Streaming cross join with empty left input doesn't create a file #23084
Description
df = pl.LazyFrame(data={"col1": ["a"]})
df_empty = pl.LazyFrame(
data={"col1": []},
schema={"col1": str},
)
# test right empty - file created
df.join(df_empty, how="cross").sink_ipc("cross1.ipc", engine="streaming")
# test left empty - no file
df_empty.join(df, how="cross").sink_ipc("cross2.ipc", engine="streaming")
# test both empty - no file
df_empty.join(df_empty, how="cross").sink_ipc("cross3.ipc", engine="streaming")