MuseScore adds nonexistent rests when importing XML and then thinks it's a corrupt file

[ChrisAm1224]

Issue type

Opening/saving issue

Bug description

No response

Steps to reproduce

Open "Brahms 4th Symphony, Andante Moderato Viola m 86 issue with MuseScore.SHY.xml" in
MuseScore issues.zip
This alert appears:

Click Open anyway. Display looks like this:

MuseScore has added a rest in the end and some tuplets, both of which are not in the original XML, which is supposed to look like this:

In order to avoid the curruption message, you can open "Brahms 4th Symphony, Andante Moderato Viola m 86 issue with MuseScore fixed.SHY.xml" which contains an additional invisible rest, but why is this necessary? And why are tuplets being added that are not in the original XML?

Screenshots/Screen recordings

No response

MuseScore Version

OS: Windows 10 Version 2009 or later, Arch.: x86_64, MuseScore Studio version (64-bit): 4.3.0-241231433, revision: github-musescore-musescore-5f36e74

Regression

No.

Operating system

Windows 11

Additional context

No response

[Jojo-Schmitz]

Same issue with Mu3, Not with Mu2 or Mu1 though

[Jojo-Schmitz]

Might be related to (the root cause of) #22344

[ChrisAm1224]

Might be related to (the root cause of) #22344

not sure though, since 22344 seems to be about export, but this problem is about import

[Jojo-Schmitz]

True. But is is about rounding issue due to musicxml im- and export not yet using Fraction, something that got introduced with Mu3, pretty much the last thing before release

[ChrisAm1224]

In the example in this bug (Brahms 4th Symphony, Andante Moderato Viola m 86 issue with MuseScore.SHY.xml), divisions is 24 (i.e., the duration of a quarter note). The file consists of all sixteenth triplets, i.e., duration = 4, (one sixth of a quarter note), no rounding error happening here. The issue seems to be that because of the time modification, MuseScore seems to recognize (correctly) that the notes are triplets. It then tries to group them in groups of three (adding the tuplets that are not there either). In the file, after the alto clef (and the backup tag) there are only two notes in a group (beam), and then another three. MuseScore assumes (incorrectly) that all groups must consist of three notes and then in order to force that, just adds a rest in the end (or that's the best explanation that I can come up with; I haven't checked any source code).

In 22344 what I see is divisions = 160, and 7 septuplet notes with duration 23 each, and 7 * 23 = 161, which could qualify as a "rounding error". There are two ways to fix that
(1) make divisions a multiple of 7
(2) if that overflows (because least common multiple might be too large), make one of the notes (in the middle somewhere) duration 22 so the sum is 160. I've seen other software do this.
I see that 22344 has already been solved, I'm curious what the solution will be there.