Core: Preserve null operations in inspect.snapshots

pyiceberg/table/inspect.py

@@ -92,7 +92,7 @@ def snapshots(self) -> pa.Table:
                     "committed_at": datetime.fromtimestamp(snapshot.timestamp_ms / 1000.0, tz=timezone.utc),
                     "snapshot_id": snapshot.snapshot_id,
                     "parent_id": snapshot.parent_snapshot_id,
-                    "operation": str(operation),
+                    "operation": operation,
                     "manifest_list": snapshot.manifest_list,
                     "summary": additional_properties,
                 }

tests/table/test_inspect.py

@@ -68,3 +68,15 @@ def test_inspect_entries_and_files_render_null_bound(catalog: InMemoryCatalog) -
     files_metrics = tbl.inspect.files().to_pydict()["readable_metrics"][0]["s"]
     assert files_metrics["lower_bound"] is None
     assert files_metrics["upper_bound"] is None
+
+
+def test_inspect_snapshots_preserves_null_operation(catalog: InMemoryCatalog) -> None:
+    schema = Schema(NestedField(1, "s", StringType(), required=False))
+    tbl = catalog.create_table("default.snapshot_without_summary", schema)
+    tbl.append(pa.table({"s": ["value"]}, schema=pa.schema([pa.field("s", pa.large_string(), nullable=True)])))
+
+    snapshots = list(tbl.metadata.snapshots)
+    snapshots[0] = snapshots[0].model_copy(update={"summary": None})
+    tbl.metadata = tbl.metadata.model_copy(update={"snapshots": snapshots})
+
+    assert tbl.inspect.snapshots().to_pydict()["operation"] == [None]