BUG: Validate path type in read_parquet, reject non-path/file-like #62979
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YukunR changed the title 
pandas/tests/io/test_parquet.py Outdated
| def test_read_parquet_valid_path_types(tmp_path, engine): | ||
| # GH #62922 | ||
| df = pd.DataFrame({"a": [1]}) | ||
| path = tmp_path / "test_read_parquet.parquet" | ||
| df.to_parquet(path, engine=engine) | ||
| # str | ||
| read_parquet(str(path), engine=engine) | ||
| # os.PathLike | ||
| read_parquet(pathlib.Path(path), engine=engine) | ||
| # file-like object | ||
| buf = BytesIO() | ||
| df.to_parquet(buf, engine=engine) | ||
| buf.seek(0) | ||
| read_parquet(buf, engine=engine) |
pandas/tests/io/test_parquet.py Outdated
| bad_path_types = [ | ||
| [str(path)], # list | ||
| (str(path),), # tuple | ||
| b"raw-bytes", # bytes | ||
| ] |
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Testing the list case is sufficient
| raise TypeError( | ||
| f"read_parquet expected str/os.PathLike or file-like object, " | ||
| f"got {type(path).__name__} type" | ||
| ) |
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This should probably be done using get_handle in the _get_path_or_handle function.
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Hi, thanks for the review!
I looked into _get_path_or_handle more closely.
get_handle is only invoked when we already know path_or_handle is a string and not a directory. For invalid inputs like a list, we never reach that branch as they get passed through stringify_path unchanged.
Also, _get_path_or_handle is only used in PyArrowImpl.read, not in FastParquetImpl.read. So if we only rely on _get_path_or_handle to validate input, validation coverage would be asymmetric across engines.
So, I propose to validate the path type in read_parquet before engine dispatch. Alternatively, I can factor a small _validate_parquet_path_arg(path) helper and call it at the top of both PyArrowImpl.read and FastParquetImpl.read
Let me know which placement you prefer.
YukunR force-pushed the bug/read_parquet branch from 26b56d6 to 9ff9109 Compare 
| This pull request is stale because it has been open for thirty days with no activity. Please update and respond to this comment if you're still interested in working on this. |
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Description
read_parquetdocumentation specifies that onlystr/os.PathLikeorfile-likeobjects are supported.Previously, passing unexpected container types such as list would reach backends and fail inconsistently.
This PR adds an early
TypeErrorcheck at the public API boundary to provide clear, consistent behaviour across pyarrow / fastparquet engines.Tests are added for both valid and invalid path types.