[C++][Python] Duplicate csv header when table batches start with empty #36889
Description
Describe the bug, including details regarding any error messages, version, and platform.
pyarrow.csv.write_csv works as expected, but when the first record batch in a table is empty, it writes two headers (on 2 different lines) instead of one:
import pyarrow.csv
import pyarrow as pa
import io
table = pa.table({"col1": ["a", "b", "c"]})
with io.BytesIO() as fp:
pyarrow.csv.write_csv(table, fp)
fp.seek(0)
assert fp.read() == b'"col1"\n"a"\n"b"\n"c"\n'
with io.BytesIO() as fp:
pyarrow.csv.write_csv(pa.concat_tables([table.schema.empty_table(), table]), fp)
fp.seek(0)
# THIS IS WRONG:
assert fp.read() == b'"col1"\n"col1"\n"a"\n"b"\n"c"\n'Component(s)
Python