Attempt to handle lack of __dict__ on TypeVar in Python 3.12

synchronicity/synchronizer.py

@@ -243,12 +243,17 @@ def _translate_scalar_out(self, obj, interface):
             interface = Interface.BLOCKING
 
         # If it's an internal object, translate it to the external interface
-        if inspect.isclass(obj) or isinstance(obj, typing.TypeVar):  # TODO: functions?
+        if inspect.isclass(obj):  # TODO: functions?
             cls_dct = obj.__dict__
             if self._wrapped_attr in cls_dct:
                 return cls_dct[self._wrapped_attr][interface]
             else:
                 return obj
+        elif isinstance(obj, typing.TypeVar):
+            if hasattr(obj, self._wrapped_attr):
+                return getattr(obj, self._wrapped_attr)[interface]
+            else:
+                return obj
         else:
             cls_dct = obj.__class__.__dict__
             if self._wrapped_attr in cls_dct:
@@ -620,16 +625,22 @@ def _wrap(
         # It wraps the object, and caches the wrapped object
 
         # Get the list of existing interfaces
-        if self._wrapped_attr not in obj.__dict__:
-            if isinstance(obj.__dict__, dict):
-                # This works for instances
-                obj.__dict__.setdefault(self._wrapped_attr, {})
-            else:
-                # This works for classes & functions
+        if hasattr(obj, "__dict__"):
+            if self._wrapped_attr not in obj.__dict__:
+                if isinstance(obj.__dict__, dict):
+                    # This works for instances
+                    obj.__dict__.setdefault(self._wrapped_attr, {})
+                else:
+                    # This works for classes & functions
+                    setattr(obj, self._wrapped_attr, {})
+            interfaces = obj.__dict__[self._wrapped_attr]
+        else:
+            # e.g., TypeVar in Python>=3.12
+            if not hasattr(obj, self._wrapped_attr):
                 setattr(obj, self._wrapped_attr, {})
+            interfaces = getattr(obj, self._wrapped_attr)
 
         # If this is already wrapped, return the existing interface
-        interfaces = obj.__dict__[self._wrapped_attr]
         if interface in interfaces:
             if self._multiwrap_warning:
                 warnings.warn(f"Object {obj} is already wrapped, but getting wrapped again")
@@ -674,8 +685,9 @@ def _wrap_type_var(self, obj, interface, name, target_module):
         new_obj.__dict__[SYNCHRONIZER_ATTR] = self
         new_obj.__dict__[TARGET_INTERFACE_ATTR] = interface
         new_obj.__module__ = target_module
-        obj.__dict__.setdefault(self._wrapped_attr, {})
-        obj.__dict__[self._wrapped_attr][interface] = new_obj
+        if not hasattr(obj, self._wrapped_attr):
+            setattr(obj, self._wrapped_attr, {})
+        getattr(obj, self._wrapped_attr)[interface] = new_obj
         return new_obj
 
     def nowrap(self, obj):