Force thin mode to be enabled when creating connections or pools with

asyncio, thus improving the error message and also ensuring that thick
and thin modes to not run concurrently.

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -104,6 +104,10 @@ Common Changes
 #)  All Oracle errors that result in the connection no longer being usable will
     be raised as ``DPY-4011: the database or network closed the connection``
     with the underlying reason being included in the error message.
+#)  Error ``DPY-2053: python-oracledb thin mode cannot be used because thick
+    mode has already been enabled`` is now raised when attempting to use
+    asyncio in thick mode
+    (`issue 448 <https://github.com/oracle/python-oracledb/issues/448>`__).
 #)  Error ``DPY-2056: registered handler for protocol "{protocol}" failed for
     arg "{arg}"`` is now raised when an exception occurs when calling the
     registered handler for a protocol.

src/oracledb/connection.py

@@ -1984,6 +1984,7 @@ def connect_async(
 
         # build connection class and call the implementation connect to
         # actually establish the connection
+        oracledb.enable_thin_mode()
         return conn_class(dsn, pool, params, kwargs)
 
     return connect_async

src/oracledb/pool.py

@@ -1105,6 +1105,7 @@ def create_pool_async(
             params=params,
             **kwargs,
         )
+        oracledb.enable_thin_mode()
         if not issubclass(pool_class, AsyncConnectionPool):
             errors._raise_err(errors.ERR_INVALID_POOL_CLASS)
         return pool_class(dsn, params=params, cache_name=pool_alias, **kwargs)

utils/templates/connection.py

@@ -1747,6 +1747,7 @@ def connect_async(
 
         # build connection class and call the implementation connect to
         # actually establish the connection
+        oracledb.enable_thin_mode()
         return conn_class(dsn, pool, params, kwargs)
 
     return connect_async

utils/templates/pool.py

@@ -799,6 +799,7 @@ def create_pool_async(
             params=params,
             **kwargs,
         )
+        oracledb.enable_thin_mode()
         if not issubclass(pool_class, AsyncConnectionPool):
             errors._raise_err(errors.ERR_INVALID_POOL_CLASS)
         return pool_class(dsn, params=params, cache_name=pool_alias, **kwargs)