Fix typing for `safetensors_load_strategy` (#24641)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/config/load.py

@@ -51,7 +51,7 @@ class LoadConfig:
     download_dir: Optional[str] = None
     """Directory to download and load the weights, default to the default
     cache directory of Hugging Face."""
-    safetensors_load_strategy: Optional[str] = "lazy"
+    safetensors_load_strategy: str = "lazy"
     """Specifies the loading strategy for safetensors weights.
     - "lazy" (default): Weights are memory-mapped from the file. This enables
       on-demand loading and is highly efficient for models on local storage.

vllm/engine/arg_utils.py

@@ -289,8 +289,7 @@ class EngineArgs:
     trust_remote_code: bool = ModelConfig.trust_remote_code
     allowed_local_media_path: str = ModelConfig.allowed_local_media_path
     download_dir: Optional[str] = LoadConfig.download_dir
-    safetensors_load_strategy: Optional[
-        str] = LoadConfig.safetensors_load_strategy
+    safetensors_load_strategy: str = LoadConfig.safetensors_load_strategy
     load_format: Union[str, LoadFormats] = LoadConfig.load_format
     config_format: str = ModelConfig.config_format
     dtype: ModelDType = ModelConfig.dtype

vllm/model_executor/model_loader/weight_utils.py

@@ -519,7 +519,7 @@ def np_cache_weights_iterator(
 def safetensors_weights_iterator(
     hf_weights_files: list[str],
     use_tqdm_on_load: bool,
-    safetensors_load_strategy: Optional[str] = "lazy",
+    safetensors_load_strategy: str = "lazy",
 ) -> Generator[tuple[str, torch.Tensor], None, None]:
     """Iterate over the weights in the model safetensor files."""
     loading_desc = "Loading safetensors checkpoint shards"