fix(langchain): correctly initialize huggingface models in init_chat_model

[aaron-seq]

Description:

This change fixes a ValidationError that occurred when using init_chat_model with model_provider="huggingface".

The previous implementation incorrectly passed all keyword arguments directly to the ChatHuggingFace constructor, which expects an llm object rather than a model_id. This caused a Pydantic error when arguments like task were provided.

The fix updates the logic to first correctly instantiate a HuggingFacePipeline object using the from_model_id class method, which properly handles arguments like task. This initialized pipeline object is then passed to the ChatHuggingFace wrapper, resolving the issue.

A unit test has been added to verify the fix and prevent regressions.

Issue:

Fixes #28226

Dependencies:

None

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Project	Deployment	Preview	Comments	Updated (UTC)
langchain	Ready	Preview	Comment	Sep 25, 2025 0:45am