[Aptitude-devel] Bug#397728: aptitude should purge deleted packages at the end

[Manuel A. Fernandez Montecelo]

Hi,

2016-05-10 10:32 GMT+01:00 Vincent Lefevre <vincent at vinc17.net>:
> Hi,
>
> On 2016-05-04 20:20:59 +0100, Manuel A. Fernandez Montecelo wrote:
>> 2006-11-09 01:33 Vincent Lefevre:
>> > One may want to mark deleted packages as purge to get rid of obsolete
>> > configuration files. But some configuration files may be common to a
>> > package to be purged and a package to installed (this is the case when
>> > a package is renamed). To avoid losing the contents of these files
>> > (when the user has modified them), the actual purge should occur after
>> > installing all the packages.
>>
>> aptitude passes the information from a high-level point of view from
>> (lib)apt to dpkg, and they decide what to do between them depending on
>> complex sets of rules of who-depends-on-what.
>>
>> aptitude doesn't intervine directly in that process, so it cannot do
>> much, sorry.  Closing as +wontfix.
>>
>> I think that the cases that you mention has to be handled specially by
>> the package being renamed, to preserve the information from before.  If
>> old and new packages share config files, probably this is handled
>> specially by dpkg.
>
> You mean something like a dpkg transaction? Wouldn't this be a bug in
> dpkg, then? (But this bug was old, so that it may now be obsolete.)

Some of the specifics of configuration are covered in the Policy
manual, and I think that handling the config-files specially is
partially why there's separate steps for "prerm" and "postrm" scripts,
and why conffig files are removed last from a package (even after the
"postrm").  But maybe the current behaviour of the tools is not
covered properly, not sure.

In any case, since aptitude doesn't manage these specifics, and only
tells (lib)apt about its intentions at a higher level, it cannot do
much about this report.

Somewhat related, work is going to be started soon (not by me) to
rework parts of the communication and handling of actions between apt
and dpkg, so even the details of how it's done today can change in a
few months time (and I am quite sure that for the better, solving some
long-standing issues).


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