support non-diffusers hidream loras

Author: sayakpaul

src/diffusers/loaders/lora_conversion_utils.py

@@ -1704,3 +1704,11 @@ def get_alpha_scales(down_weight, key):
         converted_state_dict[f"transformer.{key}"] = converted_state_dict.pop(key)
 
     return converted_state_dict
+
+
+def _convert_non_diffusers_hidream_lora_to_diffusers(state_dict, non_diffusers_prefix="diffusion_model"):
+    if not all(k.startswith(non_diffusers_prefix) for k in state_dict):
+        raise ValueError("Invalid LoRA state dict for HiDream.")
+    converted_state_dict = {k.removeprefix(f"{non_diffusers_prefix}."): v for k, v in state_dict.items()}
+    converted_state_dict = {f"transformer.{k}": v for k, v in converted_state_dict.items()}
+    return converted_state_dict

src/diffusers/loaders/lora_pipeline.py

@@ -43,6 +43,7 @@
     _convert_hunyuan_video_lora_to_diffusers,
     _convert_kohya_flux_lora_to_diffusers,
     _convert_musubi_wan_lora_to_diffusers,
+    _convert_non_diffusers_hidream_lora_to_diffusers,
     _convert_non_diffusers_lora_to_diffusers,
     _convert_non_diffusers_lumina2_lora_to_diffusers,
     _convert_non_diffusers_wan_lora_to_diffusers,
@@ -5465,6 +5466,10 @@ def lora_state_dict(
             logger.warning(warn_msg)
             state_dict = {k: v for k, v in state_dict.items() if "dora_scale" not in k}
 
+        is_non_diffusers_format = any("diffusion_model" in k for k in state_dict)
+        if is_non_diffusers_format:
+            state_dict = _convert_non_diffusers_hidream_lora_to_diffusers(state_dict)
+
         return state_dict
 
     # Copied from diffusers.loaders.lora_pipeline.CogVideoXLoraLoaderMixin.load_lora_weights