MusicXML import/export fairly broken (3.0a2, also some 2.3.2 issues)
Hi. I'm a Wikipedia editor, but also a MuseScore user for several years. I tested the MusicXML import/export in 3.0a2 after writing my Community Wishlist Survey proposal for allowing MuseScore or MusicXML uploads and rendering in MediaWiki (https://meta.wikimedia.org/wiki/Community_Wishlist_Survey_2019/Multimed…). (Basically a team of Wikimedia Foundation staff developers annually take a few software requests, selected by popular vote from a pool of proposals.)
I made a score in 2.3.2, opened it in 3.0a2, saved it, closed it, reopened it, exported it to .mxl, and then opened the new file.
There are at least several issues; some of these are regressions from 2.3.2 and some of these are not. I'm not that familiar with the bug tracker which is why I'm putting this on the forum. It's not clear to me if all of them are MuseScore issues, but regardless I think at least some of them are fairly serious.
* I originally made the score in 2.3.2. After saving in 3.0a2, closing and reopening, there are six extra clefs. (This is not an issue with the export.)
* After exporting, all staves become single-line, but notes are still positioned as if they are on multi-line staves. All 13 of the clefs are gone, too. (Doesn't happen in 2.3.2.)
* The title is right-aligned and bottom-aligned. (Doesn't happen in 2.3.2.) When I deselected "Automatic placement" on that element, some of the other elements moved; for example, the notes were placed onto the lines of the single-line staves. (Not applicable to 2.3.2.)
* The pizzicato and tremolo channel changes are gone. (Also happens in 2.3.2. According to the LilyPond/MediaWiki developer who commented on the proposal, MusicXML should support MIDI instructions.)
* The fretboard diagram is gone.
* One of the custom noteheads is gone.
* The "don't break" element is gone. (Not applicable to 2.3.2.)
* The setting to hide the Hand Clap stave is gone. (Also happens in 2.3.2.)