Avoid to acquire the lazy_connect lock if it is not required

cassandra/cqlengine/connection.py

@@ -15,7 +15,6 @@
 from collections import namedtuple, defaultdict
 import logging
 import six
-from warnings import warn
 import threading
 
 from cassandra.cluster import Cluster, _NOT_SET, NoHostAvailable, UserTypeDoesNotExist
@@ -105,14 +104,9 @@ def setup(
     :param list hosts: list of hosts, (``contact_points`` for :class:`cassandra.cluster.Cluster`)
     :param str default_keyspace: The default keyspace to use
     :param int consistency: The global default :class:`~.ConsistencyLevel` - default is the same as :attr:`.Session.default_consistency_level`
-    :param bool lazy_connect: True if should not connect until first use (Deprecated)
+    :param bool lazy_connect: True if should not connect until first use
     :param bool retry_connect: True if we should retry to connect even if there was a connection failure initially
     :param \*\*kwargs: Pass-through keyword arguments for :class:`cassandra.cluster.Cluster`
-
-    .. warning ::
-
-      lazy_connect is deprecated. It will be removed in 3.3.
-
     """
     global cluster, session, lazy_connect_args
 
@@ -123,9 +117,6 @@ def setup(
     models.DEFAULT_KEYSPACE = default_keyspace
 
     if lazy_connect:
-        msg = "lazy_connect is deprecated. It will be removed in 3.3."
-        warn(msg, DeprecationWarning)
-        log.warning(msg)
         kwargs['default_keyspace'] = default_keyspace
         kwargs['consistency'] = consistency
         kwargs['lazy_connect'] = False
@@ -199,12 +190,20 @@ def get_cluster():
 
 def handle_lazy_connect():
     global lazy_connect_args
+
+    # if lazy_connect_args is None, it means the cluster is setup and ready
+    # No need to acquire the lock
+    if not lazy_connect_args:
+        return
+
     with lazy_connect_lock:
+        # lazy_connect_args might have been set to None by another thread while waiting the lock
+        # In this case, do nothing.
         if lazy_connect_args:
             log.debug("lazy connect")
             hosts, kwargs = lazy_connect_args
-            lazy_connect_args = None
             setup(hosts, **kwargs)
+            lazy_connect_args = None
 
 
 def register_udt(keyspace, type_name, klass):