How can I list weak dependencies with dnf?

Question

For example, if I initiate installation of the Greek language meta-package, I am prompted to install its dependencies and weak dependencies.

$ LC_ALL=C sudo dnf install langpacks-el
[sudo] password for roman: 
Last metadata expiration check: 4:03:14 ago on Sat Sep 25 13:17:49 2021.
Dependencies resolved.
===============================================================================
 Package                    Arch      Version                 Repository  Size
===============================================================================
Installing:
 langpacks-el               noarch    3.0-14.fc34             fedora      10 k
Installing dependencies:
 autocorr-el                noarch    1:7.1.6.2-1.fc34        updates     81 k
 langpacks-core-el          noarch    3.0-14.fc34             fedora      10 k
 langpacks-core-font-el     noarch    3.0-14.fc34             fedora      10 k
Installing weak dependencies:
 glibc-langpack-el          x86_64    2.33-20.fc34            updates    512 k
 hunspell-el                noarch    1:0.9-7.fc34            fedora     1.7 M
 hyphen-el                  noarch    0.20051018-23.fc34      fedora     9.3 k
 libreoffice-help-el        x86_64    1:7.1.6.2-1.fc34        updates    3.6 M
 libreoffice-langpack-el    x86_64    1:7.1.6.2-1.fc34        updates    854 k
 mythes-el                  noarch    0.20070412-25.fc34      fedora     161 k

Transaction Summary
===============================================================================
Install  10 Packages

Total download size: 6.9 M
Installed size: 56 M
Is this ok [y/N]:

However, if I try manually listing the dependencies, I don't see the weak dependencies. How can I look them up?

Here is what I tried.

$ LC_ALL=C dnf repoquery --depends langpacks-el
Last metadata expiration check: 3:15:20 ago on Sat Sep 25 14:07:02 2021.
langpacks-core-el
$ LC_ALL=C dnf repoquery --depends langpacks-core-el
Last metadata expiration check: 3:15:42 ago on Sat Sep 25 14:07:02 2021.
langpacks-core-font-el
$ LC_ALL=C dnf repoquery --depends langpacks-core-font-el
Last metadata expiration check: 3:16:08 ago on Sat Sep 25 14:07:02 2021.
dejavu-sans-fonts

According to the manpage:

dnf [options] repoquery [<select-options>] [<query-options>] [<package-file-spec>]

Searches available DNF repositories for selected packages and displays the requested information about them. It is an equivalent of rpm -q for remote repositories.

--depends

Display capabilities that the package depends on, enhances, recommends, suggests or supplements.

Answer 1

dnf repoquery --depends prints only forward dependencies (dependencies listed in the langpacks-el package as Requires/Recommends/Suggests) so it works here as expected because the "extra" packages are brought in via backward/reverse dependencies. The hunspell-el package for example has reverse weak dependency (this dependency is listed in hunspell-el as Supplements) on (hunspell and langpacks-el) meaning it will be installed when you have both hunspell and langpack-el installed. With language packages this allows to install only language packages for packages that are already installed -- you won't get KDE localization (kde-l10n-el also supplements langpacks-el) if you already don't have KDE.

You can print the reverse weak dependencies with --whatsupplements

# dnf repoquery --whatsupplements langpacks-core-el
glibc-langpack-el-0:2.33-20.fc34.x86_64
glibc-langpack-el-0:2.33-5.fc34.x86_64

# dnf repoquery --whatsupplements langpacks-el
gimp-help-el-0:2.10.0-6.fc34.noarch
guayadeque-langpack-el-0:0.4.7-0.27.20210315git37840c1.fc34.noarch
guayadeque-langpack-el-0:0.4.7-0.30.20210415git79ec09d.fc34.noarch
hunspell-el-1:0.9-7.fc34.noarch
hyphen-el-0:0.20051018-23.fc34.noarch
kde-l10n-el-0:17.08.3-10.fc34.noarch
libreoffice-langpack-el-1:7.1.2.2-1.fc34.x86_64
libreoffice-langpack-el-1:7.1.6.2-1.fc34.x86_64
mythes-el-0:0.20070412-25.fc34.noarch
shotcut-langpack-el-0:21.03.21-2.fc34.noarch
tesseract-langpack-ell-0:4.1.0-1.fc34.noarch

I don't think it's possible to print both forward and backward dependencies with one command.