always set self.config

src/huggingface_hub/hub_mixin.py

@@ -33,6 +33,9 @@ class ModelHubMixin:
     of mixin integration with the Hub. Check out our [integration guide](../guides/integrations) for more instructions.
     """
 
+    config: Optional[Union[dict, "DataclassInstance"]] = None
+    # ^ optional config attribute automatically set in `from_pretrained` (if not already set by the subclass)
+
     def save_pretrained(
         self,
         save_directory: Union[str, Path],
@@ -160,6 +163,7 @@ def from_pretrained(
             except HfHubHTTPError as e:
                 logger.info(f"{CONFIG_NAME} not found on the HuggingFace Hub: {str(e)}")
 
+        config = None
         if config_file is not None:
             # Read config
             with open(config_file, "r", encoding="utf-8") as f:
@@ -184,7 +188,7 @@ def from_pretrained(
                 # Forward config to model initialization
                 model_kwargs["config"] = config
 
-        return cls._from_pretrained(
+        instance = cls._from_pretrained(
             model_id=str(model_id),
             revision=revision,
             cache_dir=cache_dir,
@@ -196,6 +200,13 @@ def from_pretrained(
             **model_kwargs,
         )
 
+        # Implicitly set the config as instance attribute if not already set by the class
+        # This way `config` will be available when calling `save_pretrained` or `push_to_hub`.
+        if config is not None and instance.config is None:
+            instance.config = config
+
+        return instance
+
     @classmethod
     def _from_pretrained(
         cls: Type[T],