Set scheduler in args only if img2img class has it

ia_webui_controlnet.py

@@ -1,6 +1,8 @@
 import copy
 import importlib
+import inspect
 import os
+from dataclasses import fields, is_dataclass
 
 import modules.scripts as scripts
 from modules import paths, shared
@@ -149,6 +151,33 @@ def clear_controlnet_cache(cnet, input_scripts):
                 script.clear_control_model_cache()
 
 
+def get_init_params(cls):
+    """
+    Returns a list of parameter names for the __init__ method of a given class.
+    Works for both dataclasses and regular classes.
+
+    Args:
+        cls (type): The class to inspect.
+
+    Returns:
+        list: A list of parameter names for the __init__ method.
+    """
+    if is_dataclass(cls):
+        # For dataclasses
+        return [field.name for field in fields(cls)]
+    elif inspect.isclass(cls):
+        # For regular classes
+        try:
+            signature = inspect.signature(cls.__init__)
+        except (ValueError, TypeError):
+            # Handle classes with no __init__ method
+            return []
+        # Exclude "self" and return the rest of the parameters
+        return [param.name for param in signature.parameters.values() if param.name != "self"]
+    else:
+        raise TypeError(f"Expected a class, got {type(cls).__name__}")
+
+
 def get_sd_img2img_processing(init_image, mask_image, prompt, n_prompt, sampler_id, ddim_steps, cfg_scale, strength, seed,
                               mask_blur=4, fill_mode=1):
     """Get StableDiffusionProcessingImg2Img instance
@@ -187,7 +216,6 @@ def get_sd_img2img_processing(init_image, mask_image, prompt, n_prompt, sampler_
         negative_prompt=n_prompt,
         seed=seed,
         sampler_name=sampler_id,
-        scheduler="Automatic",
         batch_size=1,
         n_iter=1,
         steps=ddim_steps,
@@ -199,6 +227,8 @@ def get_sd_img2img_processing(init_image, mask_image, prompt, n_prompt, sampler_
         do_not_save_samples=True,
         do_not_save_grid=True,
     )
+    if "scheduler" in get_init_params(StableDiffusionProcessingImg2Img):
+        sd_img2img_args["scheduler"] = "Automatic"
 
     p = StableDiffusionProcessingImg2Img(**sd_img2img_args)