Re: RFC: Feature macros (aka USE flags)

[Vít Ondruch]

Dne 27. 04. 20 v 16:25 Petr Šabata napsal(a):
> On Mon, Apr 27, 2020 at 3:01 PM Vít Ondruch  wrote:
> > Dne 27. 04. 20 v 13:19 Petr Šabata napsal(a):
> > > Based on the recent discussions around %fedora/%rhel macros and ELN,
> > > and %bcond generally being confusing to work with, I came up with a
> > > distribution-wide feature that defines generic feature keywords and
> > > associated helper macros that packages can check in build-time
> > > conditionals.
> >
> > The most confusing part of the %bcond is the definition itself. The rest
> > is fine IMO. Therefore, I somehow don't understand why would you like to
> > replace:
> > %if %{with ssl}
> > BuildRequires:  openssl-devel
> > %endif
> >
> > by
> > %if %{use ssl}
> > BuildRequires:  openssl-devel
> > %endif
>
> The difference here is %use defaults are defined by the buildroot
> while %with %bconds are defined by the package.

Looking at the provided example and the binary RPM and what not, I am
still confused and it is not clear to me what you actually want to achieve.

I think the biggest issue I have is that you seems to propose to use the
`%{use ssl}`, `%{use_enable ssl openssl}` and `%{?_use_ssl:-DSSL}` in
places, where it would make more sense to use the well established
`with/without` rpm(build) macros.

Also, this `%{use_enable ssl openssl}` for example looks like you have
some distribution wide `ssl` feature, but you want to locally implement
it via openssl and moreover it seems you are trying to address the case
where `configure` does not accept with/without but enable/disable
instead (which was probably not an issue so far, otherwise rpmbuild
would probably provide enable/disable options alongside with/without).

IOW it could be probably better if there was something like `%{use ssl
openssl}` call on top of the .spec file, which would enable use of
standard RPM macros instead of introducing set of new macros. This would
also make the `general availability` section much shorter, because there
would be probably need to check the macro existence on a single place.

Vít
> > Also I don't understand, why there is exposed some underscore macro,
> > such as `make test %{?_use_ssl:-DSSL}`. Shouldn't the underscore macro
> > be just implementation detail? For `%bcond`s, the `_with` macros are
> > discouraged, so why would you encourage them?
>
> Yes, this should be an internal detail. I'd like to replace this with
> %use_defined or something similar.
>
> P
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