Hi PdfBox Team,
we have a problem with a customer document.
Download:
[pdf-Symbol]
form_with_checkbox.pdf<https://signotecgmbh-my.sharepoint.com/:b:/g/personal/markus_mensinger_signotec_de/IQAWsk5J73_SQqx9_zcLNG2xAVUGtCVXhIGE8jW_vpRMV1c?e=fhAPAv>
Link valid until 08.05.
Here is a bug report generated with Claude Sonnet.
Component: PDFBox - Interactive Forms (AcroForm)
Affects Version: 3.0.7
Type: Bug
SUMMARY
When a checkbox field in an AcroForm PDF contains an empty /Opt array (/Opt [])
in its field dictionary, calling PDCheckBox.setValue("Yes") throws an
IllegalArgumentException, even though "Yes" is a perfectly valid export value
defined by the field's appearance states.
The same field can be checked and unchecked without any error using Adobe
Acrobat
products (Acrobat Reader, Acrobat Pro), which treat the empty /Opt array as if
it
were absent. This confirms that the PDF is valid and the issue is specific to
PDFBox's validation logic.
ERROR MESSAGE
java.lang.IllegalArgumentException: value 'Yes' is not a valid option
for the field Check_Info_Post_andere, valid values are: [] and Off
ROOT CAUSE
The validation in PDCheckBox.setValue() checks the /Opt array when it is
present.
If the array exists but is empty, all non-"Off" values are rejected - including
the
export value "Yes" that is defined in the field's appearance dictionary (/AP).
The empty /Opt array should either be ignored or treated as absent - which is
exactly what Adobe Acrobat does.
STEPS TO REPRODUCE
import org.apache.pdfbox.Loader;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.interactive.form.PDCheckBox;
import org.apache.pdfbox.pdmodel.interactive.form.PDField;
import java.io.File;
public class CheckBoxBugDemo {
public static void main(String[] args) {
try (PDDocument doc = Loader.loadPDF(new
File("form_with_checkbox.pdf"))) {
PDField field = doc.getDocumentCatalog()
.getAcroForm()
.getField("Check_Info_Post_andere");
System.out.println("Field type : " + field.getFieldType());
System.out.println("/Opt entry : " +
field.getCOSObject().getItem(COSName.OPT)); // prints:
COSArray{}
// Workaround: manually remove the empty /Opt array before setting
value
COSArray opt = (COSArray)
field.getCOSObject().getDictionaryObject(COSName.OPT);
if (opt != null && opt.size() == 0) {
field.getCOSObject().removeItem(COSName.OPT);
System.out.println("/Opt removed (was empty)");
}
// Without the workaround above, this line throws
IllegalArgumentException:
// "value 'Yes' is not a valid option ... valid values are: [] and
Off"
((PDCheckBox) field).setValue("Yes");
System.out.println("Value set successfully: " + ((PDCheckBox)
field).getValue());
} catch (Exception e) {
e.printStackTrace();
}
}
}
EXPECTED BEHAVIOR
An empty /Opt array should be treated the same as a missing /Opt entry. The
value
"Yes" (or any export value present in the field's appearance states) should be
accepted. This is consistent with how Adobe Acrobat Reader and Acrobat Pro
handle
this case.
ACTUAL BEHAVIOR
PDCheckBox.setValue("Yes") throws IllegalArgumentException because the empty
/Opt
array causes the valid-options check to return an empty list, which excludes
"Yes".
WORKAROUND
Remove the empty /Opt entry from the field dictionary before calling setValue():
COSArray opt = (COSArray)
field.getCOSObject().getDictionaryObject(COSName.OPT);
if (opt != null && opt.size() == 0) {
field.getCOSObject().removeItem(COSName.OPT);
}
((PDCheckBox) field).setValue("Yes");
SUGGESTED FIX
In the PDFBox source, the method that validates allowed values for a checkbox
should
skip or ignore the /Opt array when it is present but empty (size() == 0),
bringing
the behavior in line with Adobe Acrobat.
Kind regards
Markus
