fix: no panic on empty partition in register_record_batches#1627
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fangchenli wants to merge 1 commit into
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fix: no panic on empty partition in register_record_batches#1627fangchenli wants to merge 1 commit into
fangchenli wants to merge 1 commit into
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`register_record_batches` read the schema via unchecked `partitions.0[0][0]`, which panics when a partition contains no record batches (e.g. the batches of an empty pyarrow table, whose `to_batches()` returns `[]`). Take the schema from the first available batch across all partitions and return a clear error when there is none, mirroring the empty-table handling added for `from_arrow_table` in apache#613. A non-empty later partition now also works instead of panicking on an empty leading one. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
kosiew
approved these changes
Jul 13, 2026
| let schema = partitions.0[0][0].schema(); | ||
| // Take the schema from the first available batch; error instead of | ||
| // panicking when the partitions hold no batches. | ||
| let schema = partitions |
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Could we use partitions.0.iter().find_map(|partition| partition.first()) here instead of iter().flatten().next()? The behavior is the same, but I think it makes the intent a little clearer: find the first record batch in any partition, then use its schema.
| def test_register_record_batches_empty(ctx): | ||
| # A partition list with no record batches carries no schema, so this used to | ||
| # panic on unchecked `[0][0]` indexing. It should now raise a clear error. | ||
| with pytest.raises(ValueError, match="no record batches"): |
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Could we also assert that ctx.register_record_batches("t", []) raises the same clear ValueError? The fix now covers both an empty partition ([[]]) and an empty outer partition list ([]), while the regression test currently locks in only the first case.
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Which issue does this PR close?
Closes #1626 .
Rationale for this change
register_record_batchesread the schema via uncheckedpartitions.0[0][0], which panics when a partition contains no record batches (e.g. the batches of an empty pyarrow table, whoseto_batches()returns[]).What changes are included in this PR?
Take the schema from the first available batch across all partitions and return a clear error when there is none, mirroring the empty-table handling added for
from_arrow_tablein #613. A non-empty later partition now also works instead of panicking on an empty leading one.Are there any user-facing changes?
register_record_batches now raises a catchable Python Exception on empty input instead of aborting with a Rust panic