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BUG: StringArray __array_ufunc__ validation of result should not require strings

Bug

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

Status: Open.

#40800 In pandas-dev/pandas;

· johnflavin opened on Apr 6, 2021

REGR: Index.astype(<numpy string dtype>) started failing

Astype

BytesDtype

IndexRelated to the Index class or subclassesRelated to the Index class or subclasses

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

Status: Open.

#50127 In pandas-dev/pandas;

· jorisvandenbossche opened on Dec 8, 2022

API: with CoW, should every new Series/DataFrame object also have its own new Index objects?

API Design

Copy / view semantics

IndexRelated to the Index class or subclassesRelated to the Index class or subclasses

Status: Open.

#53721 In pandas-dev/pandas;

· jorisvandenbossche opened on Jun 19, 2023

BUG: df1.merge(df2, on='ds', how='outer') not convert column ds to the highest resolution datetime type of the two dfs

Bug

Non-Nanodatetime64/timedelta64 with non-nanosecond resolutiondatetime64/timedelta64 with non-nanosecond resolution

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

Status: Open.

#55212 In pandas-dev/pandas;

· seanslma opened on Sep 20, 2023

PERF: DataFrame.copy(deep=True) returns a view on the original pyarrow buffer

Copy / view semantics

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

PerformanceMemory or execution speed performanceMemory or execution speed performance

Status: Open.

#61930 In pandas-dev/pandas;

· TomAugspurger opened on Jul 23, 2025

API: reconsider returning read-only arrays from DataFrame/Series .array/.values/__array__

API Design

Copy / view semantics

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

Status: Open.

#63099 In pandas-dev/pandas;

· jorisvandenbossche opened on Nov 12, 2025

BUG: .dt.seconds Discrepancy Between NumPy and PyArrow Timedelta Dtypes

Arrowpyarrow functionalitypyarrow functionality

Bug

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

TimedeltaTimedelta data typeTimedelta data type

Status: Open.

#63283 In pandas-dev/pandas;

· mattharrison opened on Dec 6, 2025

BUG(pandas 3.0 regression): drop(index=...) doesn't accept NA values when using arrow dtype in index

Arrowpyarrow functionalitypyarrow functionality

Bug

Missing-datanp.nan, pd.NaT, pd.NA, dropna, isnull, interpolatenp.nan, pd.NaT, pd.NA, dropna, isnull, interpolate

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

Status: Open.

#63304 In pandas-dev/pandas;

· tswast opened on Dec 8, 2025

BUG: (pandas 3.0rc0) str.cat is not retaining index dtype

Bug

IndexRelated to the Index class or subclassesRelated to the Index class or subclasses

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.

#63371 In pandas-dev/pandas;

· galipremsagar opened on Dec 15, 2025

REGR: registered accessors are no longer cached per DataFrame

Accessorsaccessor registration mechanism (not .str, .dt, .cat)accessor registration mechanism (not .str, .dt, .cat)

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

Status: Open.

#63393 In pandas-dev/pandas;

· jorisvandenbossche opened on Dec 17, 2025

BUG: 3.0rc0: comparing StringArrays with == yields a bool[pyarrow] array with no .sum() method

API - ConsistencyInternal Consistency of API/BehaviorInternal Consistency of API/Behavior

Arrowpyarrow functionalitypyarrow functionality

Bug

Status: Open.

#63458 In pandas-dev/pandas;

· flying-sheep opened on Dec 22, 2025

String dtype: differences in regex operations because of engine (Python vs RE2)

API - ConsistencyInternal Consistency of API/BehaviorInternal Consistency of API/Behavior

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

Status: Open.

#63683 In pandas-dev/pandas;

· jorisvandenbossche opened on Jan 14, 2026

BUG: bug in pandas 3.0 with posixpath inside Series

Arrowpyarrow functionalitypyarrow functionality

Bug

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

Status: Open.

#63832 In pandas-dev/pandas;

· vadimpy opened on Jan 23, 2026

RLS: 3.0.x releases

Release

Status: Open.

#63833 In pandas-dev/pandas;

· mroeschke opened on Jan 23, 2026

BUG: DataFrame[StringDtype].where(DataFrame[bool], list[str]) returns object type instead of StringDtype.

Bug

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

Status: Open.

#63842 In pandas-dev/pandas;

· mroeschke opened on Jan 24, 2026

BUG: string regex operation with unicode escape sequence failing

Arrowpyarrow functionalitypyarrow functionality

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

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

Status: Open.

#63901 In pandas-dev/pandas;

· jorisvandenbossche opened on Jan 27, 2026

API/BUG: support for operations with custom objects / object dtype

Numeric OperationsArithmetic, Comparison, and Logical operationsArithmetic, Comparison, and Logical operations

Status: Open.

#64107 In pandas-dev/pandas;

· jorisvandenbossche opened on Feb 10, 2026

BUG: str.replace inconsistency between pyarrow and python types

Arrowpyarrow functionalitypyarrow functionality

Bug

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

Status: Open.

#64872 In pandas-dev/pandas;

· galipremsagar opened on Mar 26, 2026

BUG: Regression when using .str[...] accessor on ArrowExtensionArray

Arrowpyarrow functionalitypyarrow functionality

Bug

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

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

Status: Open.

#65112 In pandas-dev/pandas;

· tehunter opened on Apr 7, 2026

BUG: Regression - df[key] = df[key] / x silently drops assignment on MultiIndex columns with mixed-dtype level and single sub-column

IndexingRelated to indexing on series/frames, not to indexes themselvesRelated to indexing on series/frames, not to indexes themselves

MultiIndex

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

Status: Open.

#65118 In pandas-dev/pandas;

· aukeschaap opened on Apr 8, 2026

BUG: interpolate(method="linear", limit_direction="forward") leaves NAs unchanged for pyarrow dtype

Arrowpyarrow functionalitypyarrow functionality

Bug

Missing-datanp.nan, pd.NaT, pd.NA, dropna, isnull, interpolatenp.nan, pd.NaT, pd.NA, dropna, isnull, interpolate

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

Status: Open.

#65345 In pandas-dev/pandas;

· jdamp opened on Apr 23, 2026

BUG: Preserve StringDtype in where with list-like other

Bug

ConditionalsE.g. where, mask, case_whenE.g. where, mask, case_when

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

Status: Open (in progress).

pandas-dev/pandasnumber 64040

#64040 In pandas-dev/pandas;

· sanrishi opened on Feb 5, 2026

BUG: add _str_getitem to ArrowStringArrayMixin

Arrowpyarrow functionalitypyarrow functionality

Bug

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

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

Status: Open (in progress).

pandas-dev/pandasnumber 65113

#65113 In pandas-dev/pandas;

· tehunter opened on Apr 7, 2026

BUG: Timedeltas less than 1 second truncate to 0

Numeric OperationsArithmetic, Comparison, and Logical operationsArithmetic, Comparison, and Logical operations

RegressionFunctionality that used to work in a prior pandas versionFunctionality that used to work in a prior pandas version

TimedeltaTimedelta data typeTimedelta data type

Status: Open.

#65608 In pandas-dev/pandas;

· cdholmes opened on May 12, 2026

BUG: Data corruption after .eval(..., inplace=True).

Bug

Copy / view semantics

expressionspd.eval, query, pd.colpd.eval, query, pd.col

Status: Open.

#65664 In pandas-dev/pandas;

· VukanJ opened on May 16, 2026