Imported target "pybind11::headers" includes non-existent path

[hakonhagland]

Hi, I am using pybind11 2.11.1 on Ubuntu 23.10. I have installed the package pybind11-dev:

$ dpkg -L pybind11-dev
/.
/usr
/usr/include
/usr/include/pybind11
/usr/include/pybind11/attr.h
/usr/include/pybind11/buffer_info.h
/usr/include/pybind11/cast.h
/usr/include/pybind11/chrono.h
/usr/include/pybind11/common.h
/usr/include/pybind11/complex.h
/usr/include/pybind11/detail
/usr/include/pybind11/detail/class.h
/usr/include/pybind11/detail/common.h
/usr/include/pybind11/detail/descr.h
/usr/include/pybind11/detail/init.h
/usr/include/pybind11/detail/internals.h
/usr/include/pybind11/detail/type_caster_base.h
/usr/include/pybind11/detail/typeid.h
/usr/include/pybind11/eigen
/usr/include/pybind11/eigen/common.h
/usr/include/pybind11/eigen/matrix.h
/usr/include/pybind11/eigen/tensor.h
/usr/include/pybind11/eigen.h
/usr/include/pybind11/embed.h
/usr/include/pybind11/eval.h
/usr/include/pybind11/functional.h
/usr/include/pybind11/gil.h
/usr/include/pybind11/iostream.h
/usr/include/pybind11/numpy.h
/usr/include/pybind11/operators.h
/usr/include/pybind11/options.h
/usr/include/pybind11/pybind11.h
/usr/include/pybind11/pytypes.h
/usr/include/pybind11/stl
/usr/include/pybind11/stl/filesystem.h
/usr/include/pybind11/stl.h
/usr/include/pybind11/stl_bind.h
/usr/include/pybind11/type_caster_pyobject_ptr.h
/usr/lib
/usr/lib/cmake
/usr/lib/cmake/pybind11
/usr/lib/cmake/pybind11/FindPythonLibsNew.cmake
/usr/lib/cmake/pybind11/pybind11Common.cmake
/usr/lib/cmake/pybind11/pybind11Config.cmake
/usr/lib/cmake/pybind11/pybind11ConfigVersion.cmake
/usr/lib/cmake/pybind11/pybind11NewTools.cmake
/usr/lib/cmake/pybind11/pybind11Targets.cmake
/usr/lib/cmake/pybind11/pybind11Tools.cmake
/usr/share
/usr/share/doc
/usr/share/doc/pybind11-dev
/usr/share/doc/pybind11-dev/changelog.Debian.gz
/usr/share/doc/pybind11-dev/copyright
/usr/share/pkgconfig
/usr/share/pkgconfig/pybind11.pc

Note that, even if the list above says /usr/lib/cmake/pybind11/pybind11ConfigVersion.cmake the file is installed in /lib/cmake/pybind11/pybind11ConfigVersion.cmake since /lib is a symbolic link to /usr/lib on Ubuntu 23.10.

When I in a CMakeLists.txt run the command:

find_package(pybind11 2.2 CONFIG)

the file /lib/cmake/pybind11/pybind11Config.cmake will be executed and line 206 in that file:

get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)

I believe this is the same as this line in the GitHub repository:

pybind11/tools/pybind11Config.cmake.in

Line 201 in f33f6af

@PACKAGE_INIT@

The problem is that the above get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE) assumes that pybind11Config.cmake is located in /usr/lib/cmake/pybind11/pybind11Config.cmake and not in /lib/cmake/pybind11/pybind11Config.cmake. So PACKAGE_PREFIX_DIR will be set to "/" instead of "/usr" which will produce errors of the following type:

CMake Error in CMakeLists.txt:
  Imported target "pybind11::headers" includes non-existent path

    "/include"

[wjwwood]

I've run into this as well on Ubuntu 24.04, but strangely my colleagues didn't have this issue in a container and our CI doesn't run into this issue either (also using docker), so I'm not entirely sure why, but there seems to be another factor involved to trigger this issue, even though your explanation makes sense. I have the same kind of symlink on my machine, but so does my colleague and our CI:

$ ls -ls /lib
0 lrwxrwxrwx 1 root 7 Mar 30 17:04 /lib -> usr/lib

And here are my pybind11-dev and cmake versions:

$ dpkg -s pybind11-dev | grep Version
Version: 2.11.1-2

$ dpkg -s cmake | grep Version
Version: 3.28.3-1build7

[hakonhagland]

It seems to be related to the ordering of the PATH environment variable. I had the following PATH:

PATH=/bin:/usr/bin:/sbin:/usr/sbin

by moving the /bin entry from the beginning to the end like this:

export PATH=/usr/bin:/sbin:/usr/sbin:/bin

solved the problem for me.