[BugFix][DataProcessor] Add validate_model_path to fail fast on bad model path or unreachable network

[gongweibao]

Motivation

When model_name_or_path is incorrect or the network is unreachable, DataProcessor.__init__ hangs for 50s+ with zero output because from_pretrained silently retries HuggingFace Hub connections (10s timeout × 5 retries + exponential backoff). Users have no idea what is happening and assume the program is dead.

Modifications

• Extract validate_model_path() into fastdeploy/input/utils.py: a lightweight pre-check that runs before any from_pretrained call. It checks whether the path is a local dir/file; if not, it warns the user and does a quick socket.create_connection probe (3s timeout) to detect network issues immediately.
• Call validate_model_path() in both text_processor.py and v1/text_processor.py: one-line change in each DataProcessor.__init__, replacing the previous duplicated inline logic that had a bug (misidentified HF repo ids containing / as local paths).
• Add unit tests in tests/input/test_validate_model_path.py: 7 test cases covering normal paths (local dir, local file), non-local path with reachable/unreachable network, boundary values (HF org/model name with /, empty string), and socket timeout.

Usage or Command

# Run unit tests
python -m pytest tests/input/test_validate_model_path.py -v

Accuracy Tests

Not applicable — this change only adds a pre-check warning before from_pretrained calls. It does not modify model forward code, kernels, or any inference logic.

Checklist

• Add at least a tag in the PR title. ([BugFix], [DataProcessor])
• Format your code, run pre-commit before commit.
• Add unit tests. (7 cases in tests/input/test_validate_model_path.py)
• Provide accuracy results. (N/A, no model output change)

[paddle-bot]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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