Bug#800769: pbuilder: conffiles not removed

[Wouter Verhelst]

On Sun, Oct 11, 2015 at 03:49:31PM +0000, Mattia Rizzolo wrote:
> On Sun, Oct 11, 2015 at 11:03:09AM +0200, Wouter Verhelst wrote:
> > The only way to hand a file (any file) over to another package is by way of
> > 'Replaces:', *without* the Conflicts: and Provides:.
> > 
> > Since this is a single packaga version, you could put the file in pbuilder-uml
> > and have that 'Replaces: pbuilder (= 0.217)', that way the possible damage in
> > case you have other (accidental) file conflicts would be limited.
> 
> Though this way if a person install pbuilder 0.217, then removes it the
> conffile would stay there, and that's the whole point of the bug.
> I agree the Replaces is needed, but I don't see it as being enough to
> deal with this... :(

So these are the possible interactions that I can think of:

- If it's removed without --purge, the conffile stays, true,
  but that's what the user asked for.
- If it's removed without --purge, and later pbuilder-uml is installed,
  the Replaces: header takes care of taking over the config file.
- If it's removed with --purge without installing pbuilder-uml, the
  conffile is still registered to pbuilder and will be removed along
  with the rest of the package.
- If it's removed with --purge after installing pbuilder-uml, the
  Replaces: header should ensure it won't be removed (though you might
  want to test that to be sure).
- New versions of pbuilder should check in their postinst (with
  dpkg-query) when they're upgrading from 0.217 or purging what the
  status of pbuilder-uml is. If it's installed or at config-files with a
  version that has the Replaces: header, then pbuilder should not touch
  it. If not, it should remove the file.

Did I miss any other use case?

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