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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Python] type checkers broken for pyarrow.compute and other sub-modules since PyArrow 24.0+","articleBody":"### Describe the bug, including details regarding any error messages, version, and platform.\n\nConsider the following snippet:\n\n```shell\ndocker run \\\n  --rm \\\n  -it python:3.13 \\\n  bash\n\npip install 'pyarrow\u003e=24.0' 'mypy'\n\ncat \u003e test.py \u003c\u003cEOF\nimport pyarrow as pa\nimport pyarrow.compute as pa_compute\n\ndef all_ones(arr) -\u003e bool:\n    return pa_compute.all(pa_compute.equal(arr, 1))\n\nif __name__ == \"__main__\":\n    X = pa.array([1, 1, 1])\n    print(f\"all ones?: {all_ones(X)}\")\nEOF\n```\n\nThis is totally plausible `pyarrow` code and works as expected.\n\n```console\n$ python ./test.py\nall ones?: True\n```\n\nBut `mypy` complains about it referencing things that don't exist in `pyarrow`\n\n```console\n$ mypy --version\nmypy 1.20.2 (compiled: yes)\n\n$ mypy ./test.py\ntest.py:5: error: Module has no attribute \"all\"  [attr-defined]\ntest.py:5: error: Module has no attribute \"equal\"  [attr-defined]\nFound 2 errors in 1 file (checked 1 source file)\n```\n\n## Notes\n\nSimilar errors are not surfaced by type checkers like `mypy` on `pyarrow\u003c24`, so I strongly suspect this is related  to something new in the 24.0 release. Possibly the introduction of type-checking infrastructure (a `py.typed` file and `.pyi` stubs), around #48618\n\nMaybe the `.pyi` stub file(s) are incomplete? At https://mypy.readthedocs.io/en/stable/stubs.html#creating-a-stub, I see:\n\n\u003e _If a directory contains both a `.py` and a `.pyi` file for the same module, the `.pyi` file takes precedence._\n\nOr maybe `mypy` does not handle well situations where things are added to `globals` at import time like this?\n\nhttps://github.com/apache/arrow/blob/acd8e442939b5fbf90d0cd65ca506514ec3851c4/python/pyarrow/compute.py#L343\n\nThanks for your time and consideration.\n\n### Component(s)\n\nPython","author":{"url":"https://github.com/jameslamb","@type":"Person","name":"jameslamb"},"datePublished":"2026-04-21T21:27:31.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/49831/arrow/issues/49831"}