Florian Jetter created ARROW-8142:
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Summary: [Python/C++] Casting empty table from after parquet
roundtrip causes critical failure
Key: ARROW-8142
URL: https://issues.apache.org/jira/browse/ARROW-8142
Project: Apache Arrow
Issue Type: Bug
Reporter: Florian Jetter
When casting a schema of an empty table from dict encoded to non-dict encoded
type a critical error is raised and not handled causing the interpreter to shut
down.
This only happens after a parquet roundtrip
{code:python}
import pyarrow as paimport pandas as pdimport pyarrow.parquet as pq
df = pd.DataFrame({"col": ["a"]}).astype({"col": "category"}).iloc[:0]
table = pa.Table.from_pandas(df)field = table.schema[0]
new_field = pa.field(field.name, field.type.value_type, field.nullable,
field.metadata)
buf = pa.BufferOutputStream()
pq.write_table(table, buf)
reader = pa.BufferReader(buf.getvalue().to_pybytes())
table = pq.read_table(reader)
schema = table.schema.remove(0).insert(0, new_field)
new_table = table.cast(schema)
assert new_table.schema == schema
{code}
Output
{code:java}
WARNING: Logging before InitGoogleLogging() is written to STDERR
F0318 09:55:14.266649 299722176 table.cc:47] Check failed: (chunks.size()) >
(0) cannot construct ChunkedArray from empty vector and omitted type {code}
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