Issue #22435: Fix a file descriptor leak when SocketServer bind fails.

Lib/SocketServer.py

@@ -416,8 +416,12 @@ class TCPServer(BaseServer):
         self.socket = socket.socket(self.address_family,
                                     self.socket_type)
         if bind_and_activate:
+            try:
                 self.server_bind()
                 self.server_activate()
+            except:
+                self.server_close()
+                raise
 
     def server_bind(self):
         """Called by constructor to bind the socket.

Lib/test/test_socketserver.py

@@ -314,6 +314,16 @@ class SocketServerTest(unittest.TestCase):
         for t, s in threads:
             t.join()
 
+    def test_tcpserver_bind_leak(self):
+        # Issue #22435: the server socket wouldn't be closed if bind()/listen()
+        # failed.
+        # Create many servers for which bind() will fail, to see if this result
+        # in FD exhaustion.
+        for i in range(1024):
+            with self.assertRaises(OverflowError):
+                SocketServer.TCPServer((HOST, -1),
+                                       SocketServer.StreamRequestHandler)
+
 
 def test_main():
     if imp.lock_held():

Misc/NEWS

@@ -19,6 +19,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #22435: Fix a file descriptor leak when SocketServer bind fails.
+
 - Issue #21580: Now Tkinter correctly handles binary "data" and "maskdata"
   configure options of tkinter.PhotoImage.