bug#19296: [PATCH] Package archives now have priorities.

[Jorgen Schaefer <forcer@forcix.cx>]

On Sun, 7 Dec 2014 06:19:29 -0800 (PST)
Drew Adams <drew.adams@oracle.com> wrote:

> Why is that good?  Why should MELPA be given a lower priority?

MELPA provides unstable versions of packages. To provide stable
versions of packages, there is the "MELPA Stable" repository (among
others, including GNU ELPA). As not all packages in MELPA unstable
are available in MELPA stable, users have to add both to their
archives list to get access to all packages. But due to the way MELPA
assigns version numbers, the unstable versions will always override
stable versions, even when both are available.

This patch will allow a setup that takes the newest version of a
package from GNU ELPA, MELPA stable or Marmalade, and only if there is
no version available from any of these repositories, take the one
available from MELPA unstable. No jumping through hoops required.

The current solution to this is to add all packages available from
non-MELPA unstable to `package-pinned-packages'.

The facility of priorities for repositories is widely available in
other package managers, e.g. in Debian's apt (see apt_preferences(5)).

You can read more about the problems with MELPA's versioning system
here:

http://blog.jorgenschaefer.de/2014/06/the-sorry-state-of-emacs-lisp-package.html

I hope I could answer your questions.

Regards,
Jorgen