Description of problem:
The yum by default was showing a dependency resolution tree like this:
Resolving Dependencies
--> Running transaction check
---> Package httpd.x86_64 0:2.4.6-40.el7.centos.4 will be erased
--> Processing Dependency: httpd = 2.4.6-40.el7.centos.4 for package: httpd-manual-2.4.6-40.el7.centos.4.noarch
--> Running transaction check
---> Package httpd-manual.noarch 0:2.4.6-40.el7.centos.4 will be erased
--> Finished Dependency Resolution
Dependencies Resolved
dnf does not display anything about dependency resolution process. It was usefull when one wants to find out why certain package is e.g. brought as a dependency on update. I do not see a way how to achieve this now.
If option is not suitable, the other way that comes to my mind is something like a "print" option to a dnf shell resolvedep command. This would allow an experienced user to understand the resolution of dependencies and why certain packages are installed/erased or how to avoid it.
This is quite difficult.
YUM3 did dependency resolution as a recursive dependency closure.
DNF uses libsolv, which is a SAT solver, which works differently.
It's a black-box to DNF.
However we'll check if we can't get any additional information from libsolv and display it on demand (possibly in verbose or debug mode).
I have a good news - there is a new feature in libsolv that allows to answer the question why package is in transaction
run:
# `dnf install <argument> --debugsolver`
$ cd debugdata/rpms/
$ testsolv -W acpi-1.7-20.fc38.x86_64 testcase.t
installed acpi-1.7-20.fc38.x86_64@fedora:
job install one of acpi-1.7-20.fc38.x86_64