Fix LoRA compatibility issues. (#1320)

diffsynth/utils/lora/general.py

@@ -1,4 +1,4 @@
-import torch
+import torch, warnings
 
 
 class GeneralLoRALoader:
@@ -26,7 +26,11 @@ class GeneralLoRALoader:
                 keys.pop(0)
             keys.pop(-1)
             target_name = ".".join(keys)
-            lora_name_dict[target_name] = (key, key.replace(lora_B_key, lora_A_key))
+            # Alpha: Deprecated but retained for compatibility.
+            key_alpha = key.replace(lora_B_key + ".weight", "alpha").replace(lora_B_key + ".default.weight", "alpha")
+            if key_alpha == key or key_alpha not in lora_state_dict:
+                key_alpha = None
+            lora_name_dict[target_name] = (key, key.replace(lora_B_key, lora_A_key), key_alpha)
         return lora_name_dict
     
     
@@ -36,6 +40,10 @@ class GeneralLoRALoader:
         for name in name_dict:
             weight_up = state_dict[name_dict[name][0]]
             weight_down = state_dict[name_dict[name][1]]
+            if name_dict[name][2] is not None:
+                warnings.warn("Alpha detected in the LoRA file. This may be a LoRA model not trained by DiffSynth-Studio. To ensure compatibility, the LoRA weights will be converted to weight * alpha / rank.")
+                alpha = state_dict[name_dict[name][2]] / weight_down.shape[0]
+                weight_down = weight_down * alpha
             state_dict_[name + f".lora_B{suffix}"] = weight_up
             state_dict_[name + f".lora_A{suffix}"] = weight_down
         return state_dict_

examples/qwen_image/model_inference/Qwen-Image-Edit-2511-Lightning.py

@@ -18,7 +18,7 @@ lora = ModelConfig(
     model_id="lightx2v/Qwen-Image-Edit-2511-Lightning",
     origin_file_pattern="Qwen-Image-Edit-2511-Lightning-4steps-V1.0-bf16.safetensors"
 )
-pipe.load_lora(pipe.dit, lora, alpha=8/64)
+pipe.load_lora(pipe.dit, lora, alpha=1)
 pipe.scheduler = FlowMatchScheduler("Qwen-Image-Lightning")
 
 

examples/qwen_image/model_inference_low_vram/Qwen-Image-Edit-2511-Lightning.py

@@ -28,7 +28,7 @@ lora = ModelConfig(
     model_id="lightx2v/Qwen-Image-Edit-2511-Lightning",
     origin_file_pattern="Qwen-Image-Edit-2511-Lightning-4steps-V1.0-bf16.safetensors"
 )
-pipe.load_lora(pipe.dit, lora, alpha=8/64)
+pipe.load_lora(pipe.dit, lora, alpha=1)
 pipe.scheduler = FlowMatchScheduler("Qwen-Image-Lightning")
 
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "diffsynth"
-version = "2.0.4"
+version = "2.0.5"
 description = "Enjoy the magic of Diffusion models!"
 authors = [{name = "ModelScope Team"}]
 license = {text = "Apache-2.0"}