[Bugfix] Fix Mistral v0.3 Weight Loading

[robertgshaw2-neuralmagic]

FILL IN THE PR DESCRIPTION HERE

Mistral v0.3 has multiple copies of the safetensors file on hf hub

• considated.safetensors << which has all the weights w/ a different state dict
• model.0001-of-0004.safetensors << which has the shard of the weights w/ the llama state dict

This PR adds support for downloading the model.safetensors.index.json file. We then look into this file to determine which files to use, skipping any files that are not found in the index.

Validated this works will mistral-v0.3, llama-3 (which has an index, but no consolidated), tinyllama (which has no index) and with HF_HUB_OFFLINE=1.

This PR still has the issue that it will download all weights as opposed to just the shards. We should see if we can fix this in a follow up PR. We currently rely on allow_patterns="*.safetensors" in snapshot_download today so this will be tricky

Validated with:

• mistral v0.3 (index.json, sharded, consolidated.safetensors
• tinyllama (no index.json)
• llama (index.json, but no consolidated.safetensors)
• HF_HUB_OFFLINE=0
• HF_HUB_OFFLINE=1

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[simon-mo]

Stamp to unblock merge

[ShukantPal]

Does this fix #4989 by any chance?

[robertgshaw2-neuralmagic]

Yep

[jmlb]

Hi, in what vllm version is the KeyError fixed. vllm-0.4.2 still returns the error with Mistral-7B-Instruct-v0.3

[ShukantPal]

@jmlb The fix probably hasn't been published to PyPI yet. You can install vLLM's main branch directly with

pip install git+https://github.com/vllm-project/vllm.git@main