Renders all texts with the same (fallback?) font on a particular system

Addendum: When exported to pdf, all fonts+settings are applied correctly, i.e. only the view is affected.
I am also on archlinux x86_64 btw. Downgrading to 3.1 still shows the font rendering issue (so this might well be an issue with the qt5 version [which is 5.13.0-7]?)

In order to investigate, we would need you to attach the specific score you are having problems with. All works perfectly in all scores I have tried.

As the initial post by gts says, it does not matter which fonts you choose or which score you work on. I have attached a score that does not work for me along with its corresponding screenshot and pdf.

As the initial post by gts says, it does not matter which fonts you choose or which score you work on. I have attached a score that does not work for me along with its corresponding screenshot and pdf.

Here's the inner workings:

          <Chord>
            <durationType>quarter</durationType>
            <Lyrics>
              <text>Georgia</text>
              </Lyrics>
            <Note>
              <pitch>72</pitch>
              <tpc>14</tpc>
              </Note>
            </Chord>
          <Chord>
            <durationType>quarter</durationType>
            <Lyrics>
              <text><font face="Arial"/>Arial</text>
              </Lyrics>
            <Note>
              <pitch>74</pitch>
              <tpc>16</tpc>
              </Note>
            </Chord>
          <Chord>
            <durationType>quarter</durationType>
            <Lyrics>
              <text><font face="Fira Sans"/>FiraSans</text>
              </Lyrics>
            <Note>
              <pitch>76</pitch>
              <tpc>18</tpc>
              </Note>
            </Chord>
          <Chord>
            <durationType>quarter</durationType>
            <Lyrics>
              <text>DroidSans</text>
              </Lyrics>
            <Note>
              <pitch>77</pitch>
              <tpc>13</tpc>
              </Note>
            </Chord>
 

Georgia and Droid Sans are using the default font, as per the style settings, FreeSerif. Fira Sans falls back to MS Shell Dlg 2 on my system, as Fira Sans is not available/installed here (Droid Sans isn't either). Arial works just fine.
(Georgia would work, if specified correctly)

So far everthing as by design, no bug.

I understand why you think that this would be "by design" from your point of view, however:
- Font rendering/display with these fonts (well, any font actually) worked in previous iterations of MuseScore.
- Even though all of the fonts listed are installed on my machine, none of them render correctly, all are replaced with some default/fallback font (as can be seen in the attached screenshot)
- pdf export does consider all of the specified fonts correctly
- Regarding Georgia: I chose Georgia from the font dropdown while in enter lyrics mode, so it was not I who did not manage to have it "specified correctly"

Looking at the mscx file (as per the above snippet) no other MuseScore version could possible ever have rendered that differently.

That might be the case, but the issue is still real.
However, if nothing in MuseScore's way of rendering text/handling fonts has changed, then perhaps it's actually a QT (and or QT ←→ musescore interaction) issue. I will report back if I find anything.

What do you perceive the real issue to be, then? If a score specifies a font, and that font is not present on your system, then MuseSore cannot display that font. This is not an "issue", it's simply reality. If you are saying there is a case where your score specifies a font, and that font is present on your system, and yet it does not render correctly, then there is indeed an issue, but so far, we're not seeing evidence of this. Unless you are saying that those named fonts are all present on your system and are installed normallly?

There is a case where my score specifies a font, and that font is present on my system, and yet it does not render correctly. (And even if it were not present on my system, why would the font selection dropdown list that font and allow me to select it?). I've attached yet another score and some more screenshots.
Also, as I already mentioned above, I did not have any font issues with earlier versions of MuseScore (and I didn't add or remove any fonts since).

Edit: The _pdf_export.png is a screenshot of the exported pdf. Some days ago, MuseScore displayed these fonts properly in MuseScore itself, somehow now it doesn't do that anymore (as can be seen in die _mscore.png).

OK, seems likely indeed to be some sort of installation / Qt version issue. Unfortunately, the number of permutations of possibilities on Linux approaches infinite, so it's practically inevitable some combinations won't work. Did you try the AppImage, which is usually the best-supported version?

FWIW, we don't officially support Qt 5.13 that I know of, although I could certainly be out of date on that.

The AppImage (being almost self contained) works, so I guess it really is Qt 5.13 related. I didn't know MuseScore does not officially support Qt 5.13 (yet?).

Well, Qt 5.13 at least is not an LTS releases, like 5.9 and 5.12. We build and test against those. So I guess 5.13 will never be supported really.

In that sample score the settings are at least correct:

          <Chord>
            <durationType>half</durationType>
            <Lyrics>
              <text><font face="Farsan"/>ThisIsFarsan</text>
              </Lyrics>
            <Note>
              <pitch>72</pitch>
              <tpc>14</tpc>
              </Note>
            </Chord>
          <Chord>
            <durationType>half</durationType>
            <Lyrics>
              <text><font face="Impact"/>ThisIsImpact</text>
              </Lyrics>
            <Note>
              <pitch>74</pitch>
              <tpc>16</tpc>
              </Note>
            </Chord>
 

But of course it falls back to some default fonts when those fonts are not available, like on my system