[wenjinhust]

Overview

Fix CI failures where ColPali model loading crashes with AttributeError: 'dict' object has no attribute 'hidden_size' because recent Transformers versions expose text_config as a plain dict. Handle both the dict and config-object forms when extracting the text hidden size.

Related: #60823 (ported ColPali configs/processors to upstream Transformers, which surfaced this issue).

Claims

• Fixes AttributeError: 'dict' object has no attribute 'hidden_size' in ColPaliModel.__init__ when loading vidore/colpali-v1.3-hf with recent Transformers versions, restoring model initialization.
• Restores the ColPali CI coverage that regressed: model initialization tests and late-interaction pooling entrypoint tests on NVIDIA and AMD MI355.
• Preserves backward compatibility with the config-object form of text_config used by older Transformers versions.

Validation

Before this fix, CI build 96076 failed with the same traceback across the following jobs:

• nvidia-h200-mig-35gb-basic-models-extra-initialization-shard-4
  • tests/models/test_initialization.py::test_can_initialize_large_subset[ColPaliForRetrieval]
• nvidia-h200-mig-35gb-entrypoints-integration-pooling-shard-3-slash-3
  • tests/entrypoints/pooling/scoring/test_late_interaction_offline_vision.py::test_query_text_vs_docs_image
• amd-mi355-dpx-entrypoints-integration-pooling-shard-1-slash-2 / -shard-2-slash-2
  • test_query_image_vs_docs_text, test_query_text_vs_docs_image, test_query_text_vs_docs_mix

Failure (vllm/model_executor/models/colpali.py:123, before fix):

AttributeError: 'dict' object has no attribute 'hidden_size'
    hidden_size = config.text_config.hidden_size

Steps to reproduce / validate:

pytest tests/models/test_initialization.py -k ColPaliForRetrieval
pytest tests/entrypoints/pooling/scoring/test_late_interaction_offline_vision.py

The affected jobs above are re-run in CI to confirm the fix.

Details

Root cause. ColPaliModel.__init__ reads the text hidden size from the top-level config and falls back to config.text_config.hidden_size when hidden_size is absent. After #60823 switched ColPali to the upstream Transformers ColPaliConfig, recent Transformers versions can leave text_config as a plain dict (e.g. when loading vidore/colpali-v1.3-hf), so the attribute access raises AttributeError and model loading aborts during LLM initialization.

Fix. In vllm/model_executor/models/colpali.py, read text_config["hidden_size"] when text_config is a dict, otherwise fall back to getattr(text_config, "hidden_size", None). The existing ValueError fallback is kept for the case where neither form yields a hidden size.

Tradeoffs / limitations. Minimal one-place change with no behavioral impact on the config-object path. No new tests are added; the regression is covered by the existing initialization and late-interaction entrypoint tests listed above.

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[claude]

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[wenjinhust]

/pr-checklist

[ZJY0516]

/ci run

[github-actions]

✅ @wenjinhust, CI is now available for this PR.

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[github-actions]

✅ Triggered Buildkite CI #96090 for commit 5a12ceb5e0ef.

[hmellor]

While this fix works, it is not correct and will only work for existing ColPali checkpoints which define the top level text_config in config.json.

For all supported versions of Transformers the correct location of hidden_size is config.vlm_config.text_config.hidden_size. The Transformers upgrade simply removed the BC that duplicated the text config to the top level. This PR only works because the test checkpoint is old and still contains text_config at the top level of config.json, this will not be the case for new checkpoints.

Correct fix is in #62714