This PR fixes schema evolution for list types with struct element types and map types with struct value types. Previously, add column commands were generated for each struct element in the collection. If the collection size was greater than one, then multiple add column commands were generated for the same struct. The schema update would then fail due to duplicate column names.
This PR fixes schema evolution for list types with struct element types and map types with struct value types. Previously, add column commands were generated for each struct element in the collection. If the collection size was greater than one, then multiple add column commands were generated for the same struct. The schema update would then fail due to duplicate column names.