The PR #577 used hasattr(o, i) to skip uninitialized slots, but hasattr() swallows all

  AttributeErrors — including those from __getattr__. This made objects with a broken __getattr__
  (like the Bad test class) appear to have zero accessible slots rather than failing the strategy.

  The fix uses object.__getattribute__() to check each slot directly, which bypasses __getattr__
  entirely. For classes that do define __getattr__, if a slot isn't initialized via the descriptor,
   we fall back to the normal getattr() — letting __getattr__ either provide a value or raise
  (propagating the failure). This correctly handles:

  - Uninitialized slots (no __getattr__): skipped gracefully, empty dict is valid
  - Partially initialized slots: only initialized ones included
  - Broken __getattr__: error propagates, object becomes unprocessed

Author: seperman

deepdiff/deephash.py

@@ -280,6 +280,27 @@ def __getitem__(self, obj: Any, extract_index: Optional[int] = 0) -> Any:
                              use_enum_value=self.use_enum_value,
                              ignore_numeric_type_changes=self.ignore_numeric_type_changes)
 
+    @staticmethod
+    def _get_slots_dict(obj: Any) -> Dict[str, Any]:
+        """Get a dict of initialized slot attributes.
+
+        Uses object.__getattribute__ to check each slot directly, bypassing
+        __getattr__. For uninitialized slots on classes that define __getattr__,
+        falls back to getattr — letting it raise if the object is truly broken.
+        """
+        result = {}
+        has_getattr = hasattr(type(obj), '__getattr__')
+        for slot in obj.__slots__:
+            try:
+                result[slot] = object.__getattribute__(obj, slot)
+            except AttributeError:
+                if has_getattr:
+                    # The slot isn't initialized, but the class defines __getattr__.
+                    # Try the normal getattr to let __getattr__ provide a value or
+                    # raise — if it raises, we propagate to fail the strategy.
+                    result[slot] = getattr(obj, slot)
+        return result
+
     @staticmethod
     def _getitem(hashes: Dict[Any, Any], obj: Any, extract_index: Optional[int] = 0,
                  use_enum_value: bool = False, ignore_numeric_type_changes: bool = False) -> Any:
@@ -415,7 +436,7 @@ def _prep_obj(self, obj: Any, parent: str, parents_ids: frozenset = EMPTY_FROZEN
             obj_to_dict_strategies.append(lambda o: o.__dict__)
 
         if hasattr(obj, "__slots__"):
-            obj_to_dict_strategies.append(lambda o: {i: getattr(o, i) for i in o.__slots__ if hasattr(o, i)})
+            obj_to_dict_strategies.append(lambda o: DeepHash._get_slots_dict(o))
         else:
             import inspect
             obj_to_dict_strategies.append(lambda o: dict(inspect.getmembers(o, lambda m: not inspect.isroutine(m))))