PDFBOX-6097: avoid StackOverflow as proposed by Tilman

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1929678 13f79535-47bb-0310-9956-ffa450edef68

Author: lehmi

pdfbox/src/main/java/org/apache/pdfbox/cos/COSDictionary.java

@@ -51,6 +51,8 @@ public class COSDictionary extends COSBase implements COSUpdateInfo
 
     private static final String PATH_SEPARATOR = "/";
 
+    private static final List<COSName> PARENT_KEYS = Arrays.asList(COSName.PARENT, COSName.P);
+
     /**
      * The name-value pairs of this dictionary. The pairs are kept in the order they were added to the dictionary.
      */
@@ -1457,7 +1459,7 @@ public void getIndirectObjectKeys(Collection<COSObjectKey> indirectObjects)
             COSBase cosBase = entry.getValue();
             COSObjectKey cosBaseKey = cosBase != null ? cosBase.getKey() : null;
             // avoid endless recursions
-            if (COSName.PARENT.equals(entry.getKey())
+            if (PARENT_KEYS.contains(entry.getKey())
                     || (cosBaseKey != null && indirectObjects.contains(cosBaseKey)))
             {
                 continue;

pdfbox/src/test/java/org/apache/pdfbox/pdmodel/TestPDPage.java

@@ -0,0 +1,62 @@
+/*
+ * 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.
+ */
+package org.apache.pdfbox.pdmodel;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;
+import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
+import org.apache.pdfbox.pdmodel.interactive.form.PDTextField;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case introduced with PDFBOX-6097
+ * 
+ */
+class TestPDPage
+{
+    @Test
+    void testAddingPageAfterCreatingAnnotation() throws IOException
+    {
+        try (PDDocument document = new PDDocument())
+        {
+            PDPage page = new PDPage(PDRectangle.A4);
+            // Create AcroForm
+            PDAcroForm acroForm = new PDAcroForm(document);
+            document.getDocumentCatalog().setAcroForm(acroForm);
+
+            // Create a single text field
+            PDTextField textField = new PDTextField(acroForm);
+            textField.setPartialName("testField");
+            PDAnnotationWidget widget = textField.getWidgets().get(0);
+            widget.setRectangle(new PDRectangle(100, 700, 200, 20));
+            widget.setPage(page);
+            page.getAnnotations().add(widget);
+            acroForm.getFields().add(textField);
+
+            // Adding page AFTER creating form fields causes a StackOverflowError
+            document.addPage(page);
+
+            document.save(new ByteArrayOutputStream());
+            document.close();
+        }
+    }
+
+}