Transitional (dummy) packages considered silly

[Stefano Zacchiroli]

On Thu, Sep 24, 2009 at 05:37:03PM +0200, Francesco P. Lovergine wrote:
> What about moving those packages under a transitional Section in the
> archive?  That would allow users to easily detect and remove them
> after dist-upgrades for instance, and it would also allow maintainers
> to mark proper transitional/dummy packages.

I was thinking along the same lines (which is a line of thought
orthogonal to an implementation of a Supersedes field: we can have
both).

So, let's focus on the user problem: how can we empower users to
recognize, with some certainty transactional packages to remove. Once we
have that, we can add a specific package manager command (a-la apt-get's
"autoremove" that in one step removes them).

I see various ways of enabling such recognition:

- Status quo: grepping for "transitional package" in package
  descriptions

- Archive section (i.e. Frankie's proposal): would ftp-master (Cc-ed)
  be willing to pursue that road?

- Debtags. Apparently there's already a tag "role::dummy" whose
  semantics seems to match "transitional package" (hence the name should
  probably be better?).

  However, if I check on my laptop I've about 20 transitional packages
  installed (detected using "status quo" above) and some empiric tests
  show that quite a lot of them do not have the "role::dummy" tag. This
  means that, at least currently, the debtags way is not really enough
  (or better: it looks to be sound, but not complete). I wonder why? Is
  it just missing tags or is there some more serious infrastructure
  problem? E.g.: is there a tag flow problem which "erases" tags from
  transitional package of past versions when the package got removed
  from the archive (but not necessarily from user machines?). Cc-ing
  debtags-devel for advices.

- A new debian/control field, e.g. "Transitional: yes"


I see no clear winner among the above choices. The proposed solution of
using archive sections, for instance, has the drawback that you renounce
to the "original" section and hence you will partly defeat user actions,
e.g., removing all installed packages belonging to a given section.

Debtags is clearly meant to solve this problem, but for transitional
packages I'd like to have a solution which is both sound and
complete. Only with such properties I'd be confident of integrating a
clean up actions which we can recommend doing, e.g., in release notes.

Thoughts?

Cheers.

-- 
Stefano Zacchiroli -o- PhD in Computer Science \ PostDoc @ Univ. Paris 7
zack@{upsilon.cc,pps.jussieu.fr,debian.org} -<>- http://upsilon.cc/zack/
Dietro un grande uomo c'è ..|  .  |. Et ne m'en veux pas si je te tutoie
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