Guidelins for one codebase that builds with Qt5 and Qt6?

[Halla Rempt]

On woensdag 7 augustus 2024 10:16:56 CEST Milian Wolff wrote:
 
> QLinkedList is available in Qt6 core5compat:
> https://doc.qt.io/qt-6/qlinkedlist.html

Yes, that's what I'm currently using. The other option would be porting to std::list, but that gives a risk of bugs because it's not exactly the same.

> We recently ported KDevelop over to Qt6 and ran into issues with the gitlab 
> configuration - branches must not contain more than a hundred patches, which 
> you can easily end up with while porting larger applications.

We had that problem with some feature branches, so...

> 
> We ran into this, as we did _not_ want to try and support Qt5 and Qt6 
> simultaneously. Since you want to do that, I can only recommend you to get 
> your porting patches into master incrementally, in smaller batches. Otherwise 
> you will need to start gaming the system and workarounding the artificial 
> gitlab patch limitations.

That's what I'm intending to do.

 
> > That's going to take quite a bit of time for us, since we really needed a
> > lot of patches to Qt itself to make things like HDR work.
> 
> Are those patches not upstreamed to Qt6?

No. We just couldn't afford the time to game the gerrit review process.

> 
> 
> I agree with Volker. Compared to the past, porting QtWidgets applications from 
> Qt5 to Qt6 is trivial. I fear you krita folks will have more trouble due to 
> the low level graphics work you are doing, but I hope that the bulk of the 
> effort is going to be trivial. Definitely start with porting everything to the 
> latest Qt 5.15 and fix deprecation warnings, then take it from there.
> 
> Good luck!

Thanks!