Re: git: 4191c71fbd22 - main - Mk/Uses/fortran.mk: Make gfortran respect USE_GCC

------- Original Message -------
On Friday, November 18th, 2022 at 8:41 PM, Tijl Coosemans <tijl@FreeBSD.org> wrote:


> 
> 
> On Wed, 16 Nov 2022 21:39:50 GMT Lorenzo Salvadore
> salvadore@FreeBSD.org wrote:
> 
> > The branch main has been updated by salvadore:
> > 
> > URL: https://cgit.FreeBSD.org/ports/commit/?id=4191c71fbd229e5a96382bc6fa271a1ce5668b0f
> > 
> > commit 4191c71fbd229e5a96382bc6fa271a1ce5668b0f
> > Author: Lorenzo Salvadore salvadore@FreeBSD.org
> > AuthorDate: 2022-11-16 14:43:40 +0000
> > Commit: Lorenzo Salvadore salvadore@FreeBSD.org
> > CommitDate: 2022-11-16 21:38:54 +0000
> > 
> > Mk/Uses/fortran.mk: Make gfortran respect USE_GCC
> > 
> > Allow choosing a specific version of gfortran through USE_GCC variable.
> > 
> > PR: 266196
> > Approved by: thierry (fortran)
> > Co-authored by: thierry
> > ---
> > Mk/Uses/fortran.mk | 4 ++++
> > 1 file changed, 4 insertions(+)
> > 
> > diff --git a/Mk/Uses/fortran.mk b/Mk/Uses/fortran.mk
> > index 09ebd62b1a0f..d335fad4dc8e 100644
> > --- a/Mk/Uses/fortran.mk
> > +++ b/Mk/Uses/fortran.mk
> > @@ -14,7 +14,11 @@ fortran_ARGS= ${FORTRAN_DEFAULT}
> > . endif
> > 
> > . if ${fortran_ARGS} == gfortran
> > +. if empty(USE_GCC)
> > _GCC_VER= ${GCC_DEFAULT:S/.//}
> > +. else
> > +_GCC_VER= ${_USE_GCC}
> > +. endif
> > BUILD_DEPENDS+= gfortran${_GCC_VER}:lang/gcc${_GCC_VER}
> > RUN_DEPENDS+= gfortran${_GCC_VER}:lang/gcc${_GCC_VER}
> > F77= gfortran${_GCC_VER}
> 
> 
> When I wrote this file I didn't include this because users will end up
> with multiple versions of GCC installed, each with its own set of runtime
> libraries. So they'll have programs/libraries built against different
> runtime libraries and those don't always work together. For instance,
> science/octopus is now built with GCC 11 but its dependencies like
> lapack are built with GCC 12. These dependencies may require features
> from GCC 12 runtime libraries while science/octopus programs probably
> (I haven't checked) load GCC 11 runtime libraries when you run them.

I do not think it is a big issue if multiple versions of GCC are installed
at the same time. Indeed, USE_GCC exists since a long time and while a few
bugs might arise sometimes, they get fixed eventually and things work fine.
Moreover, if for some fortran dependent port it is better to ignore USE_GCC,
it is sufficient to set USE_GCC=yes and things work just as before this commit.

> Even if this happens to work now it may not work when the default
> switches to 13. I believe it's better for ports like science/octopus to
> have something like this in their Makefile:
> 
> .if ${GCC_DEFAULT} != 11
> IGNORE= This port only works with gcc 11. You can add DEFAULT_VERSIONS+=gcc=11 to /etc/make.conf
> .endif

I think this is a bad idea as:
- it prevents the port to be built on the official packages builder as soon as
GCC_DEFAULT gets updated to 12, so that users that prefer to install software
from packages only cannot install science/octopus anymore;
- adding DEFAULT_VERSIONS+=gcc11 to /etc/make.conf would change the dependencies
of all the gcc dependent ports, not just science/octopus. This could generate
more issues: what if a port does not build with GCC 11 but needs GCC 12+ instead?

> I noticed there's a new version of Octopus so maybe an update would fix
> this particular case.

I hope so, but if Yuri has not done that update yet I guess that the update
is not straightforward. Setting USE_GCC together with this commit allows the
update of GCC_DEFAULT to proceed instead of waiting for science/octopus.
Moreover, GCC 11 is not going away any soon, so, while this is hopefully a
temporary solution, it can safely last many months without any risk to break
science/octopus in the short term.

That said, if you want to revert the commit on Mk/Uses/fortran.mk it is fine
for me as long as another solution is implemented to prevent science/octopus
from blocking GCC_DEFAULT upgrade.
Please note that I also had suggested an alternative solution in
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=266196#c5 :
"the issue can probably be fixed by setting the dependency on gfortran11
explicitely and dropping USE=fortran".

Cheers,

Lorenzo Salvadore