Return PyValueError for nullable PyArrow struct imports

arrow-pyarrow-testing/tests/pyarrow.rs

@@ -41,9 +41,9 @@ use arrow_array::builder::{BinaryViewBuilder, StringViewBuilder};
 use arrow_array::{
     Array, ArrayRef, BinaryViewArray, Int32Array, RecordBatch, StringArray, StringViewArray,
 };
-use arrow_schema::Schema;
 use arrow_pyarrow::{FromPyArrow, ToPyArrow};
-use pyo3::exceptions::PyTypeError;
+use arrow_schema::Schema;
+use pyo3::exceptions::{PyTypeError, PyValueError};
 use pyo3::types::{PyAnyMethods, PyModule};
 use pyo3::{IntoPyObject, Python};
 use std::ffi::CString;
@@ -83,7 +83,7 @@ fn test_to_pyarrow_pair() {
         let tuple = (record_batch.clone(), record_batch).into_pyobject(py)?;
         Vec::<RecordBatch>::from_pyarrow_bound(&tuple)
     })
-        .unwrap();
+    .unwrap();
     assert_eq!(input, res[0]);
     assert_eq!(input, res[1]);
 }
@@ -156,7 +156,7 @@ class NotACapsule:
 value = NotACapsule()
 "#,
         )
-            .unwrap();
+        .unwrap();
 
         let module = PyModule::from_code(py, code.as_c_str(), c"test.py", c"test_module").unwrap();
         let value = module.getattr("value").unwrap();
@@ -170,6 +170,35 @@ value = NotACapsule()
     });
 }
 
+#[test]
+fn test_from_pyarrow_nullable_struct_array() {
+    Python::initialize();
+
+    Python::attach(|py| {
+        let code = CString::new(
+            r#"
+import pyarrow as pa
+
+value = pa.array(
+    [{"a": 1}, None],
+    type=pa.struct([pa.field("a", pa.int32())]),
+)
+"#,
+        )
+        .unwrap();
+
+        let module = PyModule::from_code(py, code.as_c_str(), c"test.py", c"test_module").unwrap();
+        let value = module.getattr("value").unwrap();
+
+        let err = RecordBatch::from_pyarrow_bound(&value).unwrap_err();
+        assert!(err.is_instance_of::<PyValueError>(py));
+        assert_eq!(
+            err.to_string(),
+            "ValueError: Cannot convert nullable StructArray to RecordBatch, see StructArray documentation"
+        );
+    });
+}
+
 fn binary_view_column(num_variadic_buffers: usize) -> BinaryViewArray {
     let long_scalar = b"but soft what light through yonder window breaks".as_slice();
     let mut builder = BinaryViewBuilder::new().with_fixed_block_size(long_scalar.len() as u32);

arrow-pyarrow/src/lib.rs

@@ -305,11 +305,11 @@ impl FromPyArrow for RecordBatch {
             let schema =
                 unsafe { Arc::new(Schema::try_from(schema_ptr.as_ref()).map_err(to_py_err)?) };
             let (_fields, columns, nulls) = array.into_parts();
-            assert_eq!(
-                nulls.map(|n| n.null_count()).unwrap_or_default(),
-                0,
-                "Cannot convert nullable StructArray to RecordBatch, see StructArray documentation"
-            );
+            if nulls.map(|n| n.null_count()).unwrap_or_default() != 0 {
+                return Err(PyValueError::new_err(
+                    "Cannot convert nullable StructArray to RecordBatch, see StructArray documentation",
+                ));
+            }
             return RecordBatch::try_new_with_options(schema, columns, &options).map_err(to_py_err);
         }