Producer set to Author instead of producing software in document properties

[Vampire]

If you generate a document without author line, the document properties of the generated PDF show:

In English the field is called "PDF Producer" which is more ambiguous in what it could mean than the german "PDF created with" literally translated.

This is imho the correct thing to have in this field,
which is also backed by the example at the end of section 14.3.3 in https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf which shows:

But if you set an author line on the document, that line is used as Producer:

In English where the field is just called "Producer" both values could fit, though it is a bit inconsistent.
But the example in the standard and the localization of Acrobat Reader suggest that the author should not be put there.

[mojavelinux]

Here are the definitions of these fields according to the PDF specification:

• /Creator (Optional) If the document was converted to PDF from another format, the name of the conforming product that created the original document from which it was converted.
• /Producer (Optional) If the document was converted to PDF from another format, the name of the conforming product that converted it to PDF.

It would seem as though the Creator is for whatever product created the AsciiDoc (if relevant) and the Producer is for whatever product generated/produced the PDF (in this case Asciidoctor PDF + Prawn).

I would agree that Producer should be the Asciidoctor PDF credit.

Note that the Producer field can be overridden using the publisher attribute, which was requested/required by one of the users of Asciidoctor PDF long ago. (I think I'll add producer as a fallback just for completeness).

For Creator, I'm not sure. I think perhaps we should default that field to the author, but still allow it to be overridden using the creator attribute.

[mojavelinux]

Here's what I'm thinking. /Producer can be overridden using the producer attribute, but will default to the Asciidoctor PDF credit line. /Creator can be overridden using the publisher attribute, but will default to the author. (Here I'm remapping the publisher attribute to /Creator instead of /Producer per the description in the PDF specification).

(We always have to populate both fields or Prawn will fill them in with the text "Prawn").

[mojavelinux]

/Creator can be overridden using the publisher attribute

I sure wish there was a /Publisher field, but there just isn't (and most PDF readers don't show custom fields). So publisher → /Creator just has to mean what the author wants it to mean. What's important is that now you'll have control over both fields, which is the key focus here in my mind.