Bold isn't working on MacOS

[Cuperino]

Bold isn't working...

[Cuperino]

This bug is back for v1.1 betas.

[Cuperino]

Bug is in Qt and it seems to be fixed in the KDE Patch Collection.

[Cuperino]

Bug is still present in v1.1.2 and v1.1.3, but only under macOS. It affects both Apple SiIlicon and Intel CPUs. All fonts are affected. It's affecting Qt 5.15.8 with the KDE Patch Collection.

[Cuperino]

@Douglas-Cox, thank you for writing.

You've found a really really old bug I believed to have fixed, but it has either returned, or it never really left; and it's affecting macOS exclusively.

The good news is I'm now aware of it. The bad news is that there's nothing I can do for now, for all the steps that it would take to fix this bug in other platforms have been taken in macOS as well, and yet the bug persists.

The bug has been caused by a variety of reasons in the past, most of which have been successfully and permanently addressed. The current problem lies not in QPrompt's code, but somewhere in the Qt Framework, which is the set of libraries over which QPrompt is built upon. There are two currently supported branches of Qt, versions 5 and 6. I won't go into details about them.

I use Qt versions 5.15.x to build QPrompt because another library that QPrompt is built upon, unfortunately, is incompatible with Qt 6. This bug has been fixed in Qt 6, and the fix has been backported to Qt 5 by the KDE community as part of the KDE's Qt Patch Collection.

QPrompt uses KDE's Qt Patch Collection,, which is not supposed to have this bug. Unfortunately, not all patches in the collection are available for all platforms. I have no control over the state of these patches, only whether I choose to use them or not. Not using the Patch Collection in QPrompt results in other bugs with other frameworks, so, for QPrompt, it is best to use them on all platforms until we're able to build and distribute QPrompt with Qt 6.

I won't be working on this issue because it goes very deep, meaning it would take away a lot of time I could spend in other ways, and because I should finally be able to port QPrompt to Qt 6 later this year, in possibly less time than it would take me to fix the bug in Qt 5.

I apologize for the inconvenience, and I hope the port to Qt 6 flows smoothy so the issue is fully fixed once and for all.

In the meantime, if you need to run QPrompt free from this issue, I recommend installing Linux or Windows in one of your computers and running QPrompt from there. QPrompt performs best on Linux systems running KDE Plasma, such as Asahi Linux and KDE neon.

[Douglas-Cox]

@Cuperino - thanks very much for the detailed information. Totally makes sense that this is a library issue, and I see the history that you've gone through mitigating this on other platforms. Will definitely take a look at running on an alternate platform. Thanks again!

[Cuperino]

Re-tested this issue as of today, using the latest Qt 5 open source, version 5.15.10. The issue sadly continues to be present on MacOS.

[Cuperino]

Issue still present using Qt 6.7.2.