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Re: [RFC] Changing APT to pre-depend on ${shlibs:Depends}



On Do, 2011-04-28 at 08:41 -0700, Steve Langasek wrote:
> On Wed, Apr 27, 2011 at 01:46:50PM -0500, Peter Samuelson wrote:
> > [Eugene V. Lyubimkin]
> > > Second, why the APT's ability to upgrade is broken under these
> > > conditions? Unless I'm missing something, the upgrade cannot be
> > > started in the middle of another upgrade [1].
> 
> > > [1] If we count the situation for resuming broken upgrade, there is a
> > > some chance you'll have to call dpkg manually or some hacks
> > > to proceed anyway.
> 
> > Not always.  There are states dpkg goes through that 'apt-get install'
> > can "recover" from on its own.  You don't always have to go to dpkg.
> 
> > Also, what if apt wants to call one of its auxilliary binaries during
> > the install/upgrade?  I imagine it's not implemented that way _now_,
> > but a Pre-Depends would make such a thing a lot safer if they want it.
> > (Same is true if they want to dlopen a library during the install, but
> > that's somewhat less likely.)
> 
> "We might some day later change the way apt works for upgrades" is not an
> argument for adding a pre-dependency now.
> 
But that we do want to prevent a broken APT -- when using the common
"dpkg -i ...; apt-get install -f" idiom (where ... is APT) -- certainly
is an argument. 

Also, as always, if you change something, change it as early in the
release cycle as possible.

We do have the following arguments:
        + prevents issues when using dpkg -i

Neutral facts are:
        ~ highly unlikely to introduce new issues in APT
        ~ we already do this in APT (not much changes for us)
        
The counter argument seems to be 
        - we do not protect the user from removing APT with dpkg
                => counter argument: dpkg -i is common, dpkg -R is not
                (see Raphaël's email)
        - there are other package managers
                => counter argument: No other package manager has as few
                dependencies as APT and as high priority.
                
So practically spoken, we are at something like +0.5 for the change
based on the arguments. Based on votes, we're currently at +1.

-1 jackyf@debian.org
+1 peter@p12n.org
+1 hertzog@debian.org
-2 kalnischkies+debian@gmail.com
+2 jak@debian.org
 0 mvo@debian.org
------------------
+1 total (maximum 9)

I counted members of the APT team twice, and only obvious votes, not
unclear comments.

Maybe we could also change dpkg to treat Depends like Pre-Depends (do
not even unpack) for --install, as dpkg already has --unpack for
unpacking only? But that is likely to brake more things (such as > 0)
than changing those Depends to Pre-Depends.

-- 
Julian Andres Klode  - Debian Developer, Ubuntu Member

See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/.



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