Re: [PATCH] meson.build: Bump minimum supported version of pixman to 0.34.0

[Thomas Huth <thuth@redhat.com>]

On 11/05/2022 12.28, Peter Maydell wrote:
> On Wed, 11 May 2022 at 10:50, Thomas Huth <thuth@redhat.com> wrote:
>>
>> We haven't revisited the minimum required versions of pixman
>> since quite a while. Let's check whether we can rule out some
>> old versions that nobody tests anymore...
>>
>> For pixman, per repology.org, currently shipping versions are:
>>
>>       CentOS 8 / RHEL-8 : 0.38.4
>>                Fedora 34: 0.40.0
>>               Debian 10 : 0.36.0
>>        Ubuntu LTS 20.04 : 0.38.4
>>      openSUSE Leap 15.3 : 0.34.0
>>             MSYS2 MinGW : 0.40.0
>>           FreeBSD Ports : 0.34.0 / 0.40.0
>>            NetBSD pksrc : 0.40.0
>>
>> OpenBSD 7.1 seems to use 0.40.0 when running tests/vm/openbsd.
>>
>> So it seems to be fine to bump the minimum version to 0.34.0 now.
> 
> This seems to be missing the rationale for why bumping
> the minimum version is worth doing. What new feature that
> we need is this enabling, or what now-unnecessary bug
> workarounds does this permit us to drop?

We simply don't test such old versions anymore. Thus what happens if someone 
tries to use such a version and runs into a problem (especially if it is 
non-obvious and would need a lot of debugging)? Are you still willing to fix 
it? Or would you then rather bump the version after hours of debugging the 
problem? ... IMHO it's better to set the expectations right from the start. 
If we do not test and support it anymore, we should not give the impression 
that QEMU can still be compiled with this.

  Thomas