FOP-3026: Fix NPE with empty table header

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1892815 13f79535-47bb-0310-9956-ffa450edef68

fop-core/src/main/java/org/apache/fop/layoutmgr/table/RowPainter.java

@@ -198,6 +198,9 @@ class RowPainter {
      * in the outer mode
      */
     private void addAreasAndFlushRow(boolean lastInPart, boolean lastOnPage) {
+        if (currentRow == null) {
+            return;
+        }
         if (log.isDebugEnabled()) {
             log.debug("Remembering yoffset for row " + currentRow.getIndex() + ": "
                     + currentRowOffset);

fop/test/layoutengine/standard-testcases/table_empty_header.xml

@@ -0,0 +1,69 @@
+<?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 basic tables.
+    </p>
+  </info>
+  <cfg>
+    <strict-validation>false</strict-validation>
+  </cfg>
+  <fo>
+    <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:fox="http://xmlgraphics.apache.org/fop/extensions">
+      <fo:layout-master-set>
+        <fo:simple-page-master margin-right="1cm" margin-left="1cm" margin-bottom="0.3cm" margin-top="1cm" page-width="21cm" page-height="29.7cm" master-name="all">
+          <fo:region-body margin-left="0cm" margin-bottom="1cm" margin-right="0cm" margin-top="0cm"/>
+        </fo:simple-page-master>
+      </fo:layout-master-set>
+      <fo:page-sequence format="1" id="th_default_sequence1" master-reference="all">
+        <fo:flow flow-name="xsl-region-body">
+          <fo:block>
+            <fo:table table-layout="fixed" width="100%" border-collapse="separate">
+              <fo:table-column column-width="proportional-column-width(100)" column-number="1"/>
+              <fo:table-header/>
+              <fo:table-body>
+                <fo:table-row>
+                  <fo:table-cell>
+                    <fo:block>
+                      <fo:block>D14</fo:block>
+                    </fo:block>
+                  </fo:table-cell>
+                </fo:table-row>
+              </fo:table-body>
+              <fo:table-footer>
+                <fo:table-row>
+                  <fo:table-cell>
+                    <fo:block>
+                      <fo:block>D15</fo:block>
+                    </fo:block>
+                  </fo:table-cell>
+                </fo:table-row>
+              </fo:table-footer>
+            </fo:table>
+          </fo:block>
+        </fo:flow>
+      </fo:page-sequence>
+    </fo:root>
+  </fo>
+  <checks>
+    <eval expected="D14" xpath="//block/block[1]//word"/>
+    <eval expected="D15" xpath="//block/block[2]//word"/>
+  </checks>
+</testcase>