bug(python): table.merge_insert does not accept a list of columns

[lukebuehler]

LanceDB version

0.6.13

What happened?

When using merge_insert with multiple columns, then there is an error:

table.merge_insert(["a", "b"])
  .when_matched_update_all()
  .when_not_matched_insert_all()
  .execute(insert_items)

Error:

File "/home/user/.cache/pypoetry/virtualenvs/p-MOM2VVIT-py3.10/lib/python3.10/site-packages/lancedb/table.py", line 485, in merge_insert
    on = [on] if isinstance(on, str) else list(on.iter())
AttributeError: 'list' object has no attribute 'iter'

I think thatt line should be ... else list(iter(on))

This issue exists both in the sync and async table.

Are there known steps to reproduce?

No response

[lukebuehler]

For now, a workaround is:

merge_builder = LanceMergeInsertBuilder(table, on=["a", "b"])
            (merge_builder
                .when_matched_update_all()
                .when_not_matched_insert_all()
                .execute(insert_items))