[Development] HEADS UP: OSX build requirements for 5.7

[Thiago Macieira]

On quinta-feira, 11 de fevereiro de 2016 03:04:52 PST Tim Blechmann wrote:
> > Regardless of whether that is a valid approach or not, the fact that
> > people
> > are doing that poses a problem for us. If we write code against the latest
> > toolchain, it may not compile against older ones people might be using.
> 
> this implies bumping the minimum requirements. for some use cases this
> might be acceptable, for others it isn't.

According to Apple, it is...

> > That can be because we used new features that aren't present in older
> > ones,
> > even if properly runtime checked.
> > 
> > Another problem is that the compilers in the old toolchains are older,
> > with
> > older libc++ and with bugs that we aren't testing for.
> 
> ... or newer toolchains can introduce regressions ...

But we usually detect those and work around them. It's bad, but better than 
the alternative: when we don't detect an issue because we're not testing that 
toolchain.

> > If we're going to upgrade our Xcode in all our builds, I would advise we
> > also make it mandatory for everyone else too. Check during configure
> > against the minimum SDK version, that being the *current* at the time of
> > release.
>
> so what happens when you are hit by a toolchain regression? i'm not
> voting for having code compiling with gcc-4.2 or any of the llvm-gcc
> flavors which were around during that time. however qt is a framework
> and it should support more than one toolchain so that people who are hit
> by toolchain bugs still have an alternative ...

Put up with it and complain to Apple? :-/

Seriously, this guidance is coming from your OS and toolchain vendor. If you 
don't like it, you should consider another vendor. They're not going to change 
their practices if people keep putting up with them.

To be clear, I'm not in favour of dropping support for older toolchains. I'd 
rather we kept testing them, to reasonable amounts (we can't test every Xcode 
release on every OS X host). I'd rather Qt shielded people from bad practices 
from vendors. 

But as often happens whenever a topic like this comes up: there's a resource 
constraint.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center