Set hf_access_token to None when not provided

Author: aireenmei

src/maxtext/configs/pyconfig.py

@@ -135,7 +135,10 @@ def _prepare_for_pydantic(raw_keys: dict[str, Any]) -> dict[str, Any]:
         new_value = [new_value]
 
     # An empty value provided in the configuration is treated as None
-    if key in ("hf_train_files", "hf_eval_files") and new_value == "":
+    if (
+        key in ("hf_train_files", "hf_eval_files", "hf_access_token", "hf_name", "hf_data_dir", "hf_eval_split")
+        and new_value == ""
+    ):
       new_value = None
 
     if key == "run_name" and new_value is None:

src/maxtext/configs/types.py

@@ -994,11 +994,11 @@ class HfDataset(BaseModel):
   """Configuration specific to HuggingFace datasets."""
 
   hf_path: str = Field("", description="Path of the Hugging Face dataset.")
-  hf_name: str = Field("", description="Name of the Hugging Face dataset.")
-  hf_data_dir: PathStr = Field("", description="Data directory for the HF dataset.")
-  hf_train_files: Optional[str] = Field(None, description="Files for the HF training split.")
-  hf_eval_split: str = Field("", description="Name of the HF evaluation split.")
-  hf_eval_files: Optional[str] = Field(None, description="Files for the HF evaluation split.")
+  hf_name: None | str = Field(None, description="Name of the Hugging Face dataset.")
+  hf_data_dir: None | PathStr = Field(None, description="Data directory for the HF dataset.")
+  hf_train_files: None | str = Field(None, description="Files for the HF training split.")
+  hf_eval_split: None | str = Field(None, description="Name of the HF evaluation split.")
+  hf_eval_files: None | str = Field(None, description="Files for the HF evaluation split.")
   hf_access_token: None | str = Field(None, description="Hugging Face API access token.")