apt and packages order on the command line

[Gabriel Moreau <Gabriel.Moreau@hmg.inpg.fr>]

Hello,

Please apologize for my poor English... I wish I post on the good 
mailing list too.

I make all my test on a PC i386 Debian Sarge uptodate.

I found a funny thing about apt. I try to install tree packages with
apt-get and the result depend on the order of the packages on the
command line.

I try theses two command

 apt-get install at cron-apt exim4-daemon-light
 apt-get install exim4-daemon-light at cron-apt

Before doing this, you have to purge your system from exim4 configuration

 apt-get --purge remove exim4-config

In the first case, apt-get try to install

 at courier-authdaemon courier-base cron-apt exim4-base exim4-config
exim4-daemon-light mailx

In the second case, you will only have

 at cron-apt exim4-base exim4-config exim4-daemon-light mailx

So, the list of install package will be different. In the first case, 
where 'at' is before 'exim', you will have a 'courier' package leave on 
your system.

I do not see any dependence with 'apt-cache show', just a 
mail-transport-agent for at. So I try the third command, always purging 
exim4 before...

 apt-get install at cron-apt

Now, the installed packages will be

 at courier-authdaemon courier-base courier-mta cron-apt mailx

The courier mail transport agent will be installed, not exim. I thought 
it was exim4 the default mail agent in Debian ? The funny thing is that 
all my computer have exim4, not courier.

It's the first time that I see that the order package has an influence 
on the result with apt-get. I never read something about that on 
documentation.

This strange behavior of apt-get is a bad news for me because i would 
like to install package automatically from cfengine. But it is not the 
cfengine philosophy to write  the package on the command line with a 
certain order.

I give you now the result of the command line, locale are in French but 
i think everybody can read it.


tech7meylan:/home/gabriel# apt-get --purge remove exim4-config
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances... Fait
Les paquets suivants seront ENLEVÉS :
  at* cron-apt* exim4-base* exim4-config* exim4-daemon-light* mailx*


tech7meylan:/home/gabriel# apt-get install exim4-daemon-light at cron-apt
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances... Fait
Les paquets supplémentaires suivants seront installés :
  exim4-base exim4-config mailx
Paquets suggérés :
  eximon4 exim4-doc-html exim4-doc-info gnutls-bin libmail-spf-query-perl
Les NOUVEAUX paquets suivants seront installés :
  at cron-apt exim4-base exim4-config exim4-daemon-light mailx


tech7meylan:/home/gabriel# apt-get install at cron-apt exim4-daemon-light
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances... Fait
Les paquets supplémentaires suivants seront installés :
  courier-authdaemon courier-base exim4-base exim4-config mailx
Paquets suggérés :
  eximon4 exim4-doc-html exim4-doc-info gnutls-bin libmail-spf-query-perl
Les NOUVEAUX paquets suivants seront installés :
  at courier-authdaemon courier-base cron-apt exim4-base exim4-config
exim4-daemon-light mailx


tech7meylan:/home/gabriel# apt-get install at cron-apt
Lecture des listes de paquets... Fait
Construction de l'arbre des dépendances... Fait
Les paquets supplémentaires suivants seront installés :
  courier-authdaemon courier-base courier-mta mailx
Paquets suggérés :
  courier-doc courier-filter-perl
Les NOUVEAUX paquets suivants seront installés :
  at courier-authdaemon courier-base courier-mta cron-apt mailx


Thank you for your attention

gaby
--
Gabriel Moreau - IR CNRS
LEGI - Laboratoire des Ecoulements Geophysiques et Industriels
BP53, 38041 Grenoble Cedex, France       http://www.legi.hmg.inpg.fr
mailto:Gabriel.Moreau@hmg.inpg.fr   tel:+33.476.825.015   fax:++.271