Merge pull request #3958 from Flamefire/20251014133801_new_pr_python

Move setting of `$PYTHON*` environment variables to `load_module` method in Python easyblock

Author: boegel

easybuild/easyblocks/p/python.py

@@ -495,8 +495,6 @@ def prepare_for_extensions(self):
         self.cfg['exts_defaultclass'] = "PythonPackage"
         self.cfg['exts_filter'] = EXTS_FILTER_PYTHON_PACKAGES
 
-        set_py_env_vars(self.log)
-
         # don't pass down any build/install options that may have been specified
         # 'make' options do not make sense for when building/installing Python libraries (usually via 'python setup.py')
         msg = "Unsetting '%s' easyconfig parameter before building/installing extensions: %s"
@@ -814,6 +812,16 @@ def _sanity_check_ebpythonprefixes(self):
             raise EasyBuildError("EasyBuilds sitecustomize.py did not add %s before %s to sys.path (%s)",
                                  temp_site_packages_path, base_site_packages_path, paths)
 
+    def load_module(self, *args, **kwargs):
+        """(Re)set environment variables after loading module file.
+
+        Required here to ensure the variables are also defined for stand-alone installations,
+        because the environment is reset to the initial environment right before loading the module.
+        """
+
+        super().load_module(*args, **kwargs)
+        set_py_env_vars(self.log)
+
     def sanity_check_step(self):
         """Custom sanity check for Python."""