Dear Maintainer,

your package depends on libeigen3-dev. The upstream released a
new major version of this mathematical library, 5.0.0. Some
basic information about new features and changes in this version
can be found here:

https://libeigen.gitlab.io/releases/5.0/

This is a major version change and may require code changes in packages
depending on eigen3. The key breaking changes include:

  - Minimum required C++ standard is now C++14
  - Changes in the build system integration
  - Some API name changes

sopt FTBFS with libeigen3-dev 5.0.1. The full build log is available at:

https://debusine.debian.net/debian/developers-gladk-eigen3/artifact/3761812/

Here is the most probably relevant part of the failing build log:
    ===========================================
common_mpi_catch_main.cc.o -c /build/reproducible-path/sopt-5.0.1+dfsg/cpp/tests/common_mpi_catch_main.cc
In file included from /build/reproducible-path/sopt-5.0.1+dfsg/cpp/sopt/../sopt/wavelets/wavelets.h:5,
                 from /build/reproducible-path/sopt-5.0.1+dfsg/cpp/sopt/wavelets/wavelets.cc:1:
/build/reproducible-path/sopt-5.0.1+dfsg/cpp/sopt/../sopt/types.h:7:10: fatal error: Eigen/Core: No such file or directory
    7 | #include <Eigen/Core>
      |          ^~~~~~~~~~~~
compilation terminated.
make[3]: *** [cpp/sopt/CMakeFiles/sopt.dir/build.make:96: cpp/sopt/CMakeFiles/sopt.dir/wavelets/wavelets.cc.o] Error 1
make[3]: *** Waiting for unfinished jobs....

    ===========================================
libeigen3-dev_5.0.1-1 is available in experimental.

When this package version lands into unstable (probably at the beginning
of June 2026), this bug will be increased in severity to serious.

Thanks,

Anton

Dear maintainers,

eigen3 5.0 (libeigen3-dev 5.0) is now in unstable, so these FTBFS bugs are
release-critical.  I am therefore raising their severity to serious.

Regards,

Anton