gh-141497: make ipaddress.IP{v4,v6}Network.hosts() return an iterator

Lib/ipaddress.py

@@ -1546,7 +1546,7 @@ def __init__(self, address, strict=True):
         if self._prefixlen == (self.max_prefixlen - 1):
             self.hosts = self.__iter__
         elif self._prefixlen == (self.max_prefixlen):
-            self.hosts = lambda: [IPv4Address(addr)]
+            self.hosts = lambda: iter((IPv4Address(addr),))
 
     @property
     @functools.lru_cache()
@@ -2337,7 +2337,7 @@ def __init__(self, address, strict=True):
         if self._prefixlen == (self.max_prefixlen - 1):
             self.hosts = self.__iter__
         elif self._prefixlen == self.max_prefixlen:
-            self.hosts = lambda: [IPv6Address(addr)]
+            self.hosts = lambda: iter((IPv6Address(addr),))
 
     def hosts(self):
         """Generate Iterator over usable hosts in a network.

Lib/test/test_ipaddress.py

@@ -13,6 +13,7 @@
 import ipaddress
 import weakref
 from test.support import LARGEST, SMALLEST
+from typing import Iterator
 
 
 class BaseTestCase(unittest.TestCase):
@@ -1472,12 +1473,16 @@ def testGetSupernet4(self):
                          self.ipv6_scoped_network.supernet(new_prefix=62))
 
     def testHosts(self):
+        hosts = self.ipv4_network.hosts()
+        self.assertIsInstance(hosts, Iterator)
         hosts = list(self.ipv4_network.hosts())
         self.assertEqual(254, len(hosts))
         self.assertEqual(ipaddress.IPv4Address('1.2.3.1'), hosts[0])
         self.assertEqual(ipaddress.IPv4Address('1.2.3.254'), hosts[-1])
 
         ipv6_network = ipaddress.IPv6Network('2001:658:22a:cafe::/120')
+        hosts = ipv6_network.hosts()
+        self.assertIsInstance(hosts, Iterator)
         hosts = list(ipv6_network.hosts())
         self.assertEqual(255, len(hosts))
         self.assertEqual(ipaddress.IPv6Address('2001:658:22a:cafe::1'), hosts[0])

Misc/NEWS.d/next/Library/2025-11-14-16-24-20.gh-issue-141497.L_CxDJ.rst

@@ -0,0 +1,2 @@
+In :mod:`ipaddress`, ensure that the methods ``IPv6Network.hosts()`` and
+``IPv4Network.hosts()`` always returns an iterator.