On Fri, Apr 3, 2020 at 1:27 PM Matthew Miller <mattdm(a)fedoraproject.org> wrote:
On Thu, Apr 02, 2020 at 10:32:31PM +0200, Nicolas Mailhot via devel wrote:
> Would it be possible to formalize the kind of spec processing ELN wants
> available in a set of generic operations with generic arguments (or
> control variables)?
>
> I would not mind seeing a set of ELN macro calls in my rawhide specs,
> that evaluate to nothing for Fedora. *declarative* syntax is a lot less
> scary maintenance-wise than free-form spec programming.
This seems like a great suggestion in general and the direction we should be
going anyway.
Fabio Valenti made this comment in the FESCo ticket[1].
"Side note: I think more people would be amenable to including
"conditionals" into their packages if they weren't only shown off as
`%if eln this else that`. I think there's more value in doing "feature
flags" rather than conditionalize everything based on the `dist` tag,
for example something like this might even be useful in fedora
branches (e.g. for bootstrapping):
```spec
# at the top of the .spec file, where it's easily visible
%if 0%{?eln}
%bcond_with docs
%else
%bconf_without docs
%endif
# ...
%if %{with docs}
# do something
%endif
```
This makes conditionals (when they are necessary) much easier to
maintain (and understand), in my experience."
First, let me say that I agree wholeheartedly and I think that when
we're using conditionals this is the best way to do it.
I had some thoughts here on how we could accomplish the above without
cluttering the spec file (though it does add a bit of complexity to
the dist-git contents). We could take a page from build-systems and
have essentially a separate "configure" and "build" step for RPM.
(No,
I'm not proposing changes to RPM itself).
At the top of the specfile (above even the `Name:` directive), we
would have constructs of the following type:
%if 0%{?rhel} < 9
%include rpmconfig_rhel_old.inc
%elif 0%{?rhel} >= 9
%include rpmconfig_rhel_new.inc
%else
%include rpmconfig_fedora.inc
%endif
Contents of rpmconfig_rhel_old.inc:
%bcond_without pregen_docs
%bcond_with openssl3
Contents of rpmconfig_rhel_new.inc:
%bcond_without pregen_docs
%bcond_without openssl3
Contents rpmconfig_fedora.inc:
%bcond_with pregen_docs
%bcond_without openssl3
Then the main specfile can use the `%if %{with FEATURE}` construct
instead of dealing with the clutter in the main specfile (and merges
will likely be easier).