fix(diffusers): forward original config for single files

Assisted-by: Codex:gpt-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/python/diffusers/backend.py

@@ -35,6 +35,7 @@ from diffusers_dynamic_loader import (
     get_available_pipelines,
     load_diffusers_pipeline,
 )
+from load_options import single_file_load_kwargs
 
 # Import specific items still needed for special cases and safety checker
 from diffusers import DiffusionPipeline, ControlNetModel
@@ -479,6 +480,9 @@ class BackendServicer(backend_pb2_grpc.BackendServicer):
 
         # Build kwargs for dynamic loading
         load_kwargs = {"torch_dtype": torchType}
+        load_kwargs.update(
+            single_file_load_kwargs(request.OriginalConfigFile, from_single_file)
+        )
 
         # Add variant if not loading from single file
         if not from_single_file and variant:

backend/python/diffusers/load_options.py

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: MIT
+
+
+def single_file_load_kwargs(original_config_file: str, from_single_file: bool) -> dict:
+    if from_single_file and original_config_file:
+        return {"original_config_file": original_config_file}
+    return {}

backend/python/diffusers/test_load_options.py

@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: MIT
+
+import unittest
+
+from backend.python.diffusers.load_options import single_file_load_kwargs
+
+
+class SingleFileLoadKwargsTest(unittest.TestCase):
+    def test_includes_original_config_for_single_file(self):
+        self.assertEqual(
+            single_file_load_kwargs("configs/v1-inference.yaml", True),
+            {"original_config_file": "configs/v1-inference.yaml"},
+        )
+
+    def test_omits_original_config_for_pretrained_model(self):
+        self.assertEqual(
+            single_file_load_kwargs("configs/v1-inference.yaml", False),
+            {},
+        )
+
+    def test_omits_empty_original_config(self):
+        self.assertEqual(single_file_load_kwargs("", True), {})
+
+
+if __name__ == "__main__":
+    unittest.main()