assert missing when empty

Author: xanderbailey

pyiceberg/table/metadata.py

@@ -21,9 +21,9 @@
 import uuid
 from collections.abc import Iterable
 from copy import copy
-from typing import Annotated, Any, Literal
+from typing import TYPE_CHECKING, Annotated, Any, Literal
 
-from pydantic import Field, field_serializer, field_validator, model_validator
+from pydantic import Field, field_serializer, field_validator, model_serializer, model_validator
 from pydantic import ValidationError as PydanticValidationError
 
 from pyiceberg.exceptions import ValidationError
@@ -49,6 +49,9 @@
 from pyiceberg.utils.config import Config
 from pyiceberg.utils.datetime import datetime_to_millis
 
+if TYPE_CHECKING:
+    from pydantic.functional_serializers import ModelWrapSerializerWithoutInfo
+
 CURRENT_SNAPSHOT_ID = "current-snapshot-id"
 CURRENT_SCHEMA_ID = "current-schema-id"
 SCHEMAS = "schemas"
@@ -618,6 +621,14 @@ def construct_refs(self) -> TableMetadata:
     encryption_keys: list[EncryptedKey] = Field(alias="encryption-keys", default_factory=list)
     """An optional list of encryption keys used for table encryption."""
 
+    @model_serializer(mode="wrap")
+    def serialize_model(self, handler: ModelWrapSerializerWithoutInfo) -> dict[str, Any]:
+        """Set custom serializer to leave out `encryption-keys` when it is empty."""
+        serialized: dict[str, Any] = handler(self)
+        if not self.encryption_keys:
+            serialized.pop("encryption-keys", None)
+        return serialized
+
     def model_dump_json(self, exclude_none: bool = True, exclude: Any | None = None, by_alias: bool = True, **kwargs: Any) -> str:
         raise NotImplementedError("Writing V3 is not yet supported, see: https://github.com/apache/iceberg-python/issues/1551")
 

tests/table/test_metadata.py

@@ -980,3 +980,15 @@ def test_v3_metadata_without_encryption_keys(example_table_metadata_v3: dict[str
     assert table_metadata.encryption_keys == []
     for snapshot in table_metadata.snapshots:
         assert snapshot.key_id is None
+
+    assert "encryption-keys" not in table_metadata.model_dump(mode="json")
+
+
+def test_v3_metadata_with_encryption_keys_serializes_them(example_table_metadata_v3: dict[str, Any]) -> None:
+    table_metadata = TableMetadataUtil.parse_obj(
+        {**example_table_metadata_v3, "encryption-keys": [{"key-id": "a", "encrypted-key-metadata": "a2V5"}]}
+    )
+
+    assert table_metadata.model_dump(mode="json")["encryption-keys"] == [
+        {"key-id": "a", "encrypted-key-metadata": "a2V5", "properties": {}}
+    ]