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https://issues.apache.org/jira/browse/PDFBOX-5714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17799041#comment-17799041
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Tilman Hausherr edited comment on PDFBOX-5714 at 12/20/23 8:10 PM:
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I added the two prints before the first save and they are both "true", so
whatever bad things happen, happen when saving.
writeReference() is when the (wrong) "2 0 R" and "3 0 R" are written. It calls
{{getObjectKey(obj)}} to get the key. For some reason, that one returns "2 0 R"
and "3 0 R" for the problematic objects instead of returning new keys.
Here's some modified code that aborts when the problem happens
{code:java}
private COSObjectKey getObjectKey( COSBase obj )
{
COSBase actual = obj;
if( actual instanceof COSObject )
{
if (reuseObjectNumbers)
{
COSObjectKey key = obj.getKey();
if (key != null)
{
for (Entry<COSBase, COSObjectKey> entry :
objectKeys.entrySet())
{
if (key.equals(entry.getValue()) &&
entry.getKey() != obj && entry.getKey() != ((COSObject) obj).getObject())
{
throw new
RuntimeException("Duplicate object key " + entry.getKey() + " " +
entry.getValue());
}
}
objectKeys.put(obj, key);
return key;
}
}
actual = ((COSObject) obj).getObject();
}
// PDFBOX-4540: because objectKeys is accessible from outside, it is
possible
// that a COSObject obj is already in the objectKeys map.
return objectKeys.computeIfAbsent(actual, k -> new
COSObjectKey(++number, 0));
}
{code}
was (Author: tilman):
I added the two prints before the first save and they are both "true", so
whatever bad things happen, happen when saving.
writeReference() is when the (wrong) "2 0 R" and "3 0 R" are written. It calls
{{getObjectKey(obj)}} to get the key. For some reason, that one returns "2 0 R"
and "3 0 R" for the problematic objects instead of returning new keys.
> PDFBox 3.0 regression: duplicate references in dictionary values
> ----------------------------------------------------------------
>
> Key: PDFBOX-5714
> URL: https://issues.apache.org/jira/browse/PDFBOX-5714
> Project: PDFBox
> Issue Type: Bug
> Components: Writing
> Affects Versions: 3.0.0 PDFBox
> Environment: macOS 14, Java 11
> Reporter: Derek Wickern
> Priority: Major
> Labels: regression
> Attachments: PdfboxAnnotationRegressionTest.java,
> basic-sticky-note.fdf, out-pdfbox2.pdf, out-pdfbox3.pdf, w4.pdf
>
>
> {{basic-sticky-note.fdf}} contains an Acrobat "sticky note", which consists
> of two annotations: text (2 0 obj) and popup (3 0 obj). The annotations
> reference each other. The text annotation's "/Popup 3 0 R" references the
> popup annotation. The popup's "/Parent 2 0 R" references the text annotation.
>
> {code:java}
> 2 0 obj
> <<... /Popup 3 0 R ...>>
> endobj
> 3 0 obj
> <<... /Parent 2 0 R ...>>
> endobj
> {code}
>
> The attached Java program copies those annotations onto {{{}w4.pdf{}}}, saves
> the file, then reads it back to verify the result.
> h3. Expected Behavior
> {{out-pdfbox2.pdf}} is the output using pdfbox 2.0.30. The annotation objects
> are reassigned to some available ID:
>
> {code:java}
> 38 0 obj
> << ... /Popup 39 0 R ... >>
> endobj
> 39 0 obj
> << ... /Parent 38 0 R ...>>
> endobj
> {code}
>
> The program outputs:
> {code:java}
> correct parent? true
> correct popup? true{code}
> h3. Actual Behavior
> {{out-pdfbox3.pdf}} is the output using pdfbox 3.0.0. The objects are
> assigned a new ID but their references are unchanged, so the /Popup and
> /Parent reference some other arbitrary object:
>
> {code:java}
> 3473 0 obj
> << ... /Popup 3 0 R ... >>
> endobj
> 3474 0 obj
> << ... /Parent 2 0 R ...>>
> endobj
> {code}
>
> The program crashes since the dereferenced /Parent is not an annotation:
> {code:java}
> Exception in thread "main" java.lang.ClassCastException: class
> org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationUnknown cannot
> be cast to class
> org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationMarkup
> (org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationUnknown and
> org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationMarkup are in
> unnamed module of loader 'app')
> at
> org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationPopup.getParent(PDAnnotationPopup.java:99)
> at
> PdfboxAnnotationRegressionTest.main(PdfboxAnnotationRegressionTest.java:45)
> {code}
>
>
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