Repository: vllm-project/vllm
Pull request: [Bugfix] handle hf_config with architectures == None
`hf_config` is of type `PretrainedConfig` which has the field `architectures` that is an optional list. When not specified the attribute is given the value `None` ([REF](https://github.com/huggingface/transformers/blob/09f9f566de83eef1f13ee83b5a1bbeebde5c80c1/src/transformers/configuration_utils.py#L293)). So `getattr()` returns None which then causes a `TypeError: argument of type 'NoneType' is not iterable` error due to the `in` statement. This PR adds a check to avoid that TypeError.

FIX https://github.com/vllm-project/vllm/issues/583
(this issue was resolved by adding the `architectures` field manually, but a config.json is valid without it)

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Problem statement:
'NoneType' object is not iterable error when I try to load the llama-2-7b-chat model.
I downloaded the llama-2-7b-chat model straight from meta and I'm trying to load it through vLLM, after taking 5-10 mins loading the tokenizer, it gives me the following error:

-> for arch in architectures: 
'NoneType' object is not iterable

Any way to resolve this issue?

Hints from issue discussion:
Fixed: added an architecture entry in the config.json file as it was missing
"architectures": ["LlamaForCausalLM"]

Commit message: [Bugfix] handle hf_config with architectures == None

Signed-off-by: Travis Johnson <tsjohnso@us.ibm.com>

Patch to review:
diff --git a/vllm/config.py b/vllm/config.py
index 753fc33e9b71..89d6b2dd9bd7 100644
--- a/vllm/config.py
+++ b/vllm/config.py
@@ -158,7 +158,8 @@ def _verify_load_format(self) -> None:
 
         # TODO: Remove this check once HF updates the pt weights of Mixtral.
         architectures = getattr(self.hf_config, "architectures", [])
-        if "MixtralForCausalLM" in architectures and load_format == "pt":
+        if architectures and "MixtralForCausalLM" in architectures \
+            and load_format == "pt":
             raise ValueError(
                 "Currently, the 'pt' format is not supported for Mixtral. "
                 "Please use the 'safetensors' format instead. ")


Code review comments:
diff_hunk: @@ -158,7 +158,8 @@ def _verify_load_format(self) -> None:
 
         # TODO: Remove this check once HF updates the pt weights of Mixtral.
         architectures = getattr(self.hf_config, "architectures", [])
-        if "MixtralForCausalLM" in architectures and load_format == "pt":
+        if architectures and "MixtralForCausalLM" in architectures \
path: vllm/config.py
text: @user1:
```suggestion
        # architectures can be None instead of []
        if architectures and "MixtralForCausalLM" in architectures \
```