[webern]

AI Summary

MusicXML allows an accidental-mark in two places: directly in notations, where it stands above or below the note on its own, and inside ornaments right after an ornament, where it belongs to that ornament (the sharp over a trill that raises its upper note, the accidentals above and below a turn). mx read both as flat MarkType::accidentalMark* marks, losing which ornament an accidental belonged to, and since #462 wrote every one back at the notations level, outside the ornament.

An ornament mark now owns its accidentals. MarkDataChoice gains a new alternative, Kind::ornament, holding OrnamentMarkData:

• OrnamentMarkData::accidentals is the ornament's list of OrnamentAccidental, in order. A trill, a turn of any kind, a shake, a mordent, an inverted mordent, a schleifer and a haydn can hold one. An OrnamentMarkData with no accidentals collapses to none, so a plain trill compares equal however it was built.
• OrnamentAccidental::accidental is the accidental to show (api::Accidental).
• OrnamentAccidental::positionData is where it sits, measured from the ornament rather than from the note, as MusicXML defines it.

The reader fills the list for each ornament from the accidental marks that follow it, and the writer puts each one back inside ornaments right after its ornament. Accidental marks in notations are unchanged.

Defined fallbacks, each with a diagnostic:

• An accidental after a tremolo, an other-ornament or a wavy line has no ornament mark that can hold it (the tremolo and other-ornament already carry TremoloMarkData and OtherMarkData; a wavy line is not a mark). It is read as a standalone accidental mark, as before, with a warning.
• An accidental-mark inside ornaments with the value other has no api::Accidental, so it is left out with an error. It used to become a MarkType::unspecified mark that was never written.
• On write, an entry left at Accidental::none, and an OrnamentMarkData on a mark that cannot hold it (a tremolo, an other-ornament, or a mark that is not an ornament), are left out with an error.

Behaviour change

Reading <trill-mark/><accidental-mark>sharp</accidental-mark> used to give two marks, a trill and an accidentalMarkSharp. It now gives one trill mark whose choice.ornament().accidentals holds the sharp, and writing puts the sharp back inside ornaments after the trill. Code that looked in marks for a trill's accidental must now look in the trill. Accidental marks you author, and ones read from notations, are unchanged and still write at the notations level.

Out of scope

The accidental mark's drawing attributes (parentheses, bracket, size, SMuFL glyph, id, font and color) are still not read or written, for standalone and ornament accidentals alike. They come in the next layer of this stack. The two synthetic accidental-mark fixtures need them, so this change pins no new file.

Testing

• New and updated api tests: trill, turn with two accidentals, two ornaments each with their own accidental, every ornament that can own accidentals, standalone plus ornament accidental on one note, wavy-line start after a trill's accidental, each fallback and its diagnostic, choice accessors, equality and the empty-list collapse
• make api-test: 6768 assertions in 798 test cases pass
• make api-roundtrip: 458 of 458 pinned files pass
• make api-roundtrip-discover: 459 pass, 382 fail, the same pass list as main. lysuite/ly32a_Notations.xml and recsuite/MozaChloSample.xml still fail for unrelated reasons, but every accidental-mark difference in their round-trip diff is gone
• make audit-test passes (19 tests); unity build of target mx passes; make fmt-check passes

References

• Closes the writer drops tuplet position, midi-unpitched and accidental marks #443
• Follows fix: write back tuplet position data, midi-unpitched and accidental marks #462, which wrote accidental marks at the notations level
• Related: expose the id attribute of dynamics, fermata and accidental-mark in mx::api #403 (the accidental-mark id attribute)
• Bottom of a two-layer stack based on main; there is no pull request below it