RetopoFlow 4 broken in Blender 4.4 beta

[jlampel]

When using RF in Blender 4.4 beta, many of the tools do not work, the overlays do not draw, and the following error appears:

LAUNCHING IN NEW AREA 0,164
Exception ignored in: <function RFCore_Operator.__del__ at 0x0000021E322B9800>
Traceback (most recent call last):
  File "C:\Users\Jonathan\AppData\Roaming\Blender Foundation\Blender\4.4\scripts\addons\retopoflow_4\retopoflow\rfcore.py", line 536, in __del__
    print(f'RFCore_Operator.__del__!!! {getattr(self, "is_running", None)}')
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Jonathan\Desktop\blender-4.4.0-beta\blender-4.4.0-beta\4.4\scripts\modules\bpy_types.py", line 936, in __getattribute__
    properties = _StructRNA.path_resolve(self, "properties")
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ReferenceError: StructRNA of type RFCore_Operator has been removed
RuntimeError: could not create instance of RETOPOFLOW_OT_core to call callback function 'execute'
Error: Python: RuntimeError: could not create instance of RETOPOFLOW_OT_core to call callback function 'execute'
Location: C:\Users\Jonathan\Desktop\blender-4.4.0-beta\blender-4.4.0-beta\4.4\scripts\modules\bpy\ops.py:109
Traceback (most recent call last):
  File "C:\Users\Jonathan\AppData\Roaming\Blender Foundation\Blender\4.4\scripts\addons\retopoflow_4\retopoflow\rfcore.py", line 363, in handle_draw_cursor
    bpy.ops.retopoflow.core()
  File "C:\Users\Jonathan\Desktop\blender-4.4.0-beta\blender-4.4.0-beta\4.4\scripts\modules\bpy\ops.py", line 109, in __call__
    ret = _op_call(self.idname_py(), kw)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Error: Python: RuntimeError: could not create instance of RETOPOFLOW_OT_core to call callback function 'execute'
Location: C:\Users\Jonathan\Desktop\blender-4.4.0-beta\blender-4.4.0-beta\4.4\scripts\modules\bpy\ops.py:109

The breaking changes that might be relevant to us are the changes to Blender type subclasses and polyline drawing.... but sometimes there are surprises that are not documented 😅