Multiple [BT-3] InvoiceReferencedDocument entries not possible

[bee-eater]

Hi,

first of all thanks for you awesome work!

I highly appreciate this library, as I can implement my own ZUGFeRD solution for my invoicing!

One thing I stumbled uppon:
If you have a few partial invoices and end up with a final one, you should provide references to the partial invoices in [BG-3] InvoiceReferencedDocument which is represendted by document.trade.settlement.invoice_referenced_document correct?

According to the spec, multiple references (0...unbounded) should be possible here, so invoice_referenced_document should be a MultiField, right?

I tried to change it and it seems to work fine (also the xml looks good so far) with one problem: TypeCode ends up giving me a validation issue as soon as I add it:

  File "d:\Dev\inveasy\backend\.venv\Lib\site-packages\drafthorse\models\document.py", line 119, in serialize
    xml = super().serialize(schema)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "d:\Dev\inveasy\backend\.venv\Lib\site-packages\drafthorse\models\elements.py", line 80, in serialize
    def __setattr__(self, key, value):
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "d:\Dev\inveasy\backend\.venv\Lib\site-packages\drafthorse\utils.py", line 21, in validate_xml
    xml_root = etree.fromstring(xmlout, parser)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "src\\lxml\\etree.pyx", line 3307, in lxml.etree.fromstring
  File "src\\lxml\\parser.pxi", line 1995, in lxml.etree._parseMemoryDocument
  File "src\\lxml\\parser.pxi", line 1882, in lxml.etree._parseDoc
  File "src\\lxml\\parser.pxi", line 1164, in lxml.etree._BaseParser._parseDoc
  File "src\\lxml\\parser.pxi", line 633, in lxml.etree._ParserContext._handleParseResultDoc
  File "src\\lxml\\parser.pxi", line 743, in lxml.etree._handleParseResult
  File "src\\lxml\\parser.pxi", line 672, in lxml.etree._raiseParseError
  File "<string>", line 0
lxml.etree.XMLSyntaxError: Element '{urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100}TypeCode': This element is not expected.

I couldn't really figure out why, since the schema for ReferencedDocumentType contains the TypeCode as child, and the created xml also looked fine to me when I debugged it. Since it's not indented, line 0 also doesn't really help.

It's not critical for me, but I still wanted to provide the feedback. Thanks again!

Best regards!

[raphaelm]

I think you can have multiple BG-3 but not multiple BT-25 in one BG-3?

[bee-eater]

Yes, but multiple BT-3 is not working with the current drafthorse version, is it? It's a Field, not a MultiField?!