#672945 dpkg should support moving a conffile between packages

Package:
dpkg
Source:
dpkg
Description:
Debian package management system
Submitter:
Josh Triplett
Date:
2026-06-09 01:29:05 UTC
Severity:
wishlist
#672945#3
Date:
2012-05-14 21:20:06 UTC
From:
To:
netbase 5.0 drops /etc/init.d/networking; thank you for that.  However,
dpkg does not automatically remove conffiles (even unmodified conffiles)
when upgrading to a version of the package that does not include the
conffile.  Thus, upgrading from previous versions of netbase to netbase
5.0 leaves /etc/init.d/networking around.

Normally, I'd suggest using dpkg-maintscript-helper rm_conffile, but I
don't know if that'll work correctly when the user has already upgraded
ifupdown.  I don't think a standard procedure exists for moving
conffiles between packages; sysvinit and the newly split-out bootlogd
have the same problem with bootlogd's init scripts.  (Also, I don't
quite see how it works to upgrade ifupdown without upgrading netbase,
since ifupdown and older netbase both ship /etc/init.d/networking and no
conflicts or replaces exists between those versions.)

- Josh Triplett
#672945#8
Date:
2012-05-14 22:12:51 UTC
From:
To:
reassign 672945 dpkg
severity 672945 wishlist
retitle 672945 dpkg should support moving a conffile between packages
thanks
This is true, as long as you do not have ifupdown installed (which is
very unusual).

The consensus on #debian-devel is that nobody should waste their time
to fix this, but I will be happy to accept a patch.
This post documents a possible solution:
https://lists.debian.org/debian-devel/2012/02/msg00254.html .

As suggested by #debian-devel, I am reassigning this bug to dpkg.
#672945#21
Date:
2012-05-14 23:13:16 UTC
From:
To:
Granted.

Going by that post, would something like the following in the configure
section of the postinst work?

if dpkg --compare-versions "$2" lt 5.1 ; then
    if [ "$(dpkg-query --showformat='${Status}' -W ifupdown)" = "unknown ok not-installed" ] &&
       [ -e /etc/init.d/networking ] &&
       [ "$(md5sum < /etc/init.d/networking)" = "3bb6d34b6a295bb01142d9a667de4b0d -" ] ; then
        rm -f /etc/init.d/networking
    fi
fi

The version comparison assumes the change goes into version 5.1 of
netbase.

Personally, I'd love to see this bug fixed in dpkg by just removing
unmodified conffiles that disappear from a package, but nonetheless
having a well-supported mechanism to move conffiles between packages
would help.

- Josh Triplett
#672945#26
Date:
2012-05-14 23:16:31 UTC
From:
To:
Not quite, this would be too much easy.
At least, we need to check in preinst for the *actual* md5sum of the
version of /etc/init.d/networking installed by the old package, set a
flag file (maybe containing this md5sum) and then delete the file in
postinst if needed.
#672945#31
Date:
2012-05-15 04:43:58 UTC
From:
To:
If you mean to handle upgrades from versions of netbase that shipped a
different version of /etc/init.d/networking, note that
/etc/init.d/networking has not changed since squeeze, so the squeeze
netbase would have exactly the same md5sum; I checked. :)  And since
Debian doesn't support upgrades that skip a release, an unmodified
version of /etc/init.d/networking can only have the one md5sum that I
listed.  So, the code I provided will work for any supported upgrade
scenario.

(I agree that the general case for arbitrary packages requires the
approach you suggest, but in this particular case the simpler version
with a single hardcoded md5sum will work just fine.)

- Josh Triplett