Re: how to find why packages are automatically installed?
On Tue, Feb 24, 2009 at 5:32 AM, Daniel Burrows <dburrows@debian.org> wrote:
> On Mon, Feb 23, 2009 at 09:54:00AM -0800, "Michael M. Moore" <michael@writemoore.net> was heard to say:
>>>> The thing is I was planning on keeping gdm, though I guess I could
>>>> switch to xdm, or do without a display manager. But gdm, according
>>>> to aptitude, shouldn't require nautilus. It shouldn't even require
>>>> gnome-session, just one of gnome-session | x-session-manager |
>>>> x-window-manager | x-terminal-emulator. I have Openbox and xterm
>>>> installed, so I should be covered there, right?
>>>
>>> Then you need to remove gnome-session and replace it with something
>>> else.
>>
>> That gets to the heart of my confusion about how this works, because I
>> didn't *need* a replacement for gnome-session -- I already had packages
>> installed that satisfied that requirement.
>
> aptitude conservatively assumes that if A depends on B, that you might
> want B because of A. That's true even if the same dependency could be
> satisfied by another package -- otherwise aptitude would be in the
> business of guessing which alternative not to delete. :-)
>
To expand upon this, I believe the OP's situation is some behaviour I've
also seen, which seemed odd until I thought about it and couldn't actually
come up with a better way:
Assume you have aptitude set not to install recommends automatically.
1) Install package A, which recommends package B.
2) Install package C, which depends on package B.
B is installed and marked as automatic.
3) Uninstall package C.
It seems like B should be uninstalled, because the package which pulled it
in automatically has been removed. Actually though, it's kept because
there's still a packages recommending it.
It's annoying because it means that install and purge are not symmetric
operations, and I initially felt (in the case where aptitude is set no to
install recommends) that aptitude should remove packages marked as
automatically installed when no packages depend on them. However, this
could have the effect of causing half the system to be uninstalled when
aptitude is changed from 'install recommends' to 'ignore recommends', so I
presume that's why it's not done. For all I know there's a setting
somewhere to make it do this :P.
Nye
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