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

@@ -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:
 --------------
 

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++];

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>