Notes added needs to be in order to be written

[OctoFlareDev]

This can be solved by adding a thing like file.notes.sort(key=lambda note: (note.tick, note.layer)) before writing to file

[Bentroen]

Hi! Thanks for reporting the issue.

We already sort the notes by tick, and then the notes in each tick by layer, prior to writing. The writer uses File's __iter__ method to iterate all ticks and "chords" in order:

pynbs/pynbs/file.py

Lines 106 to 119 in bd39731

	def __iter__(self):
	if not self.notes:
	return
	chord = []
	current_tick = self.notes[0].tick
	for note in sorted(self.notes, key=lambda n: n.tick):
	if note.tick == current_tick:
	chord.append(note)
	else:
	chord.sort(key=lambda n: n.layer)
	yield current_tick, chord
	current_tick, chord = note.tick, [note]
	yield current_tick, chord

However, because L116 only runs when the tick changes, notes in the last tick of the song aren't sorted.

One extra pitfall: current_tick is taken from self.notes[0], not from the first sorted note. If the list is not already ordered by tick, we could yield the wrong note and yield an empty tick. Even though parsed files are usually already in tick order, building the list manually by hand wouldn't guarantee this.