`ultralytics 8.2.93` new SafeClass and SafeUnpickler classes (#16269)

Signed-off-by: UltralyticsAssistant <web@ultralytics.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

ultralytics/__init__.py

@@ -1,6 +1,6 @@
 # Ultralytics YOLO 🚀, AGPL-3.0 license
 
-__version__ = "8.2.92"
+__version__ = "8.2.93"
 
 
 import os

ultralytics/nn/tasks.py

@@ -1,6 +1,8 @@
 # Ultralytics YOLO 🚀, AGPL-3.0 license
 
 import contextlib
+import pickle
+import types
 from copy import deepcopy
 from pathlib import Path
 
@@ -750,7 +752,35 @@ def temporary_modules(modules=None, attributes=None):
                 del sys.modules[old]
 
 
-def torch_safe_load(weight):
+class SafeClass:
+    """A placeholder class to replace unknown classes during unpickling."""
+
+    def __init__(self, *args, **kwargs):
+        """Initialize SafeClass instance, ignoring all arguments."""
+        pass
+
+
+class SafeUnpickler(pickle.Unpickler):
+    """Custom Unpickler that replaces unknown classes with SafeClass."""
+
+    def find_class(self, module, name):
+        """Attempt to find a class, returning SafeClass if not among safe modules."""
+        safe_modules = (
+            "torch",
+            "collections",
+            "collections.abc",
+            "builtins",
+            "math",
+            "numpy",
+            # Add other modules considered safe
+        )
+        if module in safe_modules:
+            return super().find_class(module, name)
+        else:
+            return SafeClass
+
+
+def torch_safe_load(weight, safe_only=False):
     """
     Attempts to load a PyTorch model with the torch.load() function. If a ModuleNotFoundError is raised, it catches the
     error, logs a warning message, and attempts to install the missing module via the check_requirements() function.
@@ -758,9 +788,18 @@ def torch_safe_load(weight):
 
     Args:
         weight (str): The file path of the PyTorch model.
+        safe_only (bool): If True, replace unknown classes with SafeClass during loading.
+
+    Example:
+    ```python
+    from ultralytics.nn.tasks import torch_safe_load
+
+    ckpt, file = torch_safe_load("path/to/best.pt", safe_only=True)
+    ```
 
     Returns:
-        (dict): The loaded PyTorch model.
+        ckpt (dict): The loaded model checkpoint.
+        file (str): The loaded filename
     """
     from ultralytics.utils.downloads import attempt_download_asset
 
@@ -779,7 +818,15 @@ def torch_safe_load(weight):
                 "ultralytics.utils.loss.v10DetectLoss": "ultralytics.utils.loss.E2EDetectLoss",  # YOLOv10
             },
         ):
-            ckpt = torch.load(file, map_location="cpu")
+            if safe_only:
+                # Load via custom pickle module
+                safe_pickle = types.ModuleType("safe_pickle")
+                safe_pickle.Unpickler = SafeUnpickler
+                safe_pickle.load = lambda file_obj: SafeUnpickler(file_obj).load()
+                with open(file, "rb") as f:
+                    ckpt = torch.load(f, pickle_module=safe_pickle)
+            else:
+                ckpt = torch.load(file, map_location="cpu")
 
     except ModuleNotFoundError as e:  # e.name is missing module name
         if e.name == "models":
@@ -809,7 +856,7 @@ def torch_safe_load(weight):
         )
         ckpt = {"model": ckpt.model}
 
-    return ckpt, file  # load
+    return ckpt, file
 
 
 def attempt_load_weights(weights, device=None, inplace=True, fuse=False):