[Quantization] Deprecate Long Tail of Schemes

[robertgshaw2-redhat]

SUMMARY

• start deprecation process for long tail of quantization schemes
• we will have 1 release with the ability to enable the deprecated stuff, then remove completely

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[gemini-code-assist]

Code Review

This pull request introduces a deprecation mechanism for a number of quantization schemes. A new allow_deprecated_quantization flag is added to ModelConfig and exposed as a command-line argument, allowing users to continue using these schemes with a warning. The implementation is clear and the deprecation logic is sound. I have one suggestion to improve code clarity by removing an unused parameter.

[gemini-code-assist]

The allow_deprecated parameter is introduced in this function's signature but it's not used within the function body. The deprecation logic is correctly handled in vllm.config.model.ModelConfig._verify_quantization. To avoid confusion for future developers who might expect this parameter to have an effect, it should be removed.

def get_quantization_config(quantization: str) -> type[QuantizationConfig]:

[yewentao256]

Thanks for the work! Will allow_deprecated_quantization=True only in test_auto_round.py be enough?

[mergify]

Hi @robertgshaw2-redhat, the pre-commit checks have failed. Please run:

uv pip install pre-commit
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pre-commit run --all-files

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[micah-wil]

Hi, I noticed LM Eval Large Models failed on the nightly CI run after this PR: https://buildkite.com/vllm/ci/builds/46314/steps/canvas?sid=019ba18f-0a1a-4482-82d8-b8c102fd92c0. I've made a PR to allow for deprecated quantization similar to what you've done here for the other relevant tests: #32065.