{"record":{"id":"9e58acca0952cf28","repo":"pola-rs/polars","slug":"the-argument-param-name-r-for-func-name-r-was-deprecated-and-9e58ac","errorCode":null,"errorMessage":"the argument {param.name!r} for {func_name!r}{was_deprecated_and} has been removed in version {param.removed_in}. {param.hint}","messagePattern":"the argument (.+?) for (.+?)(.+?) has been removed in version (.+?)\\. (.+?)","errorType":"exception","errorClass":"ArgumentRemovedError","httpStatus":null,"severity":"error","filePath":"py-polars/src/polars/_utils/expired.py","lineNumber":158,"sourceCode":"                f\" {param.name!r}{was_deprecated_and} has been renamed to\"\n                f\" {param.new_name!r} in version {param.removed_in}.\"\n            )\n            raise ArgumentRemovedError(msg)\n        else:\n            msg = (\n                f\"the argument {param.name!r} for {func_name!r}{was_deprecated_and}\"\n                f\" has been removed in version {param.removed_in}.\"\n                f\" It was renamed to {param.new_name!r}.\"\n            )\n            msg = msg if param.hint is None else f\"{msg} {param.hint}\"\n            raise ArgumentRemovedError(msg)\n    elif isinstance(param, RemovedParameter):\n        msg = (\n            f\"the argument {param.name!r} for {func_name!r}{was_deprecated_and}\"\n            f\" has been removed in version {param.removed_in}.\"\n        )\n        msg = msg if param.hint is None else f\"{msg} {param.hint}\"\n        raise ArgumentRemovedError(msg)\n    else:\n        msg = f\"Unexpected parameter type: {type(param)!r}\"\n        raise TypeError(msg)\n","sourceCodeStart":140,"sourceCodeEnd":162,"githubUrl":"https://github.com/pola-rs/polars/blob/fe841f959ef4d2ceefc05a310d33ed7b1ab24e5e/py-polars/src/polars/_utils/expired.py#L140-L162","documentation":"For a RemovedParameter (an argument deleted outright, not renamed), `wrapper` calls `_raise_removed_argument_error`, raising ArgumentRemovedError stating the argument was removed in the given version, with an optional migration hint appended.","triggerScenarios":"Calling a decorated Polars function with a keyword that was fully removed, e.g. passing `low_memory=True` to a reader that no longer supports it.","commonSituations":"Upgrading Polars past an API-cleanup release; old example code; config files whose keys are splatted into function kwargs.","solutions":["Remove the obsolete keyword argument from the call","Follow the error hint to any replacement behavior","Filter legacy kwargs before splatting config dictionaries into API calls"],"exampleFix":"// before\npl.read_csv(f, low_memory=True)\n// after\npl.read_csv(f)","handlingStrategy":"try-catch","validationCode":"REMOVED = {\"low_memory\"}  # args removed without replacement\nbad = REMOVED & kwargs.keys()\nif bad:\n    kwargs = {k: v for k, v in kwargs.items() if k not in REMOVED}","typeGuard":null,"tryCatchPattern":"try:\n    result = func(**cfg_kwargs)\nexcept ArgumentRemovedError as e:\n    logger.warning(\"dropping removed argument: %s\", e)\n    result = func(**{k: v for k, v in cfg_kwargs.items() if k != removed_name})","preventionTips":["Don't splat raw config dicts into polars API calls; map keys explicitly","Fix all deprecation warnings before the removal release","Pin and regularly upgrade polars so removals happen incrementally"],"tags":["python","polars","removed-argument","api-migration"],"backgroundTag":"deprecated-api-usage","analyzedSha":"fe841f959ef4d2ceefc05a310d33ed7b1ab24e5e","analyzedAt":"2026-09-18T22:14:11.667Z","contentChangedAt":"2026-09-18T22:14:11.667Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}