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BUG: .to_parquet fails with schema for string[pyarrow] but not string[python] #61316

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noahblakesmith opened this issue Apr 20, 2025 · 1 comment
Open
3 tasks done
Labels
Arrow pyarrow functionality Bug Closing Candidate May be closeable, needs more eyeballs Upstream issue Issue related to pandas dependency

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@noahblakesmith
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Pandas version checks

  • I have checked that this issue has not already been reported.

  • I have confirmed this bug exists on the latest version of pandas.

  • I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import random
import string

import pandas as pd
import pyarrow as pa

# Gen ~1m bytes of text
txt = "".join(random.choices(string.printable, k=int(1e6)))

# Gen dataframes
data = {"c": [txt] * int(5e3)}
df_v0 = pd.DataFrame(data, dtype="string[python]")
df_v1 = pd.DataFrame(data, dtype="string[pyarrow]")

# Write to parquets using schema
schema = pa.schema([pa.field("c", pa.string())])
df_v0.to_parquet(path="df_v0.parquet", schema=schema)
df_v1.to_parquet(path="df_v1.parquet", schema=schema)

Issue Description

Writing to a parquet file fails when dtype is string[pyarrow] but not for string[python].

Expected Behavior

I believe df_v1 should write to a parquet file like df_v0 does.

Installed Versions

INSTALLED VERSIONS

commit : 0691c5c
python : 3.10.16
python-bits : 64
OS : Linux
OS-release : 6.11.0-1012-azure
Version : #12~24.04.1-Ubuntu SMP Mon Mar 10 19:00:39 UTC 2025
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : None
LANG : C.UTF-8
LOCALE : en_US.UTF-8

pandas : 2.2.3
numpy : 2.2.2
pytz : 2025.2
dateutil : 2.9.0.post0
pip : 25.0
Cython : None
sphinx : None
IPython : 8.35.0
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : 4.13.4
blosc : None
bottleneck : None
dataframe-api-compat : None
fastparquet : None
fsspec : 2025.3.2
html5lib : None
hypothesis : None
gcsfs : None
jinja2 : 3.1.6
lxml.etree : 5.3.1
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : 3.1.5
pandas_gbq : None
psycopg2 : None
pymysql : None
pyarrow : 19.0.1
pyreadstat : None
pytest : None
python-calamine : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : 2.0.39
tables : None
tabulate : None
xarray : None
xlrd : 2.0.1
xlsxwriter : None
zstandard : None
tzdata : 2025.2
qtpy : None
pyqt5 : None

@noahblakesmith noahblakesmith added Bug Needs Triage Issue that has not been reviewed by a pandas team member labels Apr 20, 2025
@rhshadrach
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Thanks for the report. It seems to me this might be a pyarrow issue.

txt = "".join(random.choices(string.printable, k=int(1e6)))

# Gen dataframes
data = {"c": [txt] * int(5e3)}
df_v0 = pd.DataFrame(data, dtype="string[python]")
df_v1 = pd.DataFrame(data, dtype="string[pyarrow]")

type_ = pa.string()
pa.array(df_v0["c"], type=type_, from_pandas=True, safe=True)  # Success
pa.array(df_v1["c"], type=type_, from_pandas=True, safe=True)  # Fails

@rhshadrach rhshadrach added Closing Candidate May be closeable, needs more eyeballs Upstream issue Issue related to pandas dependency Arrow pyarrow functionality and removed Needs Triage Issue that has not been reviewed by a pandas team member labels Apr 22, 2025
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Labels
Arrow pyarrow functionality Bug Closing Candidate May be closeable, needs more eyeballs Upstream issue Issue related to pandas dependency
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