In cases where socket_makers can't be created, raise ClientCannotConnect from.

James William Pye · James William Pye · commit 94cafc09423d · 2009-03-08T16:40:25.000-07:00
This provides a distinction for connection failures and a complete inability
to resolve the sequence of socket makers.

Specifically, no connection attempt was made so there were no connection
failures, but the client cannot connect due to name resolution error.
diff --git a/postgresql/driver/pq3.py b/postgresql/driver/pq3.py
@@ -1987,9 +1987,24 @@ def connect(self, timeout = None):
 		timeout = timeout or self.connector.connect_timeout
 		sslmode = self.connector.sslmode or 'prefer'
 
-		# get the list of sockets to try
-		socket_makers = self.connector.socket_factory_sequence()
 		connection_failures = []
+		socket_makers = ()
+
+		try:
+			# get the list of sockets to try
+			socket_makers = self.connector.socket_factory_sequence()
+		except Exception as exc:
+			err = pg_exc.ClientCannotConnectError(
+				"failed to resolve socket makers",
+				details = {
+					"severity" : "FATAL",
+				},
+				source = 'DRIVER'
+			)
+			self.ife_descend(err)
+			err.database = self
+			err.set_connection_failures(connection_failures)
+			err.raise_exception(raise_from = exc)
 
 		# resolve when to do SSL.
 		with_ssl = zip(repeat(True, len(socket_makers)), socket_makers)
@@ -2016,8 +2031,14 @@ def connect(self, timeout = None):
 		else:
 			raise ValueError("invalid sslmode {0!r}".format(sslmode))
 
-		# for each potential socket connection
+		# can_skip is used when 'prefer' is the sslmode.
+		# if the ssl negotiation returns 'N' (nossl), then
+		# ssl "failed", but the socket is still usable for nossl.
+		# in these cases, can_skip is set to True so that the
+		# subsequent non-ssl attempt is skipped.
 		can_skip = False
+
+		# for each potential socket connection
 		for (dossl, socket_maker) in socket_makers:
 			supported = None
 			if can_skip is True:
@@ -2079,13 +2100,13 @@ def connect(self, timeout = None):
 					(dossl, socket_maker, e)
 				)
 		else:
-			# No servers available.
+			# No servers available. (see the break-statement after establishing)
 			err = pg_exc.ClientCannotConnectError(
 				"failed to connect to server",
 				details = {
 					"severity" : "FATAL",
 				},
-				# It's really a collection of exceptions.
+				# It's really a sequence of exceptions.
 				source = 'DRIVER'
 			)
 			self.ife_descend(err)
