[Development] Proposing CMake as build tool for Qt 6

[Christian Gagneraud]

On Mon, 17 Jun 2019, 20:15 Elvis Stansvik, <elvstone at gmail.com> wrote:

> Den mån 17 juni 2019 kl 09:12 skrev Christian Gagneraud <chgans at gmail.com
> >:
> >
> > On Mon, 17 Jun 2019, 18:11 Jedrzej Nowacki, <Jedrzej.Nowacki at qt.io>
> wrote:
> >>
> >> On Saturday, June 15, 2019 6:37:24 PM CEST Thiago Macieira wrote:
> >> > On Saturday, 15 June 2019 02:18:28 PDT Jean-Michaël Celerier wrote:
> >> > > You can download a CMake static binary (https://cmake.org/download/)
> that
> >> >
> >> > (...)
> >> >
> >> > I would prefer that our requirements be present in Linux
> distributions we
> >> > declare are supported build environments. If nothing else, our CI will
> >> > benefit from this.
> >>
> >> Let's not pull CI into it. It already
> >
> >
> > Wow! Let's not pull in the system which only goal is to validate the
> "supported platforms" promise, is it what you mean?
> > If I need a special cmake to build Qt, then this should be shipped as
> part of Qt itself, another third-party source tree.
> > And then it means that I will need to build qt's build system. In other
> words, I'll have to bootstrap Qt build system.
> > I thought that it was a big no-no. The main argument to ditch qmake and
> qbs...
>
> Hm, what is the problem with using the official CMake binaries? Isn't
> that what you'd do on Windows / macOS anyway?
>

In case you didn't follow the thread, building Qt with cmake requires a
non-released version of cmake.

The question is:
By the time qt6 will be out, will the requirement of cmake minimum version
be met by, say, the latest (two) Ubuntu LTS release? (Or Macos, ...)


The answer is that, best case, this is doable if qt6 is not released before
2022 or 2024. (Current req. Is unreleased cmake 2.15. assuming the minimum
req. is not bumped, which is very unlikely given the lack of support for
Android, iOS, etc...)


> If distro X (e.g. *buntu 20.04) happen to ship a sufficient version
> when it arrives, then great. But having to install the build tool from
> the vendor instead of the distro package manager surely can't be a
> blocker
>

Really? Then convince the boot2qt team to force yocto to use the latest
bleeding edge cmake version for their stable branch...
Good luck with that.

And then, which is my point, you're asking your customers to build/install
Qt build system in order to build Qt itself.
That is wrong. The world is not spinning around Qt, sorry for the bad news.
I prefer a transparent self-bootstrapped Qt over an explicit two stages one.

Right now the cmake build system doesn't respect the initial requirements
that were used to ditch contenders.

This is in no way a democratic process.
This is selective hearing, reqs for cmake are artificially lowered while
reqs for contenders are artificially raised.

I have no doubt that cmake will be Qt6 build system, this is your choice,
I'm just asking to stop this simulation, and I'm asking you to take your
responsibilities, if building Qt6 is not supported on mainstream platforms
I might consider switching away from Qt.

Last comment: Please think about embedded Linux, qnx, vxworx, iOS, android
and whatever next os is coming.
Cmake is not yet ready for that.

Chris




> Elvis
>
> >
> > Chris
> >
> >
> >> covers installation of the cmake in
> >> order to test wip/cmake branch (
> https://code.qt.io/cgit/qt/qt5.git/tree/coin/
> >> provisioning/common/linux/cmake_linux.sh?h=wip/cmake)
> >>
> >> Cheers,
> >>   Jędrek
> >>
> >>
> >> _______________________________________________
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> >> Development at qt-project.org
> >> https://lists.qt-project.org/listinfo/development
> >
> > _______________________________________________
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>
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