mapleFU commented on PR #43995:
URL: https://github.com/apache/arrow/pull/43995#issuecomment-2334631531

   https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#lists
   
   Without legacy:
   
   > The element field encodes the list's element type and repetition. Element 
repetition must be required or optional.
   
   With backward capability:
   
   Some existing data does not include the inner element layer. For 
backward-compatibility, the type of elements in LIST-annotated structures 
should always be determined by the following rules:
   1. If the repeated field is not a group, then its type is the element type 
and elements are required.
   2. If the repeated field is a group with multiple fields, then its type is 
the element type and elements are required.
   3. If the repeated field is a group with one field and is named either array 
or uses the LIST-annotated group's name with _tuple appended then the repeated 
type is the element type and elements are required.
   4. Otherwise, the repeated field's type is the element type with the 
repeated field's repetition.
   
   So, seems this hit the (1)?
   


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