Make it possible to evaluate arbitrary macros in the context of a given spec file

[michel-slm]

Particular use case: I'd like to be able to query a spec file for the list of its patches. Currently (on Fedora 39's 4.19.1) this is only possible using rpmspec --shell but it requires parsing the output:

❯ echo '%patches' | rpmspec --shell ./*.spec
RPM version 4.19.1.1 macro shell
> %patches
'/home/michel/src/fedora/pkgs/other/slurm/slurm_release_version.patch' '/home/michel/src/fedora/pkgs/other/slurm/slurm_check_version.patch' '/home/michel/src/fedora/pkgs/other/slurm/slurm_html_doc_path.patch' '/home/michel/src/fedora/pkgs/other/slurm/slurm_perlapi_rpaths.patch' '/home/michel/src/fedora/pkgs/other/slurm/slurm_runtime_linking.patch' '/home/michel/src/fedora/pkgs/other/slurm/slurm_to_python3.patch'
> ⏎ 

without shell, rpmspec only allows querying query tags e.g.

$ rpmspec --srpm --query --qf '%{name}\n' ./*.spec
slurm

$ rpmspec --srpm --query --qf '%{patches}\n' ./*.spec
error: incorrect format: unknown tag: "patches"

While rpm allows evaluating anything but only those define by shipped macros, not definitions that are spec file specific; rpmspec does seem to have a -E eval option but it is undocumented and does not seem to work

$ rpm -E '%_sysconfdir'
/etc

$ rpmspec -q -E '%patches' ./*.spec
error: lua script failed: attempt to index a nil value

[Conan-Kudo]

This would be tremendously useful, especially for me trying to dig through really complex packages... Some of them are just not able to be intuited by reading, and being able to probe them like this would be really useful!

[pmatilai]

I'd like to be able to query a spec file for the list of its patches.

rpmspec --srpm -q --qf "[%{PATCH}\n]" <spec>

[pmatilai]

The query is not exactly obvious though, so: #3011

[pmatilai]

BTW it's worth noting that both the patches and sources appear in a reverse order to how they're introduced in the spec. This is basically an internal implementation detail (linked list operation) leaking into the packages, but because it's always been that way, "fixing" would silently break anybody counting on the current behavior :-/

[Conan-Kudo]

Could you fix it for your rpmspec aliases though?

[pmatilai]

After a bit of pondering, filed #3014 instead, we'll revisit the aliases with this is fixed.