From 75103dc925dc8db6c65e2281c96998c965c5e3f9 Mon Sep 17 00:00:00 2001
From: Hemanth Yamijala <yhemanth@apache.org>
Date: Tue, 1 Sep 2009 15:24:56 +0000
Subject: [PATCH] HADOOP-6227. Fix Configuration to allow final parameters to
 be set to null and prevent them from being overridden. Contributed by
 Amareshwari Sriramadasu.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@810097 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  4 ++++
 .../org/apache/hadoop/conf/Configuration.java | 23 +++++++++++--------
 .../apache/hadoop/conf/TestConfiguration.java | 23 ++++++++++++++++++-
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 3a206a5fdf..f9056b98f5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -951,6 +951,10 @@ Trunk (unreleased changes)
     HADOOP-6215. fix GenericOptionParser to deal with -D with '=' in the 
     value. (Amar Kamat via sharad)
 
+    HADOOP-6227. Fix Configuration to allow final parameters to be set to null
+    and prevent them from being overridden.
+    (Amareshwari Sriramadasu via yhemanth)
+
 Release 0.20.1 - Unreleased
 
   INCOMPATIBLE CHANGES
diff --git a/src/java/org/apache/hadoop/conf/Configuration.java b/src/java/org/apache/hadoop/conf/Configuration.java
index c53d33a299..edf0f15afe 100644
--- a/src/java/org/apache/hadoop/conf/Configuration.java
+++ b/src/java/org/apache/hadoop/conf/Configuration.java
@@ -1286,17 +1286,20 @@ private void loadResource(Properties properties, Object name, boolean quiet) {
         }
         
         // Ignore this parameter if it has already been marked as 'final'
-        if (attr != null && value != null) {
-          if (!finalParameters.contains(attr)) {
-            properties.setProperty(attr, value);
-            if (storeResource) {
-              updatingResource.put(attr, name.toString());
-            }
-            if (finalParameter)
-              finalParameters.add(attr);
-          } else {
-            LOG.warn(name+":a attempt to override final parameter: "+attr
+        if (attr != null) {
+          if (value != null) {
+            if (!finalParameters.contains(attr)) {
+              properties.setProperty(attr, value);
+              if (storeResource) {
+                updatingResource.put(attr, name.toString());
+              }
+            } else {
+              LOG.warn(name+":a attempt to override final parameter: "+attr
                      +";  Ignoring.");
+            }
+          }
+          if (finalParameter) {
+            finalParameters.add(attr);
           }
         }
       }
diff --git a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
index 12999c3a55..c35caa1b6a 100644
--- a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
+++ b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
@@ -100,7 +100,28 @@ public void testVariableSubstitution() throws IOException {
     assertTrue(conf.getInt("intvar", -1) == 42);
     assertTrue(conf.getInt("my.int", -1) == 42);
   }
-    
+
+  public void testFinalParam() throws IOException {
+    out=new BufferedWriter(new FileWriter(CONFIG));
+    startConfig();
+    declareProperty("my.var", "", "", true);
+    endConfig();
+    Path fileResource = new Path(CONFIG);
+    Configuration conf1 = new Configuration();
+    conf1.addResource(fileResource);
+    assertNull("my var is not null", conf1.get("my.var"));
+	
+    out=new BufferedWriter(new FileWriter(CONFIG2));
+    startConfig();
+    declareProperty("my.var", "myval", "myval", false);
+    endConfig();
+    fileResource = new Path(CONFIG2);
+
+    Configuration conf2 = new Configuration(conf1);
+    conf2.addResource(fileResource);
+    assertNull("my var is not final", conf2.get("my.var"));
+  }
+
   public static void assertEq(Object a, Object b) {
     System.out.println("assertEq: " + a + ", " + b);
     assertEquals(a, b);