Upgrade prepend failed warning to print_warning

Author: Flamefire

easybuild/tools/modules.py

@@ -1523,9 +1523,11 @@ def prepend_module_path(self, path, set_mod_paths=True, priority=None):
             modulepath = curr_module_paths(clean=False)
             path_idx = modulepath.index(path)
             if path_idx != 0:
-                self.log.warn("Path '%s' could not be prepended to $MODULEPATH. The following paths have a higher "
-                              "priority: %s'",
-                              path, "; ".join(modulepath[:path_idx]))
+                print_warning("Path '%s' could not be prepended to $MODULEPATH. "
+                              "The following paths are still in front of it: %s\n"
+                              "This can happen if paths were added via `module use` with a priority higher than %s",
+                              path, "; ".join(modulepath[:path_idx]), self.HIGH_PRIORITY,
+                              log=self.log)
             if set_mod_paths:
                 self.set_mod_paths()
 

test/framework/modules.py

@@ -630,6 +630,19 @@ def test_prepend_module_path(self):
             self.assertEqual(test_path_1, modulepath[1])
             self.assertEqual(test_path_0, modulepath[2])
 
+            # When prepend fails due to a higher priority path, a warning is shown
+            self.modtool.unuse(test_path_2)
+            self.modtool.prepend_module_path(test_path_0, priority=999999)
+            self.mock_stderr(True)
+            self.modtool.prepend_module_path(test_path_2)
+            stderr = self.get_stderr()
+            self.mock_stderr(False)
+            self.assertTrue('could not be prepended' in stderr)
+            modulepath = curr_module_paths()
+            self.assertEqual(test_path_0, modulepath[0])
+            self.assertEqual(test_path_2, modulepath[1])
+            self.assertEqual(test_path_1, modulepath[2])
+
     def test_ld_library_path(self):
         """Make sure LD_LIBRARY_PATH is what it should be when loaded multiple modules."""
         self.init_testmods()