Bug#1031325: e2fsprogs 1.47.0 introduces a breaking change into Bookworm, breaking grub and making installations of Ubuntu and Debian releases via debootstrap impossible
Disclaimer:
Like everyone else except Sebastian who commented in this bug so far,
I am not a member of the release team.
Below is my attempt to give an overview of the situation,
feel free to amend/correct if anything is missing or wrong.
1. Image creation tools need special cases for older distibutions
Image creation tools that support installing older/other
distributions must be able to handle such differences in general
(e.g. debootstrap has code to handle apt-transport-https being
required in some older releases), and have to add the (trivial)
support for this difference.
Sebastian has already created #1031364 for the original vmdb2 problem.
2. How many packages are affected?
There are to at least two classes of affected packages:
- Bootloaders that can read (or even write) ext4.
- Image creation tools in bookworm that can create < bookworm images
For both classes it is unclear how many packages still require fixing.
This is a major unclear question.
3. Image creation versus target usage
The original #1030846 was from Debian Installer developers,
and everything discussed there is around image creation.
The original discussion was about installing bookworm from bookworm.
Daniel is discussing installing older/other distributions from bookworm.
Noone seems to have discussed on-target usage, e.g. when arguing in
#1030846 why there would not be a need for
Breaks: grub2-common (<< 2.06-8~)
in e2fsprogs.
The version of e2fsprogs currently in bookworm is in bullseye-backports,
if the version with the new default goes into bookworm and unchanged
into bullseye-backports it's pretty obvious how this could screw
on-target users ("target" might also be called "desktop" or "server")
when creating new bootable partitions.
4. e2fsprogs should add Breaks on non-fixed versions of packages
For e2fsprogs in bullseye-backports such Breaks might only be a reminder
that both the Breaks and the changed default should be reverted there,
but in bookworm it would ensure that users don't end up with an
incompatible combination of packages (e.g. if an older version of
grub or an image creation tool is pinned in apt).
5. Combination/Mix of packages from two adjacent Debian releases should work
A rule of thumb is that any combination/mix of packages permitted by the
package manager from two adjacent Debian releases should work whenever
reasonably possible, since this reduces problems for our users during an
upgrade, when using backports, or when temporarily going back to the
version of a package from the previous stable due to a regression.
The normal case (e.g. shared library linking) is that package
dependencies ensure that package managers will only permit working
combinations of packages.
Do we have any case where mixing bullseye and bookworm would not work
with Breaks on all unfixed versions of bootloaders and image creation tools?
6. Any data/experience from metadata_csum enabled by default in stretch?
There seems to have been a similar situation with metadata_csum being
enabled by default in stretch.
What data/experience exists about required fixes and problems from
that change?
7. It is late in the release cycle for such a change
The answer to point 2 is relevant whether it might be too late.
8. User documentation should document such incompatible changes
In whatever release this feature gets enabled by default,
a fresh bug against the release-notes pseudo-package with text
describing the incompatibility and possible workarounds should
be filed (Ted has already provided a draft text[1]).
9.There seems to be a similar situation with XFS bigtime
XFS is a less common filesystem, but what is discussed above
might also apply there.
10. Documentation for installing Debian from other distributions
Instructions for installing Debian from other distributions
need updating in any case.
Anything like [2] in the Bullseye Installation Guide will
be broken as soon as a different distribution changes the
default and needs updating, no matter what Debian does
in bookworm.
cu
Adrian
[1] https://lists.debian.org/debian-release/2023/02/msg00250.html
[2] https://www.debian.org/releases/stable/amd64/apds03.en.html
Reply to: