From a2d560310631c85b9996f895e3a163c4f35e538e Mon Sep 17 00:00:00 2001
From: Robert Joseph Evans <bobby@apache.org>
Date: Tue, 24 Jul 2012 19:00:50 +0000
Subject: [PATCH] HADOOP-8606. FileSystem.get may return the wrong filesystem
 (Daryn Sharp via bobby)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1365224 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop-common/CHANGES.txt                 |  3 +
 .../java/org/apache/hadoop/fs/FileSystem.java |  4 +-
 .../hadoop/fs/TestFileSystemCaching.java      | 61 ++++++++++++++++++-
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index d4c4e6a07cb..ebd833bdb66 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -838,6 +838,9 @@ Release 0.23.3 - UNRELEASED
     HADOOP-8599. Non empty response from FileSystem.getFileBlockLocations when
     asking for data beyond the end of file. (Andrey Klochkov via todd)
 
+    HADOOP-8606. FileSystem.get may return the wrong filesystem (Daryn Sharp
+    via bobby)
+
 Release 0.23.2 - UNRELEASED 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
index 62b48cf7467..f65d12c711c 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
@@ -280,11 +280,11 @@ public abstract class FileSystem extends Configured implements Closeable {
     String scheme = uri.getScheme();
     String authority = uri.getAuthority();
 
-    if (scheme == null) {                       // no scheme: use default FS
+    if (scheme == null && authority == null) {     // use default FS
       return get(conf);
     }
 
-    if (authority == null) {                       // no authority
+    if (scheme != null && authority == null) {     // no authority
       URI defaultUri = getDefaultUri(conf);
       if (scheme.equals(defaultUri.getScheme())    // if scheme matches default
           && defaultUri.getAuthority() != null) {  // & default has authority
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemCaching.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemCaching.java
index 1e176a0a12f..910139b56ec 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemCaching.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemCaching.java
@@ -34,8 +34,8 @@ import org.junit.Test;
 import java.security.PrivilegedExceptionAction;
 import java.util.concurrent.Semaphore;
 
+import static org.junit.Assert.*;
 import static org.mockito.Mockito.mock;
-import static junit.framework.Assert.assertTrue;
 
 
 public class TestFileSystemCaching {
@@ -49,6 +49,65 @@ public class TestFileSystemCaching {
     assertSame(fs1, fs2);
   }
 
+  static class DefaultFs extends LocalFileSystem {
+    URI uri;
+    @Override
+    public void initialize(URI uri, Configuration conf) {
+      this.uri = uri;
+    }
+    @Override
+    public URI getUri() {
+      return uri;
+    }
+  }
+  
+  @Test
+  public void testDefaultFsUris() throws Exception {
+    final Configuration conf = new Configuration();
+    conf.set("fs.defaultfs.impl", DefaultFs.class.getName());
+    final URI defaultUri = URI.create("defaultfs://host");
+    FileSystem.setDefaultUri(conf, defaultUri);
+    FileSystem fs = null;
+    
+    // sanity check default fs
+    final FileSystem defaultFs = FileSystem.get(conf);
+    assertEquals(defaultUri, defaultFs.getUri());
+    
+    // has scheme, no auth
+    fs = FileSystem.get(URI.create("defaultfs:/"), conf);
+    assertSame(defaultFs, fs);
+    fs = FileSystem.get(URI.create("defaultfs:///"), conf);
+    assertSame(defaultFs, fs);
+    
+    // has scheme, same auth
+    fs = FileSystem.get(URI.create("defaultfs://host"), conf);
+    assertSame(defaultFs, fs);
+    
+    // has scheme, different auth
+    fs = FileSystem.get(URI.create("defaultfs://host2"), conf);
+    assertNotSame(defaultFs, fs);
+    
+    // no scheme, no auth
+    fs = FileSystem.get(URI.create("/"), conf);
+    assertSame(defaultFs, fs);
+    
+    // no scheme, same auth
+    try {
+      fs = FileSystem.get(URI.create("//host"), conf);
+      fail("got fs with auth but no scheme");
+    } catch (Exception e) {
+      assertEquals("No FileSystem for scheme: null", e.getMessage());
+    }
+    
+    // no scheme, different auth
+    try {
+      fs = FileSystem.get(URI.create("//host2"), conf);
+      fail("got fs with auth but no scheme");
+    } catch (Exception e) {
+      assertEquals("No FileSystem for scheme: null", e.getMessage());
+    }
+  }
+  
   public static class InitializeForeverFileSystem extends LocalFileSystem {
     final static Semaphore sem = new Semaphore(0);
     public void initialize(URI uri, Configuration conf) throws IOException {