Installation seems to fail due to python as a normal user

I don't think I am doing something special.

While the installation returns success. the python stuff is not correctly installed.

I did reset the CMAKE_INSTALL_PREFIX to $HOME/dune_install and ran make install as a normal user:

-- Installing: /home/mblatt/dune_install/share/bash-completion/completions/dunecontrol
Installing python package (Debug)
CMake Warning at /home/mblatt/src/dune/opm-2.10/dune-common/cmake/modules/DuneExecuteProcess.cmake:76 (message):
  python package installation failed - ignored

  Run command:/usr/bin/cmake;--build;.;--target;install_python;--config;Debug

  Return code: 2

  Output:

  gmake[1]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  betreten

  gmake[2]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  betreten

  gmake[3]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  betreten

  gmake[4]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  betreten

  gmake[4]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  verlassen

  gmake[4]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  betreten

  Installing the python package at
  /home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug/python/.
  (location --user)

  error: externally-managed-environment

  

  × This environment is externally managed

  ╰─> To install Python packages system-wide, try apt install

      python3-xyz, where xyz is the package you are trying to
      install.
      
      If you wish to install a non-Debian-packaged Python package,
      create a virtual environment using python3 -m venv path/to/venv.
      Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
      sure you have python3-full installed.
      
      If you wish to install a non-Debian packaged Python application,
      it may be easiest to use pipx install xyz, which will manage a
      virtual environment for you. Make sure you have pipx installed.
      
      See /usr/share/doc/python3.11/README.venv for more information.

  

  note: If you believe this is a mistake, please contact your Python
  installation or OS distribution provider.  You can override this, at the
  risk of breaking your Python installation or OS, by passing
  --break-system-packages.

  hint: See PEP 668 for the detailed specification.

  gmake[4]: ***
  [python/CMakeFiles/install_python_package_017119b47aa3e31d2f1458e7ae21943a.dir/build.make:71:
  python/CMakeFiles/install_python_package_017119b47aa3e31d2f1458e7ae21943a]
  Fehler 1

  gmake[4]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  verlassen

  gmake[3]: *** [CMakeFiles/Makefile2:5414:
  python/CMakeFiles/install_python_package_017119b47aa3e31d2f1458e7ae21943a.dir/all]
  Fehler 2

  gmake[3]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  verlassen

  gmake[2]: *** [CMakeFiles/Makefile2:2040:
  CMakeFiles/install_python.dir/rule] Fehler 2

  gmake[2]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  verlassen

  gmake[1]: *** [Makefile:621: install_python] Fehler 2

  gmake[1]: Verzeichnis
  „/home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug“ wird
  verlassen

Call Stack (most recent call first):
  python/cmake_install.cmake:55 (dune_execute_process)
  cmake_install.cmake:96 (include)


Installing wheel for python package at /home/mblatt/src/dune/opm-2.10/dune-common/opm-parallel-debug/python/. into /home/mblatt/dune_install/share/dune/wheelhouse...

Interestingly the return code of the install command is 0, like success.