Re: minimum Meson version

On 17.06.25 19:36, Peter Eisentraut wrote:
> meson.build currently says
> 
> # We want < 0.56 for python 3.5 compatibility on old platforms. EPEL for
> # RHEL 7 has 0.55. < 0.54 would require replacing some uses of the fs
> # module, < 0.53 all uses of fs. So far there's no need to go to >=0.56.
> meson_version: '>=0.54',
> 
> Since the current minimum supported Python version is now actually 3.6, 
> we could update this a bit.
> 
> The first Meson version to require Python 3.7 is 0.62, so we should stay 
> below that.
> 
> Moving to 0.55 and 0.56 would get rid of some future-deprecated warnings.
> 
> There is some conditional code for 0.57 and 0.59, so landing on either 
> of these would allow getting rid of some of that.
> 
> I see that Rocky Linux 8 ships with Meson 0.58.2 [0], so maybe that is a 
> good target to aim for.  (I don't know if that carried over from RHEL 8 
> or is their own doing.)  But there aren't any compelling features new in 
> 0.58 (format strings seem nice but are pretty much cosmetic), so maybe 
> setting the minimum to 0.57 is enough.

Ok, let's make a small start.  Here is a patch set that moves the 
requirement to >=0.57.  As explained above, this allows getting rid of a 
bunch of conditional code and the future-deprecated warnings.

There is one mention that I didn't dare touch:

if have_gssapi
   # Meson before 0.57.0 did not support using check_header() etc with
   # declare_dependency(). Thus the tests below use the library looked up
   # above.  Once we require a newer meson version, we can simplify.
   gssapi = declare_dependency(dependencies: gssapi_deps)
endif

I didn't quite understand what was meant by this.  This code is 
relatively new, so maybe someone who worked on it still remembers and 
can offer a suggestion.

Along the way, I also found that our meson.build always issues a warning 
when run on Windows/msvc, which I fixed.  (Should probably be backpatched.)

To help find all the places to update for deprecations etc., I used the 
option meson setup --fatal-meson-warnings.  This seems quite useful, so 
I'm also suggesting adding it to the CI tasks.  I think this could be 
useful in general, as I've seen more than zero times someone submitting 
a patch that accidentally violates the meson version requirement in some 
way, and we might as well catch those early.