From 80b0888fa172090c91588142a5f964cc158cb5c8 Mon Sep 17 00:00:00 2001
From: Will Jones <willjones127@gmail.com>
Date: Sun, 17 Sep 2023 06:35:14 -0400
Subject: [PATCH] fix: export record batch through stream (#4806)

* fix: export record batch through stream

* Update arrow/src/pyarrow.rs

---------

Co-authored-by: Raphael Taylor-Davies <1781103+tustvold@users.noreply.github.com>
---
 .../tests/test_sql.py                         | 17 ++++++++++
 arrow/src/pyarrow.rs                          | 31 ++++++-------------
 2 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/arrow-pyarrow-integration-testing/tests/test_sql.py b/arrow-pyarrow-integration-testing/tests/test_sql.py
index 3be5b9ec52fe..1748fd3ffb6b 100644
--- a/arrow-pyarrow-integration-testing/tests/test_sql.py
+++ b/arrow-pyarrow-integration-testing/tests/test_sql.py
@@ -393,6 +393,23 @@ def test_sparse_union_python():
     del a
     del b
 
+def test_tensor_array():
+    tensor_type = pa.fixed_shape_tensor(pa.float32(), [2, 3])
+    inner = pa.array([float(x) for x in range(1, 7)] + [None] * 12, pa.float32())
+    storage = pa.FixedSizeListArray.from_arrays(inner, 6)
+    f32_array = pa.ExtensionArray.from_storage(tensor_type, storage)
+
+    # Round-tripping as an array gives back storage type, because arrow-rs has
+    # no notion of extension types.
+    b = rust.round_trip_array(f32_array)
+    assert b == f32_array.storage
+
+    batch = pa.record_batch([f32_array], ["tensor"])
+    b = rust.round_trip_record_batch(batch)
+    assert b == batch
+
+    del b
+
 def test_record_batch_reader():
     """
     Python -> Rust -> Python
diff --git a/arrow/src/pyarrow.rs b/arrow/src/pyarrow.rs
index 6063ae763228..ab0ea8ef8d74 100644
--- a/arrow/src/pyarrow.rs
+++ b/arrow/src/pyarrow.rs
@@ -59,14 +59,14 @@ use std::convert::{From, TryFrom};
 use std::ptr::{addr_of, addr_of_mut};
 use std::sync::Arc;
 
-use arrow_array::RecordBatchReader;
+use arrow_array::{RecordBatchIterator, RecordBatchReader};
 use pyo3::exceptions::{PyTypeError, PyValueError};
 use pyo3::ffi::Py_uintptr_t;
 use pyo3::import_exception;
 use pyo3::prelude::*;
-use pyo3::types::{PyDict, PyList, PyTuple};
+use pyo3::types::{PyList, PyTuple};
 
-use crate::array::{make_array, Array, ArrayData};
+use crate::array::{make_array, ArrayData};
 use crate::datatypes::{DataType, Field, Schema};
 use crate::error::ArrowError;
 use crate::ffi;
@@ -270,25 +270,12 @@ impl FromPyArrow for RecordBatch {
 
 impl ToPyArrow for RecordBatch {
     fn to_pyarrow(&self, py: Python) -> PyResult<PyObject> {
-        let mut py_arrays = vec![];
-
-        let schema = self.schema();
-        let columns = self.columns().iter();
-
-        for array in columns {
-            py_arrays.push(array.to_data().to_pyarrow(py)?);
-        }
-
-        let py_schema = schema.to_pyarrow(py)?;
-
-        let module = py.import("pyarrow")?;
-        let class = module.getattr("RecordBatch")?;
-        let args = (py_arrays,);
-        let kwargs = PyDict::new(py);
-        kwargs.set_item("schema", py_schema)?;
-        let record = class.call_method("from_arrays", args, Some(kwargs))?;
-
-        Ok(PyObject::from(record))
+        // Workaround apache/arrow#37669 by returning RecordBatchIterator
+        let reader =
+            RecordBatchIterator::new(vec![Ok(self.clone())], self.schema().clone());
+        let reader: Box<dyn RecordBatchReader + Send> = Box::new(reader);
+        let py_reader = reader.into_pyarrow(py)?;
+        py_reader.call_method0(py, "read_next_batch")
     }
 }