On a certain document, which i can prov

[Reissner]

On a certain document, which i can provide, the following warnings show up:

Dec 12, 2025 2:46:10 PM org.verapdf.parser.COSParser getDictionary
WARNING: Dictionary/Stream contains duplicated key /Group(object key = 6896 0 obj, offset = 545526)
Dec 12, 2025 2:46:10 PM org.verapdf.parser.COSParser getDictionary
WARNING: Dictionary/Stream contains duplicated key /Group(object key = 6288 0 obj, offset = 501131)

Nevertheless, the tests all pass.

[bdoubrov]

@Reissner duplicated keys by itself may or may not be a problem, and this is not even well-defined in the core PDF specification. So, we give it as a warning, but this is not a part of PDF/A compliance requirements.

If you can provide your document, we'll give you more details.

[mkl-public]

duplicated keys by itself may or may not be a problem

Well, they definitively are a problem. The PDF specification requires

Multiple entries in the same dictionary shall not have the same key.

Thus, duplicated keys are invalid in PDF.

(Of course, depending on the document in question, it may not matter which entry is used by a processor - e.g. if they have the same value - but that does not make that construct valid.)

[bdoubrov]

@mkl-public you are right, thanks for the clarification: I somehow missed this statement in the PDF specs. Yet, this is a syntax error of PDF specification, not PDF/A. This is why veraPDF reports it only in the logs.

This question: which base PDF requirements are relevant for PDF/A and should be reported as PDF/A errors as well, is a long-standing discussion with no definitive recommendations at the moment.

[mkl-public]

This question: which base PDF requirements are relevant for PDF/A and should be reported as PDF/A errors as well, is a long-standing discussion with no definitive recommendations at the moment.

Well, strictly speaking all PDF requirements are relevant. E.g. ISO 19005-3 requires:

Conforming PDF/A-3 files shall adhere to all requirements of ISO 32000-1 as modified by this part of ISO 19005.

Consequentially, nearly every PDF requirement implicitly also is a PDF/A requirement.

Of course, though, it's not realistic to expect that PDF/A validators do a full-fledged PDF validation.

I think a good approach would be if the PDF/A validators that don't also do a complete check of the PDF requirements, i.e. all PDF/A validators ;) , report positive validation results as "This file is a valid PDF/A-xy given that it is a valid PDF" or similarly.

[petervwyatt]

This particular error is also more important than some others, since if the duplicated key must be additionally validated (i.e., it has a PDF/A-specific requirement), the answer may vary depending on which key is used!