[Aptitude-devel] Bug#787663: aptitude forgets/clears manually set auto-installed-flags in several situations

[Manuel A. Fernandez Montecelo]

Control: tags -1 + wontfix
Control: close -1


2016-02-29 05:15 Christoph Anton Mitterer:
>On Sun, 2016-02-28 at 17:29 +0000, Manuel A. Fernandez Montecelo wrote:
>> On the other hand, if I understood correctly, if nothing depends on
>> krb5-k5tls on your system, you shouldn't have it marked as
>> automatically
>> installed.
>
>Why not?

Because marking a package auto means to tell aptitude "remove it from my
system as soon as it's not needed".

  http://aptitude.alioth.debian.org/doc/en/ch02s02s06.html

  It works like this: when you install a package, aptitude will
  automatically install any other packages on which it depends. These
  packages are marked as having been “automatically installed”; aptitude
  will monitor them and remove them when they are no longer depended
  upon by any manually installed package [10] . They will appear in the
  preview as “packages being removed because they are no longer used.”

  As with any automatic process, there is a potential for things to go
  haywire. For instance, even if a package was automatically installed
  to start with, it might turn out to be useful in its own right. You
  can cancel the “automatic” flag at any time by pressing m; if the
  package is already being removed, you can use Package → Install (+) to
  cancel the removal and clear the “automatic” flag.


aptitude was not doing a very good job at it, and because of that people
filed dozens of bugs over the years (most of which have been fixed in
recent versions) complaining that aptitude was not removing unwanted
garbage from their system, or not doing it quick enough (within the same
session).

I seems that you were relying on some of these wrong behaviours that
have now been fixed.


>It's a handy way to flag packages which I have just installed because
>of something else (which however lacks a recommends or so)...
>e.g. mkvtoolnix-gui used to not be recommended by mkvtoolnix, but I
>installed the former only because of the later...
>Or it can be used to scheduled packages for removal, but not doing it
>right now.

You can mark packages for removal and exit aptitude without removing
immediately, but this will not fly long and other tools of the system
might decide to remove it.

If you want to keep a list of packages to-be-eventually-removed, you can
use user-tags.


>> In fact, installing krb5-k5tls in my system and marking it as
>> automatically installed, aptitude attempts to remove it immediately
>> --
>> which is the right thing to do.
>Sure.. but I don't think it's the right thing to remove the flag if I
>manually set it.
>Human is smarter than the machine... if he wants it he should get it.

aptitude doesn't remove the flag now, but the package altogether, which
is what the human requested (and what aptitude failed to do until
recently).

If human doesn't want the package removed, human should revisit what the
machine is asked to do.


Cheers.
-- 
Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>