panic when stream top N has a large limit

[xxchan]

Describe the bug

No response

To Reproduce

dev=> create table t(x int);
CREATE_TABLE
dev=> create materialized view mv as select generate_series(1,x,1) y from t;
CREATE_MATERIALIZED_VIEW
dev=> create materialized view mv2 as select * from mv order by y limit 5000;
CREATE_MATERIALIZED_VIEW
dev=> insert into t values (20000);
INSERT 0 1

thread 'risingwave-streaming-actor' panicked at 'assertion failed: `(left == right)`
  left: `904`,
 right: `5000`', src/common/src/array/stream_chunk.rs:90:13

Expected behavior

No response

Additional context

No response

[xxchan]

ProjectSet produced a large chunk, and TopN failed to handle large chunk & limit correctly, since here's an unused Option:

risingwave/src/stream/src/executor/top_n_executor.rs

Line 129 in d82a95e

data_chunk_builder.append_one_row_from_datums(row.0.iter())?;

[xxchan]

Look forward to rust-lang/rust#71368 🤪

[BugenZhao]

We may mark the methods #[must_use] manually for now.

[xxchan]

We may mark the methods #[must_use] manually for now.

It's Result<Option<>>. You can't mark it 😄