[Debian-med-packaging] Bug#1136228: bustools: FTBFS with libeigen3-dev 5.0 (major version transition)

[Anton Gladky]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Package: src:bustools
Version: 0.45.1+dfsg-1
Severity: important
Tags: sid forky
User: debian-devel at lists.debian.org
Usertags: eigen3-5.0

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

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

  https://debusine.debian.net/debian/developers-gladk-eigen3/artifact/3754744/#L984-files

Here is the most probably relevant part of the failing build log:
    ------------------------------------------------------
- ------------------------------------------------------
[ 61%] Building CXX object src/CMakeFiles/bustools_core.dir/bustools_predict.cpp.o
cd /build/reproducible-path/bustools-0.45.1+dfsg/obj-x86_64-linux-gnu/src && /usr/bin/c++  -I/build/reproducible-path/bustools-0.45.1+dfsg/src -I/usr/include/eigen3 -I/usr/include/LBFGSpp -std=c++11 -g -O2 -ffile-prefix-map=/build/reproducible-path/bustools-0.45.1+dfsg=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wdate-time -D_FORTIFY_SOURCE=2 -g -g -flto -MD -MT src/CMakeFiles/bustools_core.dir/bustools_predict.cpp.o -MF CMakeFiles/bustools_core.dir/bustools_predict.cpp.o.d -o CMakeFiles/bustools_core.dir/bustools_predict.cpp.o -c /build/reproducible-path/bustools-0.45.1+dfsg/src/bustools_predict.cpp
In file included from /usr/include/eigen3/Eigen/Core:22,
                 from /build/reproducible-path/bustools-0.45.1+dfsg/src/bustools_predict.cpp:13:
/usr/include/eigen3/Eigen/src/Core/util/Macros.h:749:2: error: #error Eigen requires at least c++14 support.
  749 | #error Eigen requires at least c++14 support.
      |  ^~~~~
[ 65%] Building CXX object src/CMakeFiles/bustools_core.dir/bustools_project.cpp.o
cd /build/reproducible-path/bustools-0.45.1+dfsg/obj-x86_64-linux-gnu/src && /usr/bin/c++  -I/build/reproducible-path/bustools-0.45.1+dfsg/src -I/usr/include/eigen3 -I/usr/include/LBFGSpp -std=c++11 -g -O2 -ffile-prefix-map=/build/reproducible-path/bustools-0.45.1+dfsg=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wdate-time -D_FORTIFY_SOURCE=2 -g -g -flto -MD -MT src/CMakeFiles/bustools_core.dir/bustools_project.cpp.o -MF CMakeFiles/bustools_core.dir/bustools_project.cpp.o.d -o CMakeFiles/bustools_core.dir/bustools_project.cpp.o -c /build/reproducible-path/bustools-0.45.1+dfsg/src/bustools_project.cpp
[ 69%] Building CXX object src/CMakeFiles/bustools_core.dir/bustools_sort.cpp.o
cd /build/reproducible-path/bustools-0.45.1+dfsg/obj-x86_64-linux-gnu/src && /usr/bin/c++  -I/build/reproducible-path/bustools-0.45.1+dfsg/src -I/usr/include/eigen3 -I/usr/include/LBFGSpp -std=c++11 -g -O2 -ffile-prefix-map=/build/reproducible-path/bustools-0.45.1+dfsg=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wdate-time -D_FORTIFY_SOURCE=2 -g -g -flto -MD -MT src/CMakeFiles/bustools_core.dir/bustools_sort.cpp.o -MF CMakeFiles/bustools_core.dir/bustools_sort.cpp.o.d -o CMakeFiles/bustools_core.dir/bustools_sort.cpp.o -c /build/reproducible-path/bustools-0.45.1+dfsg/src/bustools_sort.cpp
In file included from /usr/include/eigen3/Eigen/Core:185:
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:209:37: error: ‘remove_const_t’ is not a member of ‘std’; did you mean ‘remove_const’? [-Wtemplate-body]
  209 | struct is_void : is_same<void, std::remove_const_t<T>> {};
      |                                     ^~~~~~~~~~~~~~
      |                                     remove_const
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:209:37: error: ‘remove_const_t’ is not a member of ‘std’; did you mean ‘remove_const’? [-Wtemplate-body]
  209 | struct is_void : is_same<void, std::remove_const_t<T>> {};
      |                                     ^~~~~~~~~~~~~~
      |                                     remove_const
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:209:52: error: template argument 2 is invalid [-Wtemplate-body]
  209 | struct is_void : is_same<void, std::remove_const_t<T>> {};
      |                                                    ^
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:209:53: error: expected ‘{’ before ‘>’ token
  209 | struct is_void : is_same<void, std::remove_const_t<T>> {};
      |                                                     ^~
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:305:27: error: ‘enable_if_t’ is not a member of ‘std’
  305 | struct array_size<T, std::enable_if_t<((T::SizeAtCompileTime & 0) == 0)>> {
      |                           ^~~~~~~~~~~
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:305:27: note: ‘std::enable_if_t’ is only available from C++14 onwards
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:305:27: error: ‘enable_if_t’ is not a member of ‘std’
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:305:27: note: ‘std::enable_if_t’ is only available from C++14 onwards
/usr/include/eigen3/Eigen/src/Core/util/Meta.h:305:71: error: type/value mismatch at argument 2 in template parameter list for ‘template<class T, class EnableIf> struct Eigen::internal::array_size’

    ------------------------------------------------------
- ------------------------------------------------------
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
-----BEGIN PGP SIGNATURE-----
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=GYgb
-----END PGP SIGNATURE-----