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BUG: read_csv with pyarrow engine cannot handle single-line CSV files

Arrowpyarrow functionalitypyarrow functionality

Bug

IO CSVread_csv, to_csvread_csv, to_csv

Status: Open.

#62635 In pandas-dev/pandas;

· jorisvandenbossche opened on Oct 9, 2025

BUG: Drop duplicates bug when using pyarrow (version 21.0.0) backend

Arrowpyarrow functionalitypyarrow functionality

Bug

duplicatedduplicated, drop_duplicatesduplicated, drop_duplicates

Status: Open.

#62611 In pandas-dev/pandas;

· flori-ko opened on Oct 7, 2025

BUG: ArrowEA._cast_pointwise_result([Decimal(NaN)])

Arrowpyarrow functionalitypyarrow functionality

Bug

Status: Open.

#62522 In pandas-dev/pandas;

· jbrockmendel opened on Sep 30, 2025

BUG: <code>np.isnan</code> raises on pyarrow dtypes

Arrowpyarrow functionalitypyarrow functionality

Bug

PDEP missing valuesIssues that would be addressed by the Ice Cream Agreement from the Aug 2023 sprintIssues that would be addressed by the Ice Cream Agreement from the Aug 2023 sprint

Status: Open.

#62506 In pandas-dev/pandas;

· MarcoGorelli opened on Sep 29, 2025

BUG: _get_common_dtype with date32[pyarrow] and null[pyarrow]

Arrowpyarrow functionalitypyarrow functionality

Bug

datetime.datestdlib datetime.date supportstdlib datetime.date support

Dtype ConversionsUnexpected or buggy dtype conversionsUnexpected or buggy dtype conversions

ReshapingConcat, Merge/Join, Stack/Unstack, ExplodeConcat, Merge/Join, Stack/Unstack, Explode

Status: Open.

#62343 In pandas-dev/pandas;

· jbrockmendel opened on Sep 15, 2025

BUG: ArrowEA.astype to categorical returning all-NaT

Arrowpyarrow functionalitypyarrow functionality

Bug

CategoricalCategorical Data TypeCategorical Data Type

datetime.datestdlib datetime.date supportstdlib datetime.date support

Dtype ConversionsUnexpected or buggy dtype conversionsUnexpected or buggy dtype conversions

Status: Open.

#62051 In pandas-dev/pandas;

· jbrockmendel opened on Aug 5, 2025

BUG: Dataframe.aggregate drops pyarrow backend for lambda aggregation functions

ApplyApply, Aggregate, Transform, MapApply, Aggregate, Transform, Map

Arrowpyarrow functionalitypyarrow functionality

Bug

pyarrow dtype retentionop with pyarrow dtype -> expect pyarrow resultop with pyarrow dtype -> expect pyarrow result

Status: Open.

#61812 In pandas-dev/pandas;

· flori-ko opened on Jul 8, 2025

BUG: Errors using pyarrow datetime types on windows

Arrowpyarrow functionalitypyarrow functionality

Bug

DatetimeDatetime data dtypeDatetime data dtype

Docs

Upstream issueIssue related to pandas dependencyIssue related to pandas dependency

WindowsWindows OSWindows OS

Status: Open.

#61782 In pandas-dev/pandas;

· Liam3851 opened on Jul 5, 2025

PERF: Arrow dtypes are much slower than Numpy for DataFrame.apply

ApplyApply, Aggregate, Transform, MapApply, Aggregate, Transform, Map

Arrowpyarrow functionalitypyarrow functionality

PerformanceMemory or execution speed performanceMemory or execution speed performance

Status: Open.

#61747 In pandas-dev/pandas;

· ehsantn opened on Jun 30, 2025

BUG: <code>to_numeric</code> fails to convert a Pyarrow Decimal series containing NA values.

Arrowpyarrow functionalitypyarrow functionality

Bug

Dtype ConversionsUnexpected or buggy dtype conversionsUnexpected or buggy dtype conversions

Status: Open.

#61641 In pandas-dev/pandas;

· kzvezdarov opened on Jun 12, 2025

Moving to PyArrow dtypes by default

Arrowpyarrow functionalitypyarrow functionality

Needs DiscussionRequires discussion from core team before further actionRequires discussion from core team before further action

Status: Open.

#61618 In pandas-dev/pandas;

· datapythonista opened on Jun 9, 2025

BUG: Passing string[pyarrow] to the dtype parameter of e.g. csv_read() does produce a string type Series

Arrowpyarrow functionalitypyarrow functionality

Dtype ConversionsUnexpected or buggy dtype conversionsUnexpected or buggy dtype conversions

IO CSVread_csv, to_csvread_csv, to_csv

Needs DiscussionRequires discussion from core team before further actionRequires discussion from core team before further action

StringsString extension data type and string dataString extension data type and string data

Status: Open.

#61496 In pandas-dev/pandas;

· ClauPet opened on May 26, 2025