Add tests demonstrating problems with annotation relationship incorrectly transferred during copying

If annotations refer to other annotations with Popup or IRT keys,
this relationship is not correctly transferred at the moment and the
result is annotation on one page referring to an annotation on
another page, which for IRT key for example is forbidden by the
specification

DEVSIX-3585

Author: Snipx

kernel/src/main/java/com/itextpdf/kernel/pdf/annot/PdfAnnotation.java

@@ -63,6 +63,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.PdfString;
 import com.itextpdf.kernel.pdf.filespec.PdfFileSpec;
 import com.itextpdf.kernel.pdf.layer.IPdfOCG;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -916,7 +917,7 @@ public PdfAnnotation setTitle(PdfString title) {
      * title bar of the annotation’s pop-up window when open and active. For movie annotation Movie actions
      * (ISO-320001 12.6.4.9, "Movie Actions") may use this title to reference the movie annotation.
      *
-     * @return {@link PdfString} which value is an annotation title or null if it isn't specifed.
+     * @return {@link PdfString} which value is an annotation title or null if it isn't specified.
      */
     public PdfString getTitle() {
         return getPdfObject().getAsString(PdfName.T);

kernel/src/test/java/com/itextpdf/kernel/pdf/copy/PdfAnnotationCopyingTest.java

@@ -0,0 +1,147 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2019 iText Group NV
+    Authors: iText Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.itextpdf.kernel.pdf.copy;
+
+import com.itextpdf.io.util.MessageFormatUtil;
+import com.itextpdf.kernel.pdf.PdfDictionary;
+import com.itextpdf.kernel.pdf.PdfDocument;
+import com.itextpdf.kernel.pdf.PdfPage;
+import com.itextpdf.kernel.pdf.PdfReader;
+import com.itextpdf.kernel.pdf.PdfWriter;
+import com.itextpdf.kernel.pdf.annot.PdfAnnotation;
+import com.itextpdf.kernel.pdf.annot.PdfMarkupAnnotation;
+import com.itextpdf.kernel.pdf.annot.PdfPopupAnnotation;
+import com.itextpdf.test.ExtendedITextTest;
+import com.itextpdf.test.annotations.type.IntegrationTest;
+
+import java.io.IOException;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.rules.ExpectedException;
+
+@Category(IntegrationTest.class)
+public class PdfAnnotationCopyingTest extends ExtendedITextTest {
+
+    public static final String destinationFolder = "./target/test/com/itextpdf/kernel/pdf/PdfAnnotationCopyingTest/";
+    public static final String sourceFolder = "./src/test/resources/com/itextpdf/kernel/pdf/PdfAnnotationCopyingTest/";
+
+    @Rule
+    public ExpectedException junitExpectedException = ExpectedException.none();
+
+    @BeforeClass
+    public static void beforeClass() {
+        createOrClearDestinationFolder(destinationFolder);
+    }
+
+    @Test
+    // TODO remove expected exception and thus enable assertions when DEVSIX-3585 is implemented
+    public void testCopyingPageWithAnnotationContainingPopupKey() throws IOException {
+        junitExpectedException.expect(AssertionError.class);
+
+        String inFilePath = sourceFolder + "annotation-with-popup.pdf";
+        String outFilePath = destinationFolder + "copy-annotation-with-popup.pdf";
+        PdfDocument originalDocument = new PdfDocument(new PdfReader(inFilePath));
+        PdfDocument outDocument = new PdfDocument(new PdfWriter(outFilePath));
+
+        originalDocument.copyPagesTo(1, 1, outDocument);
+        // During the second copy call we have to rebuild/preserve all the annotation relationship (Popup in this case),
+        // so that we don't end up with annotation on one page referring to an annotation on another page as its popup
+        // or as its parent
+        originalDocument.copyPagesTo(1, 1, outDocument);
+
+        originalDocument.close();
+        outDocument.close();
+
+        outDocument = new PdfDocument(new PdfReader(outFilePath));
+        for (int pageNum = 1; pageNum <= outDocument.getNumberOfPages(); pageNum++) {
+            PdfPage page = outDocument.getPage(pageNum);
+            Assert.assertEquals(2, page.getAnnotsSize());
+            Assert.assertEquals(2, page.getAnnotations().size());
+            boolean foundMarkupAnnotation = false;
+            for (PdfAnnotation annotation : page.getAnnotations()) {
+                PdfDictionary annotationPageDict = annotation.getPageObject();
+                if (annotationPageDict != null) {
+                    Assert.assertSame(page.getPdfObject(), annotationPageDict);
+                }
+                if (annotation instanceof PdfMarkupAnnotation) {
+                    foundMarkupAnnotation = true;
+                    PdfPopupAnnotation popup = ((PdfMarkupAnnotation) annotation).getPopup();
+                    Assert.assertTrue(MessageFormatUtil.format(
+                            "Popup reference must point to annotation present on the same page (# {0})", pageNum),
+                            page.containsAnnotation(popup));
+                    PdfDictionary parentAnnotation = popup.getParentObject();
+                    Assert.assertSame("Popup annotation parent must point to the annotation that specified it as Popup",
+                            annotation.getPdfObject(), parentAnnotation);
+                }
+            }
+            Assert.assertTrue("Markup annotation expected to be present but not found", foundMarkupAnnotation);
+        }
+        outDocument.close();
+    }
+
+    @Test
+    // TODO remove expected exception and thus enable assertions when DEVSIX-3585 is implemented
+    public void testCopyingPageWithAnnotationContainingIrtKey() throws IOException {
+        junitExpectedException.expect(AssertionError.class);
+
+        String inFilePath = sourceFolder + "annotation-with-irt.pdf";
+        String outFilePath = destinationFolder + "copy-annotation-with-irt.pdf";
+        PdfDocument originalDocument = new PdfDocument(new PdfReader(inFilePath));
+        PdfDocument outDocument = new PdfDocument(new PdfWriter(outFilePath));
+
+        originalDocument.copyPagesTo(1, 1, outDocument);
+        // During the second copy call we have to rebuild/preserve all the annotation relationship (IRT in this case),
+        // so that we don't end up with annotation on one page referring to an annotation on another page as its IRT
+        // or as its parent
+        originalDocument.copyPagesTo(1, 1, outDocument);
+
+        originalDocument.close();
+        outDocument.close();
+
+        outDocument = new PdfDocument(new PdfReader(outFilePath));
+        for (int pageNum = 1; pageNum <= outDocument.getNumberOfPages(); pageNum++) {
+            PdfPage page = outDocument.getPage(pageNum);
+            Assert.assertEquals(4, page.getAnnotsSize());
+            Assert.assertEquals(4, page.getAnnotations().size());
+            boolean foundMarkupAnnotation = false;
+            for (PdfAnnotation annotation : page.getAnnotations()) {
+                PdfDictionary annotationPageDict = annotation.getPageObject();
+                if (annotationPageDict != null) {
+                    Assert.assertSame(page.getPdfObject(), annotationPageDict);
+                }
+                if (annotation instanceof PdfMarkupAnnotation) {
+                    foundMarkupAnnotation = true;
+                    PdfDictionary inReplyTo = ((PdfMarkupAnnotation) annotation).getInReplyToObject();
+                    Assert.assertTrue("IRT reference must point to annotation present on the same page",
+                            page.containsAnnotation(PdfAnnotation.makeAnnotation(inReplyTo)));
+                }
+            }
+            Assert.assertTrue("Markup annotation expected to be present but not found", foundMarkupAnnotation);
+        }
+        outDocument.close();
+    }
+
+}