Re: [Fedora-packaging] Re: RPM 4.19: Dynamic subpackages with Python extras

[Miro Hrončok]

On 04. 04. 23 19:24, Dan Čermák wrote:
> Hi Miro,
>
> On March 31, 2023 10:06:14 AM UTC, "Miro Hrončok"  wrote:
> > On 30. 03. 23 23:55, Miro Hrončok wrote:
> > > Hello Python packagers.
> > >
> > > RPM 4.19 introduces this feature:
> > >
> > > https://rpm-software-management.github.io/rpm/manual/dynamic_specs.html
> > >
> > > I decided to write this email to gather my thoughts. I believe that with this, we can turn manual Python extras subpackages like this:
> > >
> > > %package -n python3-...
> > >     Summary:        %{summary}
> > >
> > > %description -n python3-... %_description
> > >
> > > %pyproject_extras_subpkg -n python3-xxx extra1 extra2
> > >
> > > (See https://docs.fedoraproject.org/en-US/packaging-guidelines/Python/#Extras for what that means.)
> > >
> > > Into something like this:
> > >
> > > %package -n python3-...
> > >     Summary:        %{summary}
> > >
> > > %description -n python3-... %_description
> > >     ...
> > >
> > > %install
> > >     %pyproject_install
> > >     ...
> > >     %pyproject_generate_extras_subpkgs -n python3-xxx
> > >
> > > The %pyproject_generate_extras_subpkgs macro would parse the installed .dist-info directory to find out what extras are available and generate subpackages for all of them.
> >
> > One challenge: When an extra is removed upstream, the packager might not notice that it needs to be provided/obsole>
>
> That is indeed a problem. What if we made the macro require the list of subpackages (e.g. as a comma separated string) as an argument? The if the packager wouldn't notice the removal, they'd get a build error.

We already have that today without dynamic subpackages, because when you know 
the list ahead, you can "generate" subpackages already.

$ rpm --eval '%pyproject_extras_subpkg -n python3-... extra1 extra2'
%package -n python3-...+extra1
Summary: Metapackage for python3-...: extra1 extras
Requires: python3-... = %{version}-%{release}
%description -n python3-...+extra1
This is a metapackage bringing in extra1 extras requires for python3-....
It makes sure the dependencies are installed.

%files -n python3-...+extra1 -f 
.../BUILD/%{name}-%{version}-%{release}.x86_64-pyproject-ghost-distinfo

%package -n python3-...+extra2
Summary: Metapackage for python3-...: extra2 extras
Requires: python3-... = %{version}-%{release}
%description -n python3-...+extra2
This is a metapackage bringing in extra2 extras requires for python3-....
It makes sure the dependencies are installed.

%files -n python3-...+extra2 -f 
.../%{name}-%{version}-%{release}.x86_64-pyproject-ghost-distinfo