bpo-37322: Fix ResourceWarning and exception handling in test (GH-25553)

Revert 73ea546, increase logging, and improve stability of test.

Handle all OSErrors in a single block. OSError also takes care of
SSLError and socket's connection errors.

Partly reverts commit fb7e750. The
threaded connection handler must not raise an unhandled exception.

Lib/test/test_ssl.py

@@ -2390,7 +2390,10 @@ class ThreadedEchoServer(threading.Thread):
                         sys.stdout.write(" client cert is " + pprint.pformat(cert) + "\n")
                     cert_binary = self.sslconn.getpeercert(True)
                     if support.verbose and self.server.chatty:
-                        sys.stdout.write(" cert binary is " + str(len(cert_binary)) + " bytes\n")
+                        if cert_binary is None:
+                            sys.stdout.write(" client did not provide a cert\n")
+                        else:
+                            sys.stdout.write(f" cert binary is {len(cert_binary)}b\n")
                 cipher = self.sslconn.cipher()
                 if support.verbose and self.server.chatty:
                     sys.stdout.write(" server: connection cipher is now " + str(cipher) + "\n")
@@ -2486,31 +2489,22 @@ class ThreadedEchoServer(threading.Thread):
                             sys.stdout.write(" server: read %r (%s), sending back %r (%s)...\n"
                                              % (msg, ctype, msg.lower(), ctype))
                         self.write(msg.lower())
-                except (ConnectionResetError, ConnectionAbortedError):
-                    # XXX: OpenSSL 1.1.1 sometimes raises ConnectionResetError
-                    # when connection is not shut down gracefully.
+                except OSError as e:
+                    # handles SSLError and socket errors
                     if self.server.chatty and support.verbose:
-                        sys.stdout.write(
-                            " Connection reset by peer: {}\n".format(
-                                self.addr)
+                        if isinstance(e, ConnectionError):
+                            # OpenSSL 1.1.1 sometimes raises
+                            # ConnectionResetError when connection is not
+                            # shut down gracefully.
+                            print(
+                                f" Connection reset by peer: {self.addr}"
                             )
-                    self.close()
-                    self.running = False
-                except ssl.SSLError as err:
-                    # On Windows sometimes test_pha_required_nocert receives the
-                    # PEER_DID_NOT_RETURN_A_CERTIFICATE exception
-                    # before the 'tlsv13 alert certificate required' exception.
-                    # If the server is stopped when PEER_DID_NOT_RETURN_A_CERTIFICATE
-                    # is received test_pha_required_nocert fails with ConnectionResetError
-                    # because the underlying socket is closed
-                    if 'PEER_DID_NOT_RETURN_A_CERTIFICATE' == err.reason:
-                        if self.server.chatty and support.verbose:
-                            sys.stdout.write(err.args[1])
-                        # test_pha_required_nocert is expecting this exception
-                        raise ssl.SSLError('tlsv13 alert certificate required')
-                except OSError:
-                    if self.server.chatty:
+                        else:
                             handle_error("Test server failure:\n")
+                    try:
+                        self.write(b"ERROR\n")
+                    except OSError:
+                        pass
                     self.close()
                     self.running = False
 
@@ -4416,23 +4410,29 @@ class TestPostHandshakeAuth(unittest.TestCase):
         server_context.verify_mode = ssl.CERT_REQUIRED
         client_context.post_handshake_auth = True
 
-        # Ignore expected SSLError in ConnectionHandler of ThreadedEchoServer
-        # (it is only raised sometimes on Windows)
-        with threading_helper.catch_threading_exception() as cm:
-            server = ThreadedEchoServer(context=server_context, chatty=False)
+        def msg_cb(conn, direction, version, content_type, msg_type, data):
+            if support.verbose and content_type == _TLSContentType.ALERT:
+                info = (conn, direction, version, content_type, msg_type, data)
+                sys.stdout.write(f"TLS: {info!r}\n")
+
+        server_context._msg_callback = msg_cb
+        client_context._msg_callback = msg_cb
+
+        server = ThreadedEchoServer(context=server_context, chatty=True)
         with server:
             with client_context.wrap_socket(socket.socket(),
                                             server_hostname=hostname) as s:
                 s.connect((HOST, server.port))
                 s.write(b'PHA')
+                with self.assertRaisesRegex(
+                    ssl.SSLError,
+                    'tlsv13 alert certificate required'
+                ):
                     # receive CertificateRequest
                     self.assertEqual(s.recv(1024), b'OK\n')
                     # send empty Certificate + Finish
                     s.write(b'HASCERT')
                     # receive alert
-                    with self.assertRaisesRegex(
-                            ssl.SSLError,
-                            'tlsv13 alert certificate required'):
                     s.recv(1024)
 
     def test_pha_optional(self):