[3.9] gh-108342: Break ref cycle in SSLSocket._create() exc (GH-108344) (#108351)

Explicitly break a reference cycle when SSLSocket._create() raises an
exception. Clear the variable storing the exception, since the
exception traceback contains the variables and so creates a reference
cycle.

This test leak was introduced by the test added for the fix of GH-108310.
(cherry picked from commit 64f99350351bc46e016b2286f36ba7cd669b79e3)

Co-authored-by: Victor Stinner <vstinner@python.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/Lib/ssl.py b/Lib/ssl.py
index ef92e76..cb5ec51 100644
--- a/Lib/ssl.py
+++ b/Lib/ssl.py
@@ -1049,7 +1049,11 @@ class SSLSocket(socket):
                     self.close()
                 except OSError:
                     pass
-                raise notconn_pre_handshake_data_error
+                try:
+                    raise notconn_pre_handshake_data_error
+                finally:
+                    # Explicitly break the reference cycle.
+                    notconn_pre_handshake_data_error = None
         else:
             connected = True