`buildenv` EasyBlock incorrectly sets `PATH` on `--module-only` and crashes on `--sanity-check-only`

[Thyre]

See #4037 (comment) and #4037 (comment)

A --module-only rebuild sets:

  >> generating module file @ /data/EasyBuild-develop/modules/all/MPI/GCC/14.3.0/OpenMPI/5.0.8/buildenv/default.lua
== comparing module file with backup /data/EasyBuild-develop/modules/all/MPI/GCC/14.3.0/OpenMPI/5.0.8/buildenv/default.bak_20260112165059_1226463; diff is:
--- /data/EasyBuild-develop/modules/all/MPI/GCC/14.3.0/OpenMPI/5.0.8/buildenv/default.bak_20260112165059_1226463
+++ /data/EasyBuild-develop/modules/all/MPI/GCC/14.3.0/OpenMPI/5.0.8/buildenv/default.lua
@@ -31,12 +31,12 @@
 depends_on("ScaLAPACK/2.2.2-fb")

 prepend_path("CMAKE_PREFIX_PATH", root)
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/gcc_wrapper")
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/ld.gold_wrapper")
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/gxx_wrapper")
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/ld.bfd_wrapper")
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/ld_wrapper")
-prepend_path("PATH", "/data/EasyBuild-develop/software/buildenv/default-foss-2025b/bin/rpath_wrappers/gfortran_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/gcc_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/ld.gold_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/gxx_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/ld.bfd_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/ld_wrapper")
+prepend_path("PATH", "/data/EasyBuild-develop/build/buildenv/default/foss-2025b/rpath_wrappers/gfortran_wrapper")

i.e. uses the build directory instead of the installation directory.

With --sanity-check-only, the build instead crashes entirely, even after re-building without --module-only:

EasyBuild crashed! Please consider reporting a bug, this should not happen...

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 861, in <module>
    main_with_hooks()
    ~~~~~~~~~~~~~~~^^
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 846, in main_with_hooks
    exit_code: EasyBuildExit = main(args=args, prepared_cfg_data=(init_session_state, eb_go, cfg_settings))
                               ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 797, in main
    is_successful = process_eb_args(orig_paths, eb_go, cfg_settings, modtool, testing, init_session_state,
                                    hooks, do_build)
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 613, in process_eb_args
    ecs_with_res = build_and_install_software(
        ordered_ecs, init_session_state, exit_on_failure=exit_on_failure, testing=testing)
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 226, in build_and_install_software
    raise error
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/main.py", line 180, in build_and_install_software
    (ec_res['success'], app_log, err_msg, err_code) = build_and_install_one(ec, init_env)
                                                      ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/framework/easyblock.py", line 5109, in build_and_install_one
    result = app.run_all_steps(run_test_cases=run_test_cases)
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/framework/easyblock.py", line 4922, in run_all_steps
    self.run_step(step_name, step_methods)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/framework/easyblock.py", line 4763, in run_step
    current_method()
    ~~~~~~~~~~~~~~^^
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/easyblocks/generic/bundle.py", line 478, in sanity_check_step
    fake_mod_data = self.load_fake_module(purge=True)
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/framework/easyblock.py", line 1902, in load_fake_module
    fake_mod_path = self.make_module_step(fake=True)
  File "/data/EasyBuild/lib/python3.14/site-packages/easybuild/easyblocks/generic/buildenv.py", line 119, in make_module_step
    wrappers_dir = os.path.join(self.rpath_wrappers_dir, RPATH_WRAPPERS_SUBDIR)
  File "<frozen posixpath>", line 77, in join
TypeError: expected str, bytes or os.PathLike object, not NoneType

---

To reproduce:

eb --rebuild buildenv-default-foss-2025b.eb
eb --rebuild buildenv-default-foss-2025b.eb --module-only
eb --rebuild buildenv-default-foss-2025b.eb
eb --rebuild buildenv-default-foss-2025b.eb --sanity-check-only

[Thyre]

On module-only, we skip install_step. buildenv sets rpath_wrappers_dir to the final install directory during install_step, so it's stuck on self.builddir, set in prepare_step.

On sanity-check-only, the same thing happens. However, now we also skip prepare_step, therefore not setting rpath_wrappers_dir at all.

With a manual print in make_module_step:

ERROR: Installation of buildenv-default-foss-2025b.eb failed: None, /data/EasyBuild-develop/build/buildenv/default/foss-2025b

[boegel]

@ocaisa Can you take a look at this one?

[Flamefire]

The crash should be fixed by #4068
We usually don't create a module in --sanity-check-only but the Bundle easyblock did

However the --module-only part still needs fixing