#1112916 flann: FTBFS with CMake 4

#1112916#5
Date:
2025-08-31 22:53:47 UTC
From:
To:
Dear maintainer,

During a test rebuild for CMake 4, flann failed to rebuild.

Log Summary:
-------------------------------------------------------------------------------
[...]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=77y7
-----END PGP SIGNATURE-----

dpkg-source: warning: cannot verify inline signature for ./flann_1.9.2+dfsg-2.dsc: no acceptable signature found
dpkg-source: info: extracting flann in /build/reproducible-path/flann-1.9.2+dfsg
dpkg-source: info: unpacking flann_1.9.2+dfsg.orig.tar.xz
dpkg-source: info: unpacking flann_1.9.2+dfsg-2.debian.tar.xz
dpkg-source: info: using patch list from debian/patches/series
dpkg-source: info: applying 0001-Updated-fix-cmake-hdf5.patch
dpkg-source: info: applying 0004-Add-empty-date-in-manual-to-make-build-reproducible.patch
dpkg-source: info: applying 0005-Fix-lz4-missing-from-flann.pc-Requires-line.patch

Check disk space
----------------

Sufficient free space for build

User Environment
----------------

APT_CONFIG=/var/lib/sbuild/apt.conf
HOME=/sbuild-nonexistent
LANG=C.UTF-8
LC_ALL=C.UTF-8
LOGNAME=sbuild
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
SHELL=/bin/sh
USER=sbuild

dpkg-buildpackage
-----------------

Command: dpkg-buildpackage --sanitize-env -us -uc -b
dpkg-buildpackage: info: source package flann
dpkg-buildpackage: info: source version 1.9.2+dfsg-2
dpkg-buildpackage: info: source distribution unstable
dpkg-buildpackage: info: source changed by Jochen Sprickerhof <jspricke@debian.org>
 dpkg-source --before-build .
dpkg-buildpackage: info: host architecture arm64
 debian/rules clean
dh clean
   dh_clean
 debian/rules binary
dh binary
   dh_update_autotools_config
   dh_autoreconf
   debian/rules override_dh_auto_configure
make[1]: Entering directory '/build/reproducible-path/flann-1.9.2+dfsg'
dh_auto_configure -- -DBUILD_MATLAB_BINDINGS=OFF -DBUILD_PYTHON_BINDINGS=OFF -DUSE_MPI=ON -DUSE_OPENMP=ON -DBUILD_TESTS=ON -DLIB_SUFFIX="/aarch64-linux-gnu" -DBUILD_CUDA_LIB=OFF
	cd obj-aarch64-linux-gnu && DEB_PYTHON_INSTALL_LAYOUT=deb PKG_CONFIG=/usr/bin/pkg-config cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=None -DCMAKE_INSTALL_SYSCONFDIR=/etc -DCMAKE_INSTALL_LOCALSTATEDIR=/var -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY=ON -DCMAKE_FIND_USE_PACKAGE_REGISTRY=OFF -DCMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY=ON -DFETCHCONTENT_FULLY_DISCONNECTED=ON -DCMAKE_INSTALL_RUNSTATEDIR=/run -DCMAKE_SKIP_INSTALL_ALL_DEPENDENCY=ON "-GUnix Makefiles" -DCMAKE_VERBOSE_MAKEFILE=ON -DCMAKE_INSTALL_LIBDIR=lib/aarch64-linux-gnu -DBUILD_MATLAB_BINDINGS=OFF -DBUILD_PYTHON_BINDINGS=OFF -DUSE_MPI=ON -DUSE_OPENMP=ON -DBUILD_TESTS=ON -DLIB_SUFFIX=/aarch64-linux-gnu -DBUILD_CUDA_LIB=OFF ..
CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.5 has been removed from CMake.

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.

  Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.
-------------------------------------------------------------------------------

The above is just how the build ends and not necessarily the most relevant part.
If required, the full build log is available here (for the next 30 days):
https://debusine.debian.net/artifact/2392423/

The most likely cause of build failures is the removed backwards compatibility for
CMake versions earlier than 3.5. You can find additional information in my
debian-devel announcement:

https://lists.debian.org/debian-devel/2025/04/msg00310.html

About the archive rebuild: The build was made on debusine.debian.net,
using sbuild.

You can find the build task here:
https://debusine.debian.net/work-request/152884/

If this is really a bug in one of the build-depends, please use
reassign and affects, so that this is still visible in the BTS web
page for this package.

Thanks,
Timo

#1112916#12
Date:
2025-09-01 11:51:32 UTC
From:
To:
I have downgraded the bug to non-RC severity temporarily and reverted
CMake in unstable to version 3.31.6. I plan to re-upgrade in about a
month's time. I realize that despite my April announcement, the upload
to unstable came rather surprising, and I don't want to cause
unnecessary pain.

Also, the build log URL has an unfortunate mistake. The correct URL
should include the workspace, i.e.,

https://debusine.debian.net/debian/developers/artifact/XXXX

CMake 4 will also be available in experimental again, so it can be
used to verify that the bug is fixed.

Cheers
Timo