Re: [I] StructArray from ArrayData Ignores Offset [arrow-rs]

["westonpace (via GitHub)" <gi...@apache.org>]

westonpace commented on issue #6151:
URL: https://github.com/apache/arrow-rs/issues/6151#issuecomment-2773833480

   Here's a small datafusion-python example showing the potential dangers in an end-to-end environment:
   
   ```
   import pyarrow as pa
   from datafusion import SessionContext
   
   ctx = SessionContext()
   
   batch = pa.table({"s": [{"x": 7}, {"x": 7}, None, {"x": None}, {"x": 7}] }).to_batches()[0]
   sliced = batch.slice(1, 3)
   
   print(ctx.create_dataframe([[sliced]]).show())
   
   hand_sliced = pa.table({"s": [{"x": 7}, None, {"x": None}] }).to_batches()[0]
   
   print(ctx.create_dataframe([[hand_sliced]]).show())
   
   assert sliced == hand_sliced
   ```
   
   Output:
   
   ```
   DataFrame()
   +--------+
   | s      |
   +--------+
   | {x: 7} |
   |        |
   | {x: 0} |
   +--------+
   None
   DataFrame()
   +--------+
   | s      |
   +--------+
   | {x: 7} |
   |        |
   | {x: }  |
   +--------+
   None
   ```
   
   The validity of the inner array is incorrect because the offset is lost and so we silently get `{x: 0}` instead of `{x: null}`.


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org