Fixed bug calculating property max_identifier_length in thick mode when

using older client libraries (#395).

Author: anthony-tuininga

doc/src/api_manual/connection.rst

@@ -760,7 +760,11 @@ Connection Attributes
     in bytes supported by the database to which the connection has been
     established.  See `Database Object Naming Rules
     <https://www.oracle.com/pls/topic/lookup?ctx=dblatest&
-    id=GUID-75337742-67FD-4EC0-985F-741C93D918DA>`__.
+    id=GUID-75337742-67FD-4EC0-985F-741C93D918DA>`__. The value may be
+    ``None``, 30, or 128. The value ``None`` indicates the size cannot be
+    reliably determined by python-oracledb, which occurs when using Thick mode
+    with Oracle Client libraries 12.1 (or older) to connect to Oracle Database
+    12.2, or later.
 
     .. versionadded:: 2.5.0
 

doc/src/release_notes.rst

@@ -14,6 +14,15 @@ of python-oracledb), as affecting the optional :ref:`Thick Mode
 oracledb 2.5.1 (TBD)
 --------------------
 
+Thick Mode Changes
+++++++++++++++++++
+
+#)  Fixed bug calculating property :data:`Connection.max_identifier_length`
+    when using Oracle Client libraries 12.1, or older. The returned value may
+    now be ``None`` when the size cannot be reliably determined by
+    python-oracledb, which occurs when using Oracle Client libraries 12.1 (or
+    older) to connect to Oracle Database 12.2, or later.
+    (`ODPI-C <https://github.com/oracle/odpi>`__ dependency update).
 
 oracledb 2.5.0 (November 2024)
 ------------------------------

src/oracledb/impl/thick/connection.pyx

@@ -666,7 +666,8 @@ cdef class ThickConnImpl(BaseConnImpl):
         cdef dpiConnInfo info
         if dpiConn_getInfo(self._handle, &info) < 0:
             _raise_from_odpi()
-        return info.maxIdentifierLength
+        if info.maxIdentifierLength != 0:
+            return info.maxIdentifierLength
 
     def get_max_open_cursors(self):
         cdef uint32_t value