FOP-3072: Empty link url gives NPE

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1900951 13f79535-47bb-0310-9956-ffa450edef68

fop-core/src/main/java/org/apache/fop/render/intermediate/IFRenderer.java

@@ -980,10 +980,12 @@ public class IFRenderer extends AbstractPathOrientedRenderer {
             this.deferredLinks.add(link);
         } else if (ip instanceof BasicLinkArea) {
             BasicLinkArea linkArea = (BasicLinkArea) ip;
-            String id = linkArea.getResolver().getIDRefs()[0];
-            action = getGoToActionForID(id, -1);
-            Link link = new Link(action, ipRect);
-            this.deferredLinks.add(link);
+            if (linkArea.getResolver() != null) {
+                String id = linkArea.getResolver().getIDRefs()[0];
+                action = getGoToActionForID(id, -1);
+                Link link = new Link(action, ipRect);
+                this.deferredLinks.add(link);
+            }
         }
     }
 

fop/test/intermediate/basic-link_empty.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+<!-- $Id$ -->
+<testcase>
+  <info>
+    <p>
+      This test checks a empty fo:basic-link
+    </p>
+  </info>
+  <fo>
+    <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
+      <fo:layout-master-set>
+        <fo:simple-page-master master-name="page" page-height="420pt" page-width="320pt" margin="10pt">
+          <fo:region-body/>
+        </fo:simple-page-master>
+      </fo:layout-master-set>
+      <fo:page-sequence master-reference="page">
+        <fo:flow flow-name="xsl-region-body">
+          <fo:block>
+            <fo:basic-link external-destination="url('')">a</fo:basic-link>
+          </fo:block>
+        </fo:flow>
+      </fo:page-sequence>
+    </fo:root>
+  </fo>
+  <if-checks xmlns:if="http://xmlgraphics.apache.org/fop/intermediate">
+    <eval expected="a" xpath="//if:text"/>
+  </if-checks>
+</testcase>