Bug#1136233: fcl: FTBFS with libeigen3-dev 5.0 (major version transition)

[Anton Gladky]

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Hash: SHA512

Package: src:fcl
Version: 0.7.0-3
Severity: important
Tags: sid forky ftbfs
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

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

  https://debusine.debian.net/debian/developers-gladk-eigen3/artifact/3755617/raw/fcl_0.7.0-3_amd64-2026-05-08T08:27:49Z.build

Here is the most probably relevant part of the failing build log:
    ===========================================
[  1%] Building CXX object src/CMakeFiles/fcl.dir/broadphase/broadphase_bruteforce.cpp.o
cd /build/reproducible-path/fcl-0.7.0/obj-x86_64-linux-gnu/src && /usr/bin/c++ -Dfcl_EXPORTS -I/build/reproducible-path/fcl-0.7.0/obj-x86_64-linux-gnu/include -I/build/reproducible-path/fcl-0.7.0/include -isystem /usr/include/eigen3 -g -O2 -ffile-prefix-map=/build/reproducible-path/fcl-0.7.0=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC   -std=c++11 -W -Wall -Wextra -Wpedantic -fPIC -fvisibility=hidden -MD -MT src/CMakeFiles/fcl.dir/broadphase/broadphase_bruteforce.cpp.o -MF CMakeFiles/fcl.dir/broadphase/broadphase_bruteforce.cpp.o.d -o CMakeFiles/fcl.dir/broadphase/broadphase_bruteforce.cpp.o -c /build/reproducible-path/fcl-0.7.0/src/broadphase/broadphase_bruteforce.cpp
In file included from /usr/include/eigen3/Eigen/Core:22,
                 from /usr/include/eigen3/Eigen/Dense:1,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/common/types.h:46,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/math/bv/AABB.h:41,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/geometry/collision_geometry.h:43,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/narrowphase/collision_object.h:43,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_collision_manager.h:44,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_SSaP.h:42,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_SSaP-inl.h:41,
                 from /build/reproducible-path/fcl-0.7.0/src/broadphase/broadphase_SSaP.cpp:38:
/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.
      |  ^~~~~
In file included from /usr/include/eigen3/Eigen/Core:22,
                 from /usr/include/eigen3/Eigen/Dense:1,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/common/types.h:46,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/math/bv/AABB.h:41,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/geometry/collision_geometry.h:43,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/narrowphase/collision_object.h:43,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_collision_manager.h:44,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_bruteforce.h:42,
                 from /build/reproducible-path/fcl-0.7.0/include/fcl/broadphase/broadphase_bruteforce-inl.h:41,
                 from /build/reproducible-path/fcl-0.7.0/src/broadphase/broadphase_bruteforce.cpp:38:
/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.
      |  ^~~~~

    ===========================================
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
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