HDFS-538. Per the contract elucidated in HADOOP-6201, throw

FileNotFoundException from FileSystem::listStatus rather than returning
null. Contributed by Jakob Homan.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/hdfs/trunk@806746 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -2,6 +2,12 @@ Hadoop HDFS Change Log
 
 Trunk (unreleased changes)
 
+  INCOMPATIBLE CHANGES
+
+    HDFS-538. Per the contract elucidated in HADOOP-6201, throw
+    FileNotFoundException from FileSystem::listStatus rather than returning
+    null. (Jakob Homan via cdouglas)
+
   NEW FEATURES
 
     HDFS-436. Introduce AspectJ framework for HDFS code and tests.

src/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -258,7 +258,9 @@ public class DistributedFileSystem extends FileSystem {
   @Override
   public FileStatus[] listStatus(Path p) throws IOException {
     FileStatus[] infos = dfs.listPaths(getPathName(p));
-    if (infos == null) return null;
+    if (infos == null) 
+      throw new FileNotFoundException("File " + p + " does not exist.");
+    
     FileStatus[] stats = new FileStatus[infos.length];
     for (int i = 0; i < infos.length; i++) {
       stats[i] = makeQualified(infos[i]);

src/test/hdfs-with-mr/org/apache/hadoop/fs/DistributedFSCheck.java

@@ -21,6 +21,7 @@ package org.apache.hadoop.fs;
 import java.io.BufferedReader;
 import java.io.DataInputStream;
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
@@ -132,9 +133,13 @@ public class DistributedFSCheck extends TestCase {
       return;
     }
     
-    FileStatus children[] = fs.listStatus(rootFile);
-    if (children == null)
+    FileStatus [] children = null;
+    try {
+      children = fs.listStatus(rootFile);
+    } catch (FileNotFoundException fnfe ){
       throw new IOException("Could not get listing for " + rootFile);
+    }
+
     for (int i = 0; i < children.length; i++)
       listSubtree(children[i], writer);
   }