On 8 Sep 1996, Kai Henningsen wrote:
[EMAIL PROTECTED] (Guy Maor) wrote on 05.09.96 in [EMAIL PROTECTED]:
Is the essentialness of a package a sufficient condition for using
pre-depends?
The difference in functionality between depends and pre-depends, as I
understand it, are that a pre-depends guarantees that your package won't
even be *unpacked* unless the pre-depends is already completely installed.
On the other hand, a depends only guarantees that the other package will
be completely installed before *configuration* of your package starts.
That's correct.
Pre-depends and essentialness are different things. The first prevents
a package from existing in an unconfigured state (when dependencies
might not be satisfied). The second prevents a package from being
removed.
In both cases the intent is the same: there should *always* be a
working version of the package installed. So very few packages should
have one without the other. A quick script gives:
adduser ess but not pre-dep and has dep
at pre-dep but not ess
libc5 pre-dep but not ess
modules pre-dep but not ess
ncurses3.0 ess but not pre-dep and has dep
perl pre-dep but not ess
All but two of these should have both or neither. The only that look
correct are perl, because base includes a stripped version, and libc5,
which requires a working ld.so, but might be removed in favor of
libc6.
Note that packages in base are *not* automatically essential. The key
point here is that the system is unusable, not hard to use.
Guy
