Tidy DenoiseLatentsInvocation.prep_control_data(...) and fix some type errors.

invokeai/app/invocations/denoise_latents.py

@@ -55,6 +55,7 @@ from invokeai.backend.stable_diffusion.diffusion.conditioning_data import (
 )
 from invokeai.backend.stable_diffusion.schedulers import SCHEDULER_MAP
 from invokeai.backend.util.devices import TorchDevice
+from invokeai.backend.util.hotfixes import ControlNetModel
 from invokeai.backend.util.mask import to_standard_float_mask
 from invokeai.backend.util.silence_warnings import SilenceWarnings
 
@@ -389,35 +390,35 @@ class DenoiseLatentsInvocation(BaseInvocation):
     @staticmethod
     def prep_control_data(
         context: InvocationContext,
-        control_input: Optional[Union[ControlField, List[ControlField]]],
+        control_input: ControlField | list[ControlField] | None,
         latents_shape: List[int],
         exit_stack: ExitStack,
         do_classifier_free_guidance: bool = True,
-    ) -> Optional[List[ControlNetData]]:
-        # Assuming fixed dimensional scaling of LATENT_SCALE_FACTOR.
-        control_height_resize = latents_shape[2] * LATENT_SCALE_FACTOR
-        control_width_resize = latents_shape[3] * LATENT_SCALE_FACTOR
-        if control_input is None:
-            control_list = None
-        elif isinstance(control_input, list) and len(control_input) == 0:
-            control_list = None
-        elif isinstance(control_input, ControlField):
+    ) -> list[ControlNetData] | None:
+        # Normalize control_input to a list.
+        control_list: list[ControlField]
+        if isinstance(control_input, ControlField):
             control_list = [control_input]
-        elif isinstance(control_input, list) and len(control_input) > 0 and isinstance(control_input[0], ControlField):
+        elif isinstance(control_input, list):
             control_list = control_input
+        elif control_input is None:
+            control_list = []
         else:
-            control_list = None
-        if control_list is None:
-            return None
-        # After above handling, any control that is not None should now be of type list[ControlField].
+            raise ValueError(f"Unexpected control_input type: {type(control_input)}")
 
-        # FIXME: add checks to skip entry if model or image is None
-        #        and if weight is None, populate with default 1.0?
-        controlnet_data = []
+        if len(control_list) == 0:
+            return None
+
+        # Assuming fixed dimensional scaling of LATENT_SCALE_FACTOR.
+        _, _, latent_height, latent_width = latents_shape
+        control_height_resize = latent_height * LATENT_SCALE_FACTOR
+        control_width_resize = latent_width * LATENT_SCALE_FACTOR
+
+        controlnet_data: list[ControlNetData] = []
         for control_info in control_list:
             control_model = exit_stack.enter_context(context.models.load(control_info.control_model))
+            assert isinstance(control_model, ControlNetModel)
 
-            # control_models.append(control_model)
             control_image_field = control_info.image
             input_image = context.images.get_pil(control_image_field.image_name)
             # self.image.image_type, self.image.image_name
@@ -438,7 +439,7 @@ class DenoiseLatentsInvocation(BaseInvocation):
                 resize_mode=control_info.resize_mode,
             )
             control_item = ControlNetData(
-                model=control_model,  # model object
+                model=control_model,
                 image_tensor=control_image,
                 weight=control_info.control_weight,
                 begin_step_percent=control_info.begin_step_percent,