[Development] Proposal to raise the minimum CMake version needed to build and use Qt 6.12

[Albert Astals Cid]

El dimarts, 12 de maig del 2026, a les 14:44:39 (Hora d’estiu d’Europa 
central), Alexandru Croitor va escriure:
> Hi Albert!
> 
> > On 4. May 2026, at 18:48, Albert Astals Cid <aacid at kde.org> wrote:
> > 
> > Just as a somewhat related data point, in KDE Frameworks we are requiring
> > cmake 3.29 now.
> > 
> > No one seems to have complained about it.
> 
> Was there any discussion or reasoning on how the KDE developers decided to
> use that version as the minimum?
> 
> I would have liked to require a newer version for Qt as well, but
> unfortunately there are more points that need consideration.

There was a bit (not much) discussion and we ended up agreeing with this 
policy


The minimum required cmake version for KDE Frameworks will be the maximum of:

 * The required cmake version of required Qt at that time
 * The cmake version released 1 year before the required Qt at that time
 * Updating major cmake versions should be discussed in the frameworks 
development mailing list and not done automatically because of point B) of 
this policy

Example:

 required Qt at the time = 6.9
 required cmake version of Qt 6.9 = 3.16
 Qt 6.9 release date = 2 April 2025 
 
 cmake 3.29.0 release date = 21 March 2024
 cmake 3.30.0 release date = 19 July 2024
 
 cmake version released 1 year before the required Qt at that time = 3.29
 
 minimum required cmake version = max(3.29, 3.16) -> 3.29

Cheers,
  Albert

P.S: You can see my original email at 
https://mail.kde.org/pipermail/kde-frameworks-devel/2025-December/123726.html