Fixed a bug resultging in a segfault when attempting to use an output

type handler while fetching data frames (#486).

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -27,6 +27,11 @@ Thick Mode Changes
 Common Changes
 ++++++++++++++
 
+#)  Fixed a bug resulting in a segfault when attempting to use an
+    :ref:`output type handler <outputtypehandlers>` while fetching data frames
+    with :meth:`Connection.fetch_df_all()` and
+    :meth:`Connection.fetch_df_batches()`
+    (`issue 486 <https://github.com/oracle/python-oracledb/issues/486>`__).
 #)  Added support for using the Cython 3.1 release
     (`issue 493 <https://github.com/oracle/python-oracledb/issues/493>`__).
 #)  Miscellaneous grammar and spelling fixes by John Bampton

src/oracledb/impl/base/cursor.pyx

@@ -301,11 +301,15 @@ cdef class BaseCursorImpl:
         """
         Return the output type handler to use for the cursor. If one is not
         directly defined on the cursor then the one defined on the connection
-        is used instead.
+        is used instead. When fetching Arrow data, however, no output type
+        handlers are used since for most data no conversion to Python objects
+        ever takes place.
         """
         cdef:
             BaseConnImpl conn_impl
             object type_handler
+        if self.fetching_arrow:
+            return None
         if self.outputtypehandler is not None:
             type_handler = self.outputtypehandler
         else: