<measure> blocks without notes

[lemzwerg]

I have a score (created by Capella and converted to MusicXML with its CapToMusic.py script version 2.5 some years ago) that contains measures like the following.

<measure number="47">
  <attributes>
    <time symbol="common">
      <beats>4</beats>
      <beat-type>4</beat-type>
    </time>
  </attributes>
</measure>

This is fully valid MusicXML but semantically invalid AFAICS (so it might be a candidate for issue #621). Looking at the original PDF, the intended output seems to me purely visual, namely to create a time signature after a bar line at the end of a staff:

I've loaded the original .mxl file into MuseScore and Finale, and both programs create a measure with a rest in it, i.e., they are trying to 'fix' the input, and which actually worsens the result (musicxml2ly does the same, BTW 🙂).

I wonder whether there are valid use cases for <measure> elements that don't contain <note>. Otherwise the <measure> specification could change from 'zero or more' to 'at least one' for <note>.

[lemzwerg]

Sadly, no replies. Shall I open an issue for this?

[infojunkie]

The spec is clear that note and all other sub-elements are optional in measure. I would suggest to interpret an empty measure as one that does not advance the music / time / position cursor.

[lemzwerg]

This might be a viable interpretation, yes. However, at least MuseScore and Finale (and musicxml2ly) disagree, as described above...