Handle annotations missing a subtype

DEVSIX-4742

Author: e-zhavoronok

forms/src/main/java/com/itextpdf/forms/PdfPageFormCopier.java

@@ -103,6 +103,11 @@ public void copy(PdfPage fromPage, PdfPage toPage) {
 
         try {
             for (PdfAnnotation annot : annots) {
+                if (annot.getSubtype() == null) {
+                    logger.warn(MessageFormatUtil.format(FormsLogMessageConstants.ANNOTATION_WITHOUT_SUBTYPE_NOT_COPIED,
+                            annot.getPdfObject().getIndirectReference()));
+                    continue;
+                }
                 if (!annot.getSubtype().equals(PdfName.Widget)) {
                     continue;
                 }

forms/src/main/java/com/itextpdf/forms/logs/FormsLogMessageConstants.java

@@ -30,7 +30,7 @@ public final class FormsLogMessageConstants {
     public static final String ACROFORM_NOT_SUPPORTED_FOR_SELECT =
             "AcroForm fields creation for select fields (ComboBoxField and ListBoxField) is not supported. They will "
                     + "be flattened instead.";
-    
+
     public static final String ANNOTATION_IN_ACROFORM_DICTIONARY = "Annotation is noticed directly in fields array "
             + "of AcroForm dictionary. It violates pdf specification.";
 
@@ -86,6 +86,9 @@ public final class FormsLogMessageConstants {
     public static final String DUPLICATE_EXPORT_VALUE = "More than one option with the same value. This is an invalid"
             + " state.";
 
+    public static final String ANNOTATION_WITHOUT_SUBTYPE_NOT_COPIED = "Encountered an annotation without "
+            + "a Subtype property: {0}. If there is a corresponding Acroform field, it will not be copied";
+
     private FormsLogMessageConstants() {
     }
 }

forms/src/test/java/com/itextpdf/forms/PdfFormCopyTest.java

@@ -23,6 +23,7 @@ This file is part of the iText (R) project.
 package com.itextpdf.forms;
 
 import com.itextpdf.forms.fields.PdfFormCreator;
+import com.itextpdf.forms.logs.FormsLogMessageConstants;
 import com.itextpdf.io.logs.IoLogMessageConstant;
 import com.itextpdf.io.source.ByteArrayOutputStream;
 import com.itextpdf.kernel.pdf.PdfDocument;
@@ -699,4 +700,19 @@ public void widgetContainsNoTEntryTest() throws IOException, InterruptedExceptio
         resultPdfDocument.close();
         Assertions.assertNull(new CompareTool().compareByContent(destFileName, cmpFileName, destinationFolder, "diff_"));
     }
+
+    @Test
+    @LogMessages(messages = {
+            @LogMessage(messageTemplate = FormsLogMessageConstants.ANNOTATION_WITHOUT_SUBTYPE_NOT_COPIED, count = 1)
+    })
+    public void copyWithNoSubtypeInAnnotationTest() throws Exception {
+        String sourceFileName = sourceFolder + "copyWithNoSubtypeInAnnotationTest.pdf";
+        String destFileName = destinationFolder + "copyWithNoSubtypeInAnnotationTest.pdf";
+        String cmpFileName = sourceFolder + "cmp_copyWithNoSubtypeInAnnotationTest.pdf";
+        PdfDocument sourcePdfDocument = new PdfDocument(new PdfReader(sourceFileName));
+        PdfDocument resultPdfDocument = new PdfDocument(new PdfWriter(destFileName));
+        sourcePdfDocument.copyPagesTo(1, sourcePdfDocument.getNumberOfPages(), resultPdfDocument, new PdfPageFormCopier());
+        resultPdfDocument.close();
+        Assertions.assertNull(new CompareTool().compareByContent(destFileName, cmpFileName, destinationFolder, "diff_"));
+    }
 }