rdblue commented on code in PR #6437: URL: https://github.com/apache/iceberg/pull/6437#discussion_r1051674469
########## python/pyiceberg/io/pyarrow.py: ########## @@ -437,3 +459,120 @@ def visit_or(self, left_result: pc.Expression, right_result: pc.Expression) -> p def expression_to_pyarrow(expr: BooleanExpression) -> pc.Expression: return boolean_expression_visit(expr, _ConvertToArrowExpression()) + + +class _ConstructFinalSchema(SchemaVisitor[pa.ChunkedArray]): + file_schema: Schema + table: pa.Table + + def __init__(self, file_schema: Schema, table: pa.Table): + self.file_schema = file_schema + self.table = table + + def schema(self, schema: Schema, struct_result: List[pa.ChunkedArray]) -> pa.Table: + return pa.table(struct_result, schema=schema_to_pyarrow(schema)) + + def struct(self, _: StructType, field_results: List[pa.ChunkedArray]) -> List[pa.ChunkedArray]: + return field_results + + def field(self, field: NestedField, _: pa.ChunkedArray) -> pa.ChunkedArray: + column_name = self.file_schema.find_column_name(field.field_id) + + if column_name: + column_idx = self.table.schema.get_field_index(column_name) + else: + column_idx = -1 + + expected_arrow_type = schema_to_pyarrow(field.field_type) + + # The idx will be -1 when the column can't be found + if column_idx >= 0: + column_field: pa.Field = self.table.schema[column_idx] + column_arrow_type: pa.DataType = column_field.type + column_data: pa.ChunkedArray = self.table[column_idx] + file_type = self.file_schema.find_type(field.field_id) + + # In case of schema evolution + if column_arrow_type != expected_arrow_type: + # To check if the promotion is allowed + _ = promote(file_type, field.field_type) + column_data = column_data.cast(expected_arrow_type) + else: + import numpy as np + + column_data = pa.array(np.full(shape=len(self.table), fill_value=None), type=expected_arrow_type) + return column_data + + def list(self, _: ListType, element_result: pa.ChunkedArray) -> pa.ChunkedArray: + pass + + def map(self, _: MapType, key_result: pa.ChunkedArray, value_result: pa.ChunkedArray) -> pa.DataType: + pass + + def primitive(self, primitive: PrimitiveType) -> pa.ChunkedArray: + pass + + +def to_final_schema(final_schema: Schema, schema: Schema, table: pa.Table) -> pa.Table: Review Comment: I don't think it is very clear what "final" means in this context. We usually refer to this as the "requested" or "expected" schema. We may want to rename to use that convention. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org