add deprecation warning in model

src/graphnet/models/model.py

@@ -64,9 +64,13 @@ def load_state_dict(
 
         # DEPRECATION UTILITY: REMOVE AT 2.0 LAUNCH
         # See https://github.com/graphnet-team/graphnet/issues/647
-        state_dict = rename_state_dict_entries(
+        state_dict, state_dict_altered = rename_state_dict_entries(
             state_dict=state_dict, old_phrase="_gnn", new_phrase="backbone"
         )
+        if state_dict_altered:
+            self.warn(
+                "DeprecationWarning: State dicts with `_gnn` entries will be deprecated in GraphNeT 2.0"
+            )
         return super().load_state_dict(state_dict, **kargs)
 
     @classmethod

src/graphnet/utilities/deprecation_tools.py

@@ -1,12 +1,12 @@
 """Utility functions for handling deprecation transitions."""
-from typing import Dict
+from typing import Dict, Tuple
 from copy import deepcopy
 from torch import Tensor
 
 
 def rename_state_dict_entries(
     state_dict: Dict[str, Tensor], old_phrase: str, new_phrase: str
-) -> Dict[str, Tensor]:
+) -> Tuple[Dict[str, Tensor], bool]:
     """Replace `old_phrase` in state dict fields with `new_phrase`.
 
     Returned state dict is a deepcopy of the input.
@@ -23,8 +23,11 @@ def rename_state_dict_entries(
     new_state_dict = deepcopy(state_dict)
 
     # Replace old entries in copy
+    state_dict_altered = False
     for key in state_dict.keys():
         if old_phrase in key:
             new_key = key.replace(old_phrase, new_phrase)
             new_state_dict[new_key] = new_state_dict.pop(key)
-    return new_state_dict
+            state_dict_altered = True
+
+    return new_state_dict, state_dict_altered