Bug#495954: slapd: Upgrade to Lenny failed: libldap_r-2.3.so.0 missing

[Daniel Burrows <dburrows@debian.org>]

On Sat, Aug 23, 2008 at 02:41:02PM -0700, Steve Langasek <vorlon@debian.org> was heard to say:
> Other comments:
> As for the claim that this is an apt bug instead of an aptitude bug:
> 
> >   I think it pretty much confirms this: particularly the fact that
> > aptitude believes that it's installing the required new package.  That
> > means that at some point, the lower layers in apt are turning this into
> > two dpkg runs, and breaking them up in a way that doesn't respect
> > dependencies.
> 
> dpkg can never be called to do both removals and installs of packages in a
> single invocation; the most it can do is --auto-deconfigure while
> installing.  So this is not a case of apt "splitting" the commands wrong
> when passing them to dpkg, it looks to me like apt is being asked to do the
> wrong thing if it even has the *option* of ordering the package removal
> before the upgrade.

  A very brief reply:

  My understanding of the apt library has always been that the frontend
describes a consistent state of the "world", and that apt is responsible
for computing and executing a series of dpkg calls that will place the
world (or at least the package system) in that state.  In this case, for
instance, aptitude tells apt to install the new openldap and libldap,
and to remove the old libldap.  Under my interpretation, apt should
recognize that it needs to install the new ldap and upgrade slapd
before it removes the old one.

  From what you're saying, it sounds like this is an incorrect
interpretation and aptitude should be handling the install ordering
itself.  No matter where it is, though, this is the last email I will
read or send for a week.  If aptitude needs to be fixed, go ahead and
do it.

    Later,
  Daniel