Added support to load model config from Metadata. (#399)

* Implement GGUF metadata extraction function

Added function to extract metadata from GGUF files.

* Updated the GGUF model loading and patching classes to include metadata handling.

* Clean up return logic for extra metadata

This should be more future proof in case we need to return other attributes in the future. Possible breaking change for anyone using `gguf_sd_loader` directly either way, though.

---------

Co-authored-by: City <125218114+city96@users.noreply.github.com>

loader.py

@@ -48,7 +48,26 @@ def get_list_field(reader, field_name, field_type):
     else:
         raise TypeError(f"Unknown field type {field_type}")
 
-def gguf_sd_loader(path, handle_prefix="model.diffusion_model.", return_arch=False, is_text_model=False):
+def get_gguf_metadata(reader):
+    """Extract all simple metadata fields like safetensors"""
+    metadata = {}
+    for field_name in reader.fields:
+        try:
+            field = reader.get_field(field_name)
+            if len(field.types) == 1:  # Simple scalar fields only
+                if field.types[0] == gguf.GGUFValueType.STRING:
+                    metadata[field_name] = str(field.parts[field.data[-1]], "utf-8")
+                elif field.types[0] == gguf.GGUFValueType.INT32:
+                    metadata[field_name] = int(field.parts[field.data[-1]])
+                elif field.types[0] == gguf.GGUFValueType.F32:
+                    metadata[field_name] = float(field.parts[field.data[-1]])
+                elif field.types[0] == gguf.GGUFValueType.BOOL:
+                    metadata[field_name] = bool(field.parts[field.data[-1]])
+        except:
+            continue
+    return metadata
+
+def gguf_sd_loader(path, handle_prefix="model.diffusion_model.", is_text_model=False):
     """
     Read state dict as fake tensors
     """
@@ -136,9 +155,12 @@ def gguf_sd_loader(path, handle_prefix="model.diffusion_model.", return_arch=Fal
         max_key = max(qsd.keys(), key=lambda k: qsd[k].numel())
         state_dict[max_key].is_largest_weight = True
 
-    if return_arch:
-        return (state_dict, arch_str)
-    return state_dict
+    # extra info to return
+    extra = {
+        "arch_str": arch_str,
+        "metadata": get_gguf_metadata(reader)
+    }
+    return (state_dict, extra)
 
 # for remapping llama.cpp -> original key names
 T5_SD_MAP = {
@@ -246,7 +268,7 @@ def gguf_mmproj_loader(path):
 
     logging.info(f"Using mmproj '{target[0]}' for text encoder '{tenc_fname}'.")
     target = os.path.join(root, target[0])
-    vsd = gguf_sd_loader(target, is_text_model=True)
+    vsd, _ = gguf_sd_loader(target, is_text_model=True)
 
     # concat 4D to 5D
     if "v.patch_embd.weight.1" in vsd:
@@ -375,7 +397,8 @@ def gguf_tekken_tokenizer_loader(path, temb_shape):
     return torch.ByteTensor(list(json.dumps(data).encode('utf-8')))
 
 def gguf_clip_loader(path):
-    sd, arch = gguf_sd_loader(path, return_arch=True, is_text_model=True)
+    sd, extra = gguf_sd_loader(path, is_text_model=True)
+    arch = extra.get("arch_str", None)
     if arch in {"t5", "t5encoder"}:
         temb_key = "token_embd.weight"
         if temb_key in sd and sd[temb_key].shape == (256384, 4096):

nodes.py

@@ -165,9 +165,9 @@ class UnetLoaderGGUF:
 
         # init model
         unet_path = folder_paths.get_full_path("unet", unet_name)
-        sd = gguf_sd_loader(unet_path)
+        sd, extra = gguf_sd_loader(unet_path)
         model = comfy.sd.load_diffusion_model_state_dict(
-            sd, model_options={"custom_operations": ops}
+            sd, model_options={"custom_operations": ops}, metadata=extra.get("metadata", {})
         )
         if model is None:
             logging.error("ERROR UNSUPPORTED UNET {}".format(unet_path))
@@ -319,3 +319,4 @@ NODE_CLASS_MAPPINGS = {
     "QuadrupleCLIPLoaderGGUF": QuadrupleCLIPLoaderGGUF,
     "UnetLoaderGGUFAdvanced": UnetLoaderGGUFAdvanced,
 }
+