Fix add_files with non-identity transforms

pyiceberg/io/pyarrow.py

@@ -2241,29 +2241,36 @@ def _partition_value(self, partition_field: PartitionField, schema: Schema) -> A
         if partition_field.source_id not in self.column_aggregates:
             return None
 
-        if not partition_field.transform.preserves_order:
+        source_field = schema.find_field(partition_field.source_id)
+        iceberg_transform = partition_field.transform
+
+        if not iceberg_transform.preserves_order:
             raise ValueError(
                 f"Cannot infer partition value from parquet metadata for a non-linear Partition Field: {partition_field.name} with transform {partition_field.transform}"
             )
 
-        lower_value = partition_record_value(
-            partition_field=partition_field,
-            value=self.column_aggregates[partition_field.source_id].current_min,
-            schema=schema,
+        transform_func = iceberg_transform.transform(source_field.field_type)
+
+        lower_value = transform_func(
+            partition_record_value(
+                partition_field=partition_field,
+                value=self.column_aggregates[partition_field.source_id].current_min,
+                schema=schema,
+            )
         )
-        upper_value = partition_record_value(
-            partition_field=partition_field,
-            value=self.column_aggregates[partition_field.source_id].current_max,
-            schema=schema,
+        upper_value = transform_func(
+            partition_record_value(
+                partition_field=partition_field,
+                value=self.column_aggregates[partition_field.source_id].current_max,
+                schema=schema,
+            )
         )
         if lower_value != upper_value:
             raise ValueError(
                 f"Cannot infer partition value from parquet metadata as there are more than one partition values for Partition Field: {partition_field.name}. {lower_value=}, {upper_value=}"
             )
 
-        source_field = schema.find_field(partition_field.source_id)
-        transform = partition_field.transform.transform(source_field.field_type)
-        return transform(lower_value)
+        return lower_value
 
     def partition(self, partition_spec: PartitionSpec, schema: Schema) -> Record:
         return Record(**{field.name: self._partition_value(field, schema) for field in partition_spec.fields})

tests/integration/test_add_files.py

@@ -33,20 +33,21 @@
 from pyiceberg.catalog import Catalog
 from pyiceberg.exceptions import NoSuchTableError
 from pyiceberg.io import FileIO
-from pyiceberg.io.pyarrow import UnsupportedPyArrowTypeException
+from pyiceberg.io.pyarrow import UnsupportedPyArrowTypeException, schema_to_pyarrow
 from pyiceberg.manifest import DataFile
 from pyiceberg.partitioning import UNPARTITIONED_PARTITION_SPEC, PartitionField, PartitionSpec
 from pyiceberg.schema import Schema
 from pyiceberg.table import Table
 from pyiceberg.table.metadata import TableMetadata
-from pyiceberg.transforms import BucketTransform, IdentityTransform, MonthTransform
+from pyiceberg.transforms import BucketTransform, HourTransform, IdentityTransform, MonthTransform
 from pyiceberg.types import (
     BooleanType,
     DateType,
     IntegerType,
     LongType,
     NestedField,
     StringType,
+    TimestampType,
     TimestamptzType,
 )
 
@@ -898,3 +899,30 @@ def test_add_files_that_referenced_by_current_snapshot_with_check_duplicate_file
     with pytest.raises(ValueError) as exc_info:
         tbl.add_files(file_paths=[existing_files_in_table], check_duplicate_files=True)
     assert f"Cannot add files that are already referenced by table, files: {existing_files_in_table}" in str(exc_info.value)
+
+
+@pytest.mark.integration
+def test_add_files_hour_transform(session_catalog: Catalog) -> None:
+    identifier = "default.test_add_files_hour_transform"
+
+    schema = Schema(NestedField(1, "hourly", TimestampType()))
+    schema_arrow = schema_to_pyarrow(schema, include_field_ids=False)
+    spec = PartitionSpec(PartitionField(source_id=1, field_id=1000, transform=HourTransform(), name="spec_hour"))
+
+    tbl = _create_table(session_catalog, identifier, format_version=1, schema=schema, partition_spec=spec)
+
+    file_path = "s3://warehouse/default/test_add_files_hour_transform/test.parquet"
+
+    from pyiceberg.utils.datetime import micros_to_timestamp
+
+    arrow_table = pa.Table.from_pylist(
+        [{"hourly": micros_to_timestamp(1743465600155254)}, {"hourly": micros_to_timestamp(1743469198047855)}],
+        schema=schema_arrow,
+    )
+
+    fo = tbl.io.new_output(file_path)
+    with fo.create(overwrite=True) as fos:
+        with pq.ParquetWriter(fos, schema=schema_arrow) as writer:
+            writer.write_table(arrow_table)
+
+    tbl.add_files(file_paths=[file_path])