Bug#1008489: dpkg: postinst should not warn about Debian's default (and soon only supported) filesystem layout

[Ansgar]

On Sat, 2022-04-09 at 11:01 -0700, Sean Whitton wrote:
> Okay I see.
> 
> To answer your question, then, the ctte has not even discussed the
> relevance of warnings to derivatives.

Well, the ctte has mostly discussed things in private. I have no idea
and it's not possible to comment on what the ctte might or might not
have discussed and might or might not have missed.

Impact on derivatives seems an obvious topic to me.

>   I can't speak for everyone, but I
> suspect that we would not consider this NMU to be in line with our
> existing decisions.

I look forward to seeing discussion on this or a summary of previous
private discussion results.

Ansgar

Bug#1008489: dpkg: postinst should not warn about Debian's default (and soon only supported) filesystem layout

[Sean Whitton]

Hello,

On Sat 09 Apr 2022 at 03:47pm +02, Ansgar wrote:

> On Sun, 2022-03-27 at 14:34 +0200, Ansgar wrote:
>> I think the warning emitted by dpkg's postinst script about Debian's
>> default filesystem layout is not appropriate and at least partially
>> misleading. Several other people agreed with this sentiment.
>
> To clarify due to misunderstanding that seem to have happened:
>
> - Merged-/usr is planned to become the only supported layout for Debian
> in the future, cf. [1].
>
> - Most Debian derivates will probably follow, some have already done so
> before Debian itself. So showing this warning in Debian derivates by
> default seems not a good solution; if a derivative wants this warning,
> they can patch it back in.

Okay I see.

To answer your question, then, the ctte has not even discussed the
relevance of warnings to derivatives.  I can't speak for everyone, but I
suspect that we would not consider this NMU to be in line with our
existing decisions.

-- 
Sean Whitton

Bug#1008489: dpkg: postinst should not warn about Debian's default (and soon only supported) filesystem layout

[Ansgar]

On Sat, 2022-04-09 at 16:28 +0200, Guillem Jover wrote:
> On Sat, 2022-04-09 at 15:47:17 +0200, Ansgar wrote:
> > On Sun, 2022-03-27 at 14:34 +0200, Ansgar wrote:
> > > I think the warning emitted by dpkg's postinst script about
> > > Debian's
> > > default filesystem layout is not appropriate and at least
> > > partially
> > > misleading. Several other people agreed with this sentiment.
> > 
> > To clarify due to misunderstanding that seem to have happened:
> > 
> > - Merged-/usr is planned to become the only supported layout for
> > Debian
> > in the future, cf. [1].
> 
> Perhaps I indeed misunderstood something, but this seemed pretty
> clear to me (from [T]:

I'm not sure what you mean by "this"? The decision to only support the
merged-/usr filesystem layout in the future?

>   - Because Debian 11 installations with the non-merged-/usr layout
>     already exist, all packages in Debian 12 should be installable
> onto a non-merged-/usr system along with their dependencies, and
> work correctly on the resulting system.

Packages in Debian 13 might no longer work correctly on legacy split-
/usr installations. Telling Debian 12/bookworm users to convert systems
to such a layout thus breaks their upgrade path to Debian 13 (including
partial upgrades) and should not be done.

[ Derivatives ]
> I'm not sure how this is a concern for Debian, TBH.

Any such problems will by default also happen on derivatives that don't
identify and patch affected packages. So I think an opt-in for this
warning is the better choice for derivatives that want to do so.

Ansgar

> 

Bug#1008489: dpkg: postinst should not warn about Debian's default (and soon only supported) filesystem layout

[Guillem Jover]

On Sat, 2022-04-09 at 15:47:17 +0200, Ansgar wrote:
> On Sun, 2022-03-27 at 14:34 +0200, Ansgar wrote:
> > I think the warning emitted by dpkg's postinst script about Debian's
> > default filesystem layout is not appropriate and at least partially
> > misleading. Several other people agreed with this sentiment.
> 
> To clarify due to misunderstanding that seem to have happened:
> 
> - Merged-/usr is planned to become the only supported layout for Debian
> in the future, cf. [1].

Perhaps I indeed misunderstood something, but this seemed pretty clear
to me (from [T]:

  - Because Debian 11 installations with the non-merged-/usr layout
already exist, all packages in Debian 12 should be installable onto a
non-merged-/usr system along with their dependencies, and work
correctly on the resulting system.

  - The same expectations apply to packages uploaded to testing/unstable
during the development cycle that will lead to Debian 12.

[T] 

> - Most Debian derivates will probably follow, some have already done so
> before Debian itself. So showing this warning in Debian derivates by
> default seems not a good solution; if a derivative wants this warning,
> they can patch it back in.

I'm not sure how this is a concern for Debian, TBH. If derivatives
show no interest in it and disable it, I'm happy to apply the same
upstream (as I've done for Ubuntu), I also monitor downstream patches
and try to merge stuff from them when relevant. If there'd be multiple
removals, I'd probably ponder making it opt-in or similar.

Regards,
Guillem

Bug#1008489: dpkg: postinst should not warn about Debian's default (and soon only supported) filesystem layout

[Ansgar]

On Sun, 2022-03-27 at 14:34 +0200, Ansgar wrote:
> I think the warning emitted by dpkg's postinst script about Debian's
> default filesystem layout is not appropriate and at least partially
> misleading. Several other people agreed with this sentiment.

To clarify due to misunderstanding that seem to have happened:

- Merged-/usr is planned to become the only supported layout for Debian
in the future, cf. [1].

- Most Debian derivates will probably follow, some have already done so
before Debian itself. So showing this warning in Debian derivates by
default seems not a good solution; if a derivative wants this warning,
they can patch it back in.

Ansgar

  [1]: https://bugs.debian.org/978636#178