Hi!

While preparing the Python 3.15 migration we realized that some Python packages
were shipping broken metadata directories, which leads to errors when trying to
import these directories with code running on Python 3.15.

To avoid shipping any additional broken directories, dh-python now throws an
error at build-time when the contents of the directories for two different
versions don't match.

Unfortunately, contourpy is one of the affected packages and fails to build with
the latest dh-python.

https://debusine.debian.net/debian/r-python-python3.15/artifact/5177968/

  W: dh_python3 fs:157: Paths differ: debian/python3-contourpy/usr/lib/python3.15/dist-packages/contourpy/util/  _build_config.py and debian/python3-contourpy/usr/lib/python3/dist-packages/contourpy/util/_build_config.py
  E: dh_python3 fs:173: Not everything in 'debian/python3-contourpy/usr/lib/python3.15/dist-packages/contourpy/util' was able to be merged into 'debian/python3-contourpy/usr/lib/python3/dist-packages/contourpy/util'.
  I: dh_python3 fs:180: Remaining files: debian/python3-contourpy/usr/lib/python3.15/dist-packages/contourpy/util/_build_config.py
  make: *** [debian/rules:7: binary-arch] Error 1
  dpkg-buildpackage: error: debian/rules binary-arch subprocess failed with exit status 2

The _build_config.py files indeed can't be merged. One alternative is to use the
new dh-python flag --allow-unmerged-dist-packages to allow this divergence (in
this case, it wouldn't lead to broken metadata directories, as they are not in
such a directory).  Another option would be to patch the code to not need this
file at all, as this seems mostly to be for debugging purposes.

This is a release critical issue, because we need to rebuild the package for the
3.15 transition.

We believe that the bug you reported is fixed in the latest version of
contourpy, 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 1152191@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Maximiliano Curia <maxy@debian.org> (supplier of updated contourpy 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: Tue, 27 Oct 2026 09:14:17 +0100
Source: contourpy
Architecture: source
Version: 1.3.3-3
Distribution: unstable
Urgency: medium
Maintainer: Debian Python Team <team+python@tracker.debian.org>
Changed-By: Maximiliano Curia <maxy@debian.org>
Closes: 1152191
Changes:
 contourpy (1.3.3-3) unstable; urgency=medium
 .
   * Team upload.
   * Allow unmerged _build_config.py (Closes: #1152191)
Checksums-Sha1:
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 e2ed6440ce1dde7a35cbeec5484aa972ab53f14a 3624 contourpy_1.3.3-3.debian.tar.xz
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