F36 Change: Enable exclude_from_weak_autodetect by default in LIBDNF (System-Wide Change proposal)

[Ben Cotton]

https://fedoraproject.org/wiki/Changes/ExcludeFromWeakAutodetect

== Summary ==
exclude_from_weak_autodetect enables autodetection of unmet weak
dependencies (Recommends or Supplements) of installed packages and
blocks installation of packages satisfying already unmet dependencies.
In other words: When you don't have the recommended package installed,
it won't be automatically installed with future upgrades of the
recommending package.

== Owner ==
* Name: [[User:jmracek| Jaroslav Mracek]]
* Email: [e-mail]

== Detailed Description ==
The feature is designed to prevent an install of removed weak
dependencies from the system by users and to not install weak
dependencies missing after system deployment. It will change the
behavior of DNF, microdnf, and PackageKit. The feature will be
backported to all Fedoras, but in default, the feature will be off.
Additional information: https://bugzilla.redhat.com/show_bug.cgi?id=1699672

The default value for exclude_from_weak_autodetect configuration can
be overridden in `/etc/dnf/dnf.conf`

== Feedback ==
The feature was requested by [[User:Churchyard|Miro Hrončok]] and
supported by many others: See
[https://bugzilla.redhat.com/show_bug.cgi?id=1699672 rhbz#1699672] for
more feedback.

== Benefit to Fedora ==
After the installation of a fresh system, the first upgrade will not
install a lot of weak dependencies. Some of them were excluded from
the kick-start installation set for good reasons (security, image
size, minimal functional set, ...), but after the first update, all
weak dependencies are installed, therefore some features of deployment
simply disappear.

== Scope ==
* Proposal owners:
** The feature is ready in Pull Request -
https://github.com/rpm-software-management/libdnf/pull/1279
** PRs only wait for a release of libsolv
** The Feature will be enabled in upstream as default, therefore from
Fedora 36, we start to release libdnf without a revert patch of
default in comparison to upstream.

* Other developers: The change requires a new release of libsolv.

* Release engineering:
* Policies and guidelines: A packaging guideline should be added that
discourages or forbids weak dependencies on fully versioned
(sub)packages (see
[https://bugzilla.redhat.com/show_bug.cgi?id=1699672#c44 the
details]).
* Trademark approval: N/A (not needed for this Change)
* Alignment with Objectives:

== Upgrade/compatibility impact ==
No manual changes will be required. After the libdnf update, this
feature will be on by default.

== How To Test ==
1. Install package without satisfied weak dependencies
2. Upgrade the upgrade. With exclude_from_weak_autodetect=true, it
will not install weak dependencies of already installed packages. With
exclude_from_weak_autodetect=false, weak dependencies will be
installed during upgrades.

== User Experience ==
The change in default will help to keep some values for particular
deployments (a minimal system will be still minimal without disabling
weak dependencies).
Users will be able to remove particular weak dependencies and they
will be not installed on the first upgrade.
In case when the feature will not work according to the user
expectation it can be switched off in the dnf configuration file.

== Dependencies ==
libsolv - Required code changes are already in the libsolv upstream.
We only wait for the next libsolv release.

== Contingency Plan ==

There are no external dependencies, therefore we can easily postpone
the feature and the change of default behavior.

* Contingency mechanism: (What to do?  Who will do it?)
* Contingency deadline: beta freeze
* Blocks release? No

== Documentation ==
The feature will be documented in dnf man pages.