Hi,

after this problem came up on irc I thought I would mention it to a
larger audience:

After upgrading to squeeze the dhcp client suddenly started to overwrite
/etc/resolv.conf again while before it was configured not to do so.

Looking into the cause we discovered that the problem is that
dhcp3-client is now a transitional package that pulls in
isc-dhcp-client. The new package expects its config files in /etc/dhcp
while the old had /etc/dhcp3/. The changes made to the old config no
longer affect the new client.

Which brings me to the subject of this mail:


Transitional packages with conffiles.

Wouldn't it be nice to detect when local configuration changes are lost
due to package migration?

Obviously it would be nice if the migration would also migrate the old
config to the new package but that isn't allways possible. In those
cases I think it would be nice to give a warning to the administrator
that he has to transition the config changes manually.

What I think might work is for the transitional dummy package to check
for modified conffiles and local config files in postinst. If such files
exist then a debconf warning should be shown. Transitional packages
depend on the new package so its postinst script has already run and
should have converted the old config where possible. So anything left
should be things that couldn't be handled automatically. If a better
test can be made for a package then by all means it should. But I think
as a generic test this should work.

What do you think?

MfG
Goswin


--
To UNSUBSCRIBE, email to debian-devel-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Archive: 87sjuoueyf.fsf@frosties.localnet">http://lists.debian.org/87sjuoueyf.fsf@frosties.localnet

On a somewhat related note:

If a package is manually installed, then replaced with a transitional
package, then apt should mark the transitional package's dependencies
as manually installed and the transitional package as automatically
installed. Otherwise, when one removes the transitional package
(which is supposedly 'safe' to do) the replacement package it depended
on becomes a candidate for autoremove.

Does apt do this? Is it even possible for it to recognise
transitional packages, without some unreliable heuristics?

Ben.

--
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
- Albert Camus


--
To UNSUBSCRIBE, email to debian-devel-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Archive: 20110316001025.GD2356@decadent.org.uk">http://lists.debian.org/20110316001025.GD2356@decadent.org.uk

Goswin von Brederlow writes ("Transitional packages with conffiles"):
> Looking into the cause we discovered that the problem is that
> dhcp3-client is now a transitional package that pulls in
> isc-dhcp-client. The new package expects its config files in /etc/dhcp
> while the old had /etc/dhcp3/. The changes made to the old config no
> longer affect the new client.

Well surely the question is: why are the files moved to a different
directory ? Why is the package renamed, even ? Do we need to be able
to co-install the old and new ISC DHCP clients ?!

Ian.


--
To UNSUBSCRIBE, email to debian-devel-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Archive: 19840.49857.610608.701669@chiark.greenend.org.uk"> http://lists.debian.org/19840.49857.610608.701669@chiark.greenend.org.uk

On Wed, Mar 16, 2011 at 02:01:37PM +0000, Ian Jackson wrote:
> Well surely the question is: why are the files moved to a different
> directory ? Why is the package renamed, even ? Do we need to be able
> to co-install the old and new ISC DHCP clients ?!

The original dhcp-client was version 2. dhcp3-client was version 3.
These used /etc/dhcp and /etc/dhcp3, IIRC. Someone realized that using
version numbers in the name was probably a bad idea, and that
dhcp-client was too generic a package name (there are many DHCP clients
in Debian). The idea was to abandon the old name and instead choose a
new name that was not so generic and at the same time, install the new,
version 4 client, using /etc/dhcp. Co-installability was not considered
important and thus the transitional package was created so that people
will have a working DHCP client.

If I'm wrong about any of this, I'm sure Andrew will correct me.

--
brian m. carlson / brian with sandals: Houston, Texas, US
+1 832 623 2791 | http://www.crustytoothpaste.net/~bmc | My opinion only
OpenPGP: RSA v4 4096b: 88AC E9B2 9196 305B A994 7552 F1BA 225C 0223 B187

Ian Jackson <ijackson@chiark.greenend.org.uk> writes:

> Goswin von Brederlow writes ("Transitional packages with conffiles"):
>> Looking into the cause we discovered that the problem is that
>> dhcp3-client is now a transitional package that pulls in
>> isc-dhcp-client. The new package expects its config files in /etc/dhcp
>> while the old had /etc/dhcp3/. The changes made to the old config no
>> longer affect the new client.
>
> Well surely the question is: why are the files moved to a different
> directory ? Why is the package renamed, even ? Do we need to be able
> to co-install the old and new ISC DHCP clients ?!
>
> Ian.

That is a question with a specific answere for every single transition
and irelevant to the question about what to do in general.

But if you must know I think in this case it is to correct the mistake
made with dhcp v3 where the major version was added to the dir
name. Using /etc/dhcp3 for a v4 dhcp seems wrong.

MfG
Goswin


--
To UNSUBSCRIBE, email to debian-devel-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Archive: 87fwql8mgy.fsf@frosties.localnet">http://lists.debian.org/87fwql8mgy.fsf@frosties.localnet