felipecrv commented on PR #37877:
URL: https://github.com/apache/arrow/pull/37877#issuecomment-1743626515

   > I would therefore prefer we stick with the behaviour of ListArray where 
nulls must mask a valid slice.
   
   @tustvold note that the `List<T>` spec allows null list entries to be 
non-empty. Additionally, it would not be possible to leave `offsets[i]` 
unspecified since the length of potentially non-null entry `i - 1` depends on 
`offsets[i]` being defined as the limit of that slice.
   
   > Similar to the layout of variable-size binary, a null value may correspond 
to a non-empty segment in the child array. When this is true, the content of 
the corresponding segment can be arbitrary.
   
   https://arrow.apache.org/docs/format/Columnar.html#variable-size-list-layout
   
   **We need to establish what constitutes a valid slice**
   
   As I pointed out here 
https://github.com/apache/arrow/pull/37877#discussion_r1343041091 requiring the 
offsets to be within-bounds forbids the naturally occurring 
`child_data[0].length()` offset.
   
   Would it be enough to require that `sizes[i] == 0` when `i` is null to call 
it a "valid empty list-view"? @pitrou


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