From b8c35567eee957064ae29052eae63ee1b4f9c7aa Mon Sep 17 00:00:00 2001
From: Stefan Bodewig <bodewig@apache.org>
Date: Mon, 13 Aug 2012 05:45:10 +0000
Subject: [PATCH] NPE in ExpandProperties when input is empty.  PR 53626

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1372266 13f79535-47bb-0310-9956-ffa450edef68
---
 WHATSNEW                                          |  4 ++++
 .../tools/ant/filters/ExpandProperties.java       | 10 +++++++---
 .../antunit/filters/expandproperties-test.xml     | 15 +++++++++++++++
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/WHATSNEW b/WHATSNEW
index 03a1022a4..eded0c2bf 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -50,6 +50,10 @@ Fixed bugs:
    handledirsep="true".
    Bugzilla Report 53399.
 
+ * <expandproperties> filter caused a NullPointerExcpetion when input
+   was empty.
+   Bugzilla Report 53626.
+
 Other changes:
 --------------
 
diff --git a/src/main/org/apache/tools/ant/filters/ExpandProperties.java b/src/main/org/apache/tools/ant/filters/ExpandProperties.java
index 0ca288edb..524a799b1 100644
--- a/src/main/org/apache/tools/ant/filters/ExpandProperties.java
+++ b/src/main/org/apache/tools/ant/filters/ExpandProperties.java
@@ -107,9 +107,13 @@ public final class ExpandProperties
                         }
                     };
                 }
-                buffer = new ParseProperties(project, PropertyHelper.getPropertyHelper(project)
-                        .getExpanders(), getProperty).parseProperties(data).toString()
-                        .toCharArray();
+                Object expanded = new ParseProperties(project, PropertyHelper
+                                                      .getPropertyHelper(project)
+                                                      .getExpanders(),
+                                                      getProperty)
+                    .parseProperties(data);
+                buffer = expanded == null ? new char[0]
+                    : expanded.toString().toCharArray();
             }
             if (index < buffer.length) {
                 return buffer[index++];
diff --git a/src/tests/antunit/filters/expandproperties-test.xml b/src/tests/antunit/filters/expandproperties-test.xml
index 44195fe3c..5dff8320c 100644
--- a/src/tests/antunit/filters/expandproperties-test.xml
+++ b/src/tests/antunit/filters/expandproperties-test.xml
@@ -74,4 +74,19 @@
     </au:assertTrue>
   </target>
 
+  <target name="testEmptyResource"
+          description="https://issues.apache.org/bugzilla/show_bug.cgi?id=53626">
+    <au:assertTrue>
+      <resourcesmatch>
+        <string value="" />
+        <concat>
+          <string value="" />
+          <filterchain>
+            <expandproperties />
+          </filterchain>
+        </concat>
+      </resourcesmatch>
+    </au:assertTrue>
+  </target>
+
 </project>