#38056: NPE when using presetdef under obscure circumstances.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@359329 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -67,7 +67,8 @@ Changes that could break older environments:
 
 Fixed bugs:
 -----------
-* Some potential NullPointerExceptions, Bugzilla Report 37765
+
+* Some potential NullPointerExceptions, Bugzilla Reports 37765 and 38056
 
 * Problem when adding multiple filter files, Bugzilla Report 37341
 

src/etc/testcases/taskdefs/presetdef.xml

@@ -118,4 +118,13 @@
     </javac>
   </target>
 
+    <target name="presetdef-with-nested-element-twice">
+        <copy todir=".">
+            <fileset dir="." includes="nonexistent"/>
+        </copy>
+        <presetdef name="copy">
+            <copy verbose="true"/>
+        </presetdef>
+    </target>
+
 </project>

src/main/org/apache/tools/ant/UnknownElement.java

@@ -41,7 +41,7 @@ public class UnknownElement extends Task {
     /**
      * Holds the namespace of the element.
      */
-    private String namespace;
+    private String namespace = "";
 
     /**
      * Holds the namespace qname of the element.
@@ -111,7 +111,7 @@ public class UnknownElement extends Task {
                 getProject());
             namespace = helper.getCurrentAntlibUri();
         }
-        this.namespace = namespace;
+        this.namespace = namespace == null ? "" : namespace;
     }
 
     /** Return the qname of the XML element associated with this component.

src/testcases/org/apache/tools/ant/taskdefs/PreSetDefTest.java

@@ -80,6 +80,10 @@ public class PreSetDefTest extends BuildFileTest {
             "correct_taskname_badel", "element message", "javac doesn't support the");
     }
     
+    public void testPresetdefWithNestedElementTwice() { // #38056
+        executeTarget("presetdef-with-nested-element-twice");
+        executeTarget("presetdef-with-nested-element-twice");
+    }
     
     /**
      * A test class to check default properties