Note: This is a public test instance of Red Hat Bugzilla. The data contained within is a snapshot of the live data so any changes you make will not be reflected in the production Bugzilla. Email is disabled so feel free to test any aspect of the site that you want. File any problems you find or give feedback at bugzilla.redhat.com.
Bug 1533878 - [rfe] dnf option to display dependency resolution tree (transaction check)
Summary: [rfe] dnf option to display dependency resolution tree (transaction check)
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: dnf
Version: rawhide
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: rpm-software-management
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
: 1549851 (view as bug list)
Depends On:
Blocks: 1266761 1162409 1213995 1224466 1268174 1300669 rel-eng-dnf
TreeView+ depends on / blocked
 
Reported: 2018-01-12 13:03 UTC by Adam Pribyl
Modified: 2023-08-23 14:41 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed:
Type: Bug
Embargoed:

Attachments (Terms of Use)

Description Adam Pribyl 2018-01-12 13:03:06 UTC 
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.
Comment 1 Daniel Mach 2018-01-17 12:44:14 UTC 
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).
Comment 2 Jaroslav Mracek 2023-08-23 06:06:10 UTC 
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
Comment 3 Jaroslav Mracek 2023-08-23 06:21:24 UTC 
*** Bug 1549851 has been marked as a duplicate of this bug. ***
Note You need to log in before you can comment on or make changes to this bug.