"excludepkgs" from /etc/dnf/dnf.conf is ignored

[sidt4]

Opening new issue here as per PackageKit/PackageKit#196 (comment):

Issue still seen in Fedora 42, where PackageKit (which uses libdnf) still ignores "excludepkgs".

# cat /etc/dnf/dnf.conf 
[main]
excludepkgs="*"

# dnf install emacs
Updating and loading repositories:
Repositories loaded.
Failed to resolve the transaction:
Argument 'emacs' matches only excluded packages.

$ pkcon install emacs
Resolving                               [=========================]         
Starting                                [=========================]         
Testing changes                         [=========================]         
Finished                                [                         ] (0%)  
The following packages have to be installed:
 emacs-1:30.1-13.fc42.x86_64	GNU Emacs text editor
 emacs-common-1:30.1-13.fc42.x86_64	Emacs common files
 emacsclient-1:30.1-13.fc42.x86_64	Remotely control GNU Emacs
 gdk-pixbuf2-modules-extra-2.42.12-3.fc42.x86_64	Extra image loaders for gdk-pixbuf2
 info-7.2-3.fc42.x86_64	A stand-alone TTY-based reader for GNU texinfo documentation
 libXaw-1.0.16-3.fc42.x86_64	X Athena Widget Set
 libgccjit-15.0.1-0.11.fc42.x86_64	Library for embedding GCC inside programs and libraries
 libotf-0.9.16-6.fc42.x86_64	A Library for handling OpenType Font
 libtree-sitter-0.25.2-8.fc42.x86_64	Incremental parsing library for programming tools
 libtree-sitter-java-0.23.5-1.fc42.x86_64	Java grammar for Tree-sitter
Proceed with changes? [N/y] y

$ pkcon --version
1.2.8

15:19:49	PackageKit-DNF      Using libdnf 0.73.4
15:19:49	PackageKit-DNF      Using librepo 1.19.0

[m-blaha]

PackageKit does respect excludepkgs. However, there is a problem that I am unsure whether should be addressed in libdnf or within PackageKit itself. It appears that PackageKit retains libdnf objects in memory and does not reinitialize libdnf after the configuration file has changed. Consequently, until the service is restarted, PackageKit fails to recognize that a package has been excluded:

❯ cat /etc/dnf/dnf.conf
# see `man dnf.conf` for defaults and possible options

[main]
excludepkgs = acpi

❯ pkcon install acpi
Resolving                               [=========================]         
Loading cache                           [=========================]         
Testing changes                         [=========================]         
Finished                                [                         ] (0%)  
The following packages have to be installed:
 acpi-1.7-24.fc41.x86_64        Command-line ACPI client
Proceed with changes? [N/y] 

The transaction did not proceed.
                                        [=========================]         
Fatal error: user declined simulation


❯ sudo systemctl restart packagekit.service 

 
❯ pkcon install acpi
Resolving                               [=========================]         Package not found: acpi
                                        [=========================]         Package not found: acpi
Command failed: This tool could not find any available package.

[sidt4]

I can confirm the above behavior on Fedora 42.