python3-towncrier has an undeclared file conflict.  This may result in
an unpack error from dpkg.

The files
 * /usr/lib/python3/dist-packages/towncrier/__init__.py
 * /usr/lib/python3/dist-packages/towncrier/__main__.py
 * /usr/lib/python3/dist-packages/towncrier/_builder.py
 * /usr/lib/python3/dist-packages/towncrier/_git.py
 * /usr/lib/python3/dist-packages/towncrier/_project.py
 * /usr/lib/python3/dist-packages/towncrier/_settings/__init__.py
 * /usr/lib/python3/dist-packages/towncrier/_settings/fragment_types.py
 * /usr/lib/python3/dist-packages/towncrier/_settings/load.py
 * /usr/lib/python3/dist-packages/towncrier/_shell.py
 * /usr/lib/python3/dist-packages/towncrier/_writer.py
 * /usr/lib/python3/dist-packages/towncrier/build.py
 * /usr/lib/python3/dist-packages/towncrier/check.py
 * /usr/lib/python3/dist-packages/towncrier/click_default_group.py
 * /usr/lib/python3/dist-packages/towncrier/create.py
 * /usr/lib/python3/dist-packages/towncrier/templates/default.md
 * /usr/lib/python3/dist-packages/towncrier/templates/default.rst
 * /usr/lib/python3/dist-packages/towncrier/templates/hr-between-versions.rst
 * /usr/lib/python3/dist-packages/towncrier/templates/single-file-no-bullets.rst
 * /usr/lib/python3/dist-packages/towncrier/test/__init__.py
 * /usr/lib/python3/dist-packages/towncrier/test/helpers.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_build.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_builder.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_check.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_create.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_format.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_git.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_project.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_settings.py
 * /usr/lib/python3/dist-packages/towncrier/test/test_write.py
are contained in the packages
 * python3-towncrier/25.8.0-2 as present in unstable
 * towncrier/24.8.0-2 as present in trixie|forky

These packages can be unpacked concurrently, because there is no
relevant Replaces or Conflicts relation.  Attempting to unpack these
packages concurrently results in an unpack error from dpkg, because none
of the packages installs a diversion for the affected files.

Kind regards

Helmut Grohne

Control: retitle -1 python3-towncrier: Undeclared file conflict with earlier 'towncrier' versions
Control: tags -1 + confirmed pending

This is because ‘python3-towncrier’ currently declares only a “Breaks”
relationship, which allows unpacking over the older ‘towncrier’ versions.
This relationship is incorrect.

The correction is to tighten the relationship to “Conflicts”, that signals
to ‘dpkg’ it must not unpack over the existing package. (As described in
Policy §7.4, “Conflicting binary packages - "Conflicts"”.)

That correction is now implemented, and will be part of the next package
release.

Please make sure that upload will be a source only upload, so the
fix for #1143428 can actually migrate.

Thanks,
Chris

Note that Conflicts rarely is the right solution. It imposes
restrictions on upgrades that cause trouble to dist-upgrades and should
best be avoided. In simple cases such as file moves (as is happening
here), the weaker form of a combination of Breaks and Replaces should be
used.

I observe that more and more people resort to declaring Conflicts in
response to my bug reports. Do you have an idea how I could improve the
reports or how we could improve the documentation (e.g. policy) to
better direct people towards Breaks+Replaces? My mail explicitly
mentions Replaces already.

Helmut

Thanks for asking how to improve this.

I think, if you want a better solution to become the norm, then we need to
make that better solution the *one obvious* solution that is found.

When a maintainer learns (through a bug report, or otherwise) that a
“Breaks: package (<= older-version)” is insufficient? That maintainer will
go looking in places like the Policy document.

That IMO means that the desired solution must be found right there, or
anywhere the maintainer is likely to go looking for a solution.

Currently, my quick reading of the Policy document led to the comparison of
“Breaks” versus “Conflicts”; that was apparently the most salient
difference, so that's what I reached for.

So, to more precisely answer your query (how you might more successfully
ask people to correct the binary package dependencies): the Policy section
to read is §7.6 “Overwriting files and replacing packages - "Replaces"”.

That section did not show up immediately when I went looking for the most
obvious fix. I think, if you want people to read it, you'll need to direct
them to Policy §7.6, specifically.

Thanks again, for giving attention to this and for seeking how to improve
effectiveness.

Thank you to Helmut G. for directing me to the better solution, described
in Policy §7.6: this should instead be a “Breaks” + “Replaces”
relationship.

    Package: python3-towncrier
    Breaks:
        towncrier (<= 24.8.0-2)
    Replaces:
        towncrier (<= 24.8.0-2)

In commit 6571efa52b54a98bba857689483e03b28c742f0a, this is now implemented
<URL: https://salsa.debian.org/bignose/pkg-towncrier/-/commit/6571efa52b54a98bba857689483e03b28c742f0a>
and will be part of the next release.

Hi Ben,

* Ben Finney <bignose@debian.org> [2026-08-29 08:31]:

Can you please upload this new release soonish?

Currently towncrier is marked for removal from testing on September 19.
and with it over 2000 other packages as can be seen on:

https://tracker.debian.org/pkg/towncrier

Also please make sure to upload only a source package without binary
packages so the package can migrate to testing.

Thanks!

Jochen

We believe that the bug you reported is fixed in the latest version of
towncrier, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1145012@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Ben Finney <bignose@debian.org> (supplier of updated towncrier package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Mon, 31 Aug 2026 10:05:49 +1000
Source: towncrier
Architecture: source
Version: 25.8.0-3
Distribution: unstable
Urgency: medium
Maintainer: Ben Finney <bignose@debian.org>
Changed-By: Ben Finney <bignose@debian.org>
Closes: 1145012
Changes:
 towncrier (25.8.0-3) unstable; urgency=medium
 .
   * debian/control:
     * Declare “Breaks” + “Replaces” relationship to avoid file conflicts.
       Closes: bug#1145012. Thanks to Helmut Grohne for the report.
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 454da3c69758d19af3c304c3af1e38e52fb3a6c5 16056 towncrier_25.8.0-3.debian.tar.xz
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 97aebb94b133fe85cb38720c54242cda 16056 devel optional towncrier_25.8.0-3.debian.tar.xz
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