apacheGH-41884: [Python] Fix RecordBatchReader.cast to support castin…

…g to equal schema for all types

python/pyarrow/src/arrow/python/ipc.cc

@@ -79,7 +79,8 @@ Status CastingRecordBatchReader::Init(std::shared_ptr<RecordBatchReader> parent,
 
   // Ensure all columns can be cast before succeeding
   for (int i = 0; i < num_fields; i++) {
-    if (!compute::CanCast(*src->field(i)->type(), *schema->field(i)->type())) {
+    if ((!((src->field(i)->type()->Equals(schema->field(i)->type())))) &&
+        (!compute::CanCast(*src->field(i)->type(), *schema->field(i)->type()))) {
       return Status::TypeError("Field ", i, " cannot be cast from ",
                                src->field(i)->type()->ToString(), " to ",
                                schema->field(i)->type()->ToString());

python/pyarrow/tests/test_ipc.py

@@ -16,6 +16,7 @@
 # under the License.
 
 from collections import UserList
+import datetime
 import io
 import pathlib
 import pytest
@@ -1272,6 +1273,15 @@ def test_record_batch_reader_cast():
     with pytest.raises(pa.lib.ArrowTypeError, match='Field 0 cannot be cast'):
         reader.cast(pa.schema([pa.field('a', pa.list_(pa.int32()))]))
 
+    # Cast to same type should always work also for date32
+    # (https://github.com/apache/arrow/issues/41884)
+    schema_src = pa.schema([pa.field('a', pa.date32())])
+    arr = pa.array([datetime.date(2024, 6, 11)], type=pa.date32())
+    data = [pa.record_batch([arr], names=['a']), pa.record_batch([arr], names=['a'])]
+    table_src = pa.Table.from_batches(data)
+    reader = pa.RecordBatchReader.from_batches(schema_src, data)
+    assert reader.cast(schema_src).read_all() == table_src
+
 
 def test_record_batch_reader_cast_nulls():
     schema_src = pa.schema([pa.field('a', pa.int64())])