Align buffers from Python (FFI) (#6472)

* Align buffers in RecordBatch.from_pyarrow_bound

* Update arrow/src/pyarrow.rs

* cargo fmt

---------

Co-authored-by: Andrew Lamb <[email protected]>

Author: EnricoMi

arrow/src/pyarrow.rs

@@ -363,13 +363,19 @@ impl FromPyArrow for RecordBatch {
 
             let schema_ptr = unsafe { schema_capsule.reference::<FFI_ArrowSchema>() };
             let ffi_array = unsafe { FFI_ArrowArray::from_raw(array_capsule.pointer().cast()) };
-            let array_data = unsafe { ffi::from_ffi(ffi_array, schema_ptr) }.map_err(to_py_err)?;
+            let mut array_data =
+                unsafe { ffi::from_ffi(ffi_array, schema_ptr) }.map_err(to_py_err)?;
             if !matches!(array_data.data_type(), DataType::Struct(_)) {
                 return Err(PyTypeError::new_err(
                     "Expected Struct type from __arrow_c_array.",
                 ));
             }
             let options = RecordBatchOptions::default().with_row_count(Some(array_data.len()));
+            // Ensure data is aligned (by potentially copying the buffers).
+            // This is needed because some python code (for example the
+            // python flight client) produces unaligned buffers
+            // See https://github.com/apache/arrow/issues/43552 for details
+            array_data.align_buffers();
             let array = StructArray::from(array_data);
             // StructArray does not embed metadata from schema. We need to override
             // the output schema with the schema from the capsule.