Fix mutable default argument and unreachable exception handler

[Mr-Neutr0n]

Summary

• fastchat/serve/gradio_block_arena_anony.py: Replace mutable default argument sampling_boost_models=[] with None in get_sample_weight(). Mutable defaults are shared across all calls and can lead to subtle, hard-to-diagnose bugs when the list is mutated.

• fastchat/llm_judge/common.py: Reorder exception handlers in chat_completion_openai_azure() so that openai.error.InvalidRequestError is caught before its parent class openai.error.OpenAIError. The previous ordering made the InvalidRequestError handler unreachable dead code, meaning invalid request errors were retried instead of breaking immediately.

Test plan

• Verified get_sample_weight() still works correctly with and without sampling_boost_models argument
• Verified exception handler ordering now catches InvalidRequestError before the generic OpenAIError
• No functional changes beyond the bug fixes

[Mr-Neutr0n]

CI failure diagnosed + fixed (3475c71).

The Python package workflow fails on the black --check . step. The mutable-default fix in the previous commit was a single long line:

def get_sample_weight(model, outage_models, sampling_weights, sampling_boost_models=None):

That's 88+ characters, which exceeds black's default 88-char line length. Fixed by wrapping the signature across three lines (no behavior change).

Verified locally:

$ black --check .
All done! ✨ 🍰 🍰
148 files would be left unchanged.

The pylint step also has dependency issues locally on my machine (the CI's pylint 2.x + astroid pin don't play nicely with the modern setuptools/wrapt stack I have installed), but that's a pylint+setuptools+wrapt ecosystem issue unrelated to this PR. If the CI's pinned versions still pass for pylint after this black fix, the run should go green.

[Mr-Neutr0n]

Quick follow-up: the branch now has the formatting fix pushed (3475c71), the current head is mergeable, and the visible build (3.10) check is green. If this still looks acceptable on your side, I would be happy to see it merged.

[Mr-Neutr0n]

Closing this one to tidy up my open pull requests.

It's been open around five months with no review activity, and I'd rather withdraw it than leave it sitting in your queue. Nothing needed from you, and no hard feelings at all.

If the fix is still wanted, this can be reopened, or I'm happy to redo it properly against current main. Apologies for the noise.