load module early during PythonPackage's sanity check step via sanity…

…_check_load_module (fixes #2745)

easybuild/easyblocks/generic/pythonpackage.py

@@ -790,6 +790,14 @@ def sanity_check_step(self, *args, **kwargs):
 
         success, fail_msg = True, ''
 
+        # load module early ourselves rather than letting parent sanity_check_step method do so,
+        # since custom actions taken below require that environment is set up properly already
+        # (especially when using --sanity-check-only)
+        if not self.sanity_check_module_loaded:
+            extension = self.is_extension or kwargs.get('extension', False)
+            extra_modules = kwargs.get('extra_modules', None)
+            self.fake_mod_data = self.sanity_check_load_module(extension=extension, extra_modules=extra_modules)
+
         # don't add user site directory to sys.path (equivalent to python -s)
         # see https://www.python.org/dev/peps/pep-0370/;
         # must be set here to ensure that it is defined when running sanity check for extensions,