The project file does not store variables with formatted text

[pigreco]

The idea is taken from here, but if I create project variables and paste the letters, when the project is reopened I CANNOT find the letters in the project variables anymore !!!

how to reproduce it:

1. add a project variable;
2. paste some formatted letters, ex: 𝒶, 𝒷, 𝒸, 𝒹, 𝑒, 𝒻, 𝑔, 𝒽
3. close the saved project;
4. reopen the project: the variable is empty !!!

reopening the project:

OSGeo4W64 WIN 10 QGIS 3.16.3 Hannover

[elpaso]

I think it's an upstream bug: https://bugreports.qt.io/browse/QTBUG-25291 <--- this is actually closed but if you run the same test case in 5.15.2 it still fails (a bit differently because it fails early, so the situation is even worse than that it was in the original issue).

[elpaso]

Side note: storing 4-bytes utf-8 works in XML attributes, it does not in QTextNode and CDATA section.

[kannes]

Any chance one of you could notify upstream about the issue being valid for Qt 5(.15.2 or more)?