#1505 Being able to prefer packages on distribution level
Closed None Opened 5 years ago by jsilhan.

= phenomenon =
Packages that take advantage of Provides tag and two packages provides the same name without the version specified, they are treated equally. No one has greater preference than the other and so the dependency solver like the one in DNF or PackageKit can practically choose any of them during the resolution even though from user, packager or distribution point of view, one package is obviously superior [1].

= reason =
Missing mechanism how to prefer packages on distribution level.

= recommendation =
We have designed solution for preferring packages within distribution [2] when using DNF, PackageKit and Gnome Software. The first two sections of the page (user and package maintainer preference) are obvious and already approved. The third section covers Provides selection mechanism on distribution level.

There are 3 issues that needs to be decided:

1) '''whether the definition of rules could be in fedora-repos package'''

Hints (rules) with prioritized packages for depsolver needs to be saved in the package that is installed by default on every Fedora instance. We have identified fedora-repos package to be a good candidate for storing these metadata so we don't need to introduce the new metapackage.

2) '''approve the first bunch of preferred packages''' (mariadb and sendmail). That means getting these lines into fedora-repos subpackage:
{{{

definition of Fedora preferred packages

https://fedoraproject.org/wiki/PackagingDrafts/ProvidesPreferences#Distribution_preference

Suggests: mariadb
Suggests: sendmail
}}}

3) '''define how would the future process of getting new preferred packages into fedora-repos look like'''. Note: we have got feedback from stack holders, that any complicated process that would go through FESCo, would discourage packagers from using this mechanism.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1192182

[2] https://fedoraproject.org/wiki/PackagingDrafts/ProvidesPreferences#Distribution_preference


I'm ok with the general plan here, but I don't think we should prefer sendmail. I'd say postfix for that.

+0.5 with general plan

But the preferred software should be pre-approved separately by FESCo and relevant WG. Though I share Kevin's opinion on MTA (postfix >> sendmail), it should be something decided by Server WG.

I suggest that the product release packages to be amended instead of fedora-release, list should be decided by WG and approved by FESCo to ensure consistency.

agreed The use of Suggests: as a mechanism to resolve ambiguous dependencies is approved. FESCo wants these Suggests: to live in the fedora-release and fedora-release-$EDITION subpackages rather than fedora-repos so that they can be made edition-specific if needed and so any such differences are maintained in the same repository. All such preferences must be approved by FESCo or the relevant Edition WG. (7, 0, 0)

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