Fix edge condition with extension list calculation

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@113277 13f79535-47bb-0310-9956-ffa450edef68

jar/plugin.jelly

@@ -58,13 +58,17 @@
         <j:if test="${!empty(mainclass)}">
             <ant:attribute name="Main-Class" value="${mainclass}"/>
         </j:if>
-        <j:set var="extensionList" value=""/>
-        <j:forEach var="artifact" items="${pom.artifacts}">
-          <j:set var="dep" value="${artifact.dependency}"/>
-	      <j:set var="extensionList" value="${extensionList},${dep.artifactId}"/>
-        </j:forEach>
-        <j:set var="extensionList" value="${extensionList.substring(1)}"/>
-        <ant:attribute name="Extension-List" value="${extensionList}"/>
+        
+        <j:if test="${pom.getArtifacts().size() > 0}">
+          <j:set var="extensionList" value=""/>
+          <j:forEach var="artifact" items="${pom.artifacts}">
+            <j:set var="dep" value="${artifact.dependency}"/>
+	        <j:set var="extensionList" value="${extensionList},${dep.artifactId}"/>
+          </j:forEach>
+        
+          <j:set var="extensionList" value="${extensionList.substring(1)}"/>
+          <ant:attribute name="Extension-List" value="${extensionList}"/>
+        </j:if>
         
         <j:forEach var="artifact" items="${pom.artifacts}">
           <j:set var="dep" value="${artifact.dependency}"/>