[Development] Proposal to raise the minimum CMake version needed to build and use Qt 6.9

[Alexandru Croitor]

> On 13. Nov 2024, at 16:01, Alexandru Croitor <alexandru.croitor at qt.io> wrote:
> 
> 
> 
>> On 13. Nov 2024, at 15:38, Sune Vuorela <nospam at vuorela.dk> wrote:
>> 
>> On 2024-11-13, Alexandru Croitor via Development <development at qt-project.org> wrote:
>>> Which debian stable version are you using?
>> 
>> Debian stable is debian 12. It ships with 3.25.
>> 
>>> Is it unreasonable to ask to install cmake from one of those official repos?
>> 
>> Backports are not part of stable, so yes, I would consider that is unreasonable.
> 
> Do you consider it unreasonable due to backports being 'backports', so not 'stable', thus you are completely against installing any software from there? 
> 
> Or is it more specific that you think that the backports-provided cmake will not be stable enough for building software?
> 
> CMake is generally very good in regards to compatibility and building older and newer projects. 
> 
> While I can relate to the 'only-use-stable' sentiment, I think it's somewhat too harsh of a requirement in this case.
> 
> Enforcing a lower cmake version requirement just for development work, when the specific debian versions will not be used for
> building / shipping / packaging Qt 6.9 for the larger open source community, seems a bit of an uneven trade-off.
> 
> Especially when it's easy to just install a specific standalone kitware-provided cmake binary into a custom location, and use
> that only for specific projects.

I will also point out that we likely won't be raising the cmake version in the coming years after this.

At the same time, debian 13 will release sometime mid-2025? with a newer cmake version.

So maybe half a year of using a non-stable easily-acquirable cmake for development work isn't too much to ask?