksum;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.LocatedFileStatus;
 import org.apache.hadoop.fs.MD5MD5CRC32FileChecksum;
 import org.apache.hadoop.fs.Options.ChecksumOpt;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.VolumeId;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.web.WebHdfsFileSystem;
@@ -226,7 +230,7 @@ public class TestDistributedFileSystem {
       final long millis = Time.now();
 
       {
-        DistributedFileSystem dfs = (DistributedFileSystem)cluster.getFileSystem();
+        final DistributedFileSystem dfs = cluster.getFileSystem();
         dfs.dfs.getLeaseRenewer().setGraceSleepPeriod(grace);
         assertFalse(dfs.dfs.getLeaseRenewer().isRunning());
   
@@ -326,7 +330,7 @@ public class TestDistributedFileSystem {
       }
 
       {
-        DistributedFileSystem dfs = (DistributedFileSystem)cluster.getFileSystem();
+        final DistributedFileSystem dfs = cluster.getFileSystem();
         assertFalse(dfs.dfs.getLeaseRenewer().isRunning());
 
         //open and check the file
@@ -835,4 +839,25 @@ public class TestDistributedFileSystem {
     }
   }
   
+  @Test(timeout=60000)
+  public void testListFiles() throws IOException {
+    Configuration conf = new HdfsConfiguration();
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
+    
+    try {
+      DistributedFileSystem fs = cluster.getFileSystem();
+  
+      final Path relative = new Path("relative");
+      fs.create(new Path(relative, "foo")).close();
+  
+      final List<LocatedFileStatus> retVal = new ArrayList<LocatedFileStatus>();
+      final RemoteIterator<LocatedFileStatus> iter = fs.listFiles(relative, true);
+      while (iter.hasNext()) {
+        retVal.add(iter.next());
+      }
+      System.out.println("retVal = " + retVal);
+    } finally {
+      cluster.shutdown();
+    }
+  }
 }