gh-100374: Fixed a bug in socket.getfqdn() (gh-100375)

(cherry picked from commit 12be23cf3c1301be2c6b8fd4cb2cd35a567d2ea2)

Co-authored-by: Dominic Socular <BBH@awsl.rip>

diff --git a/Lib/socket.py b/Lib/socket.py
index 63ba0acc908c3c08c2a26bb47d3987fdf501afda..310b074ca27876888fb4dcacab50044c9c708e43 100644 (file)
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -783,11 +783,11 @@ def getfqdn(name=''):
 
     First the hostname returned by gethostbyaddr() is checked, then
     possibly existing aliases. In case no FQDN is available and `name`
-    was given, it is returned unchanged. If `name` was empty or '0.0.0.0',
+    was given, it is returned unchanged. If `name` was empty, '0.0.0.0' or '::',
     hostname from gethostname() is returned.
     """
     name = name.strip()
-    if not name or name == '0.0.0.0':
+    if not name or name in ('0.0.0.0', '::'):
         name = gethostname()
     try:
         hostname, aliases, ipaddrs = gethostbyaddr(name)

diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index e0e0f2437bb07a0b20ce67c80812688b2bcb74b2..211fd8c02da0a4141e85fa1d26444939d2e52c1e 100644 (file)
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1743,6 +1743,10 @@ class GeneralModuleTests(unittest.TestCase):
         )
         self.assertEqual(sockaddr, ('ff02::1de:c0:face:8d', 1234, 0, 0))
 
+    def test_getfqdn_filter_localhost(self):
+        self.assertEqual(socket.getfqdn(), socket.getfqdn("0.0.0.0"))
+        self.assertEqual(socket.getfqdn(), socket.getfqdn("::"))
+
     @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 required for this test.')
     @unittest.skipIf(sys.platform == 'win32', 'does not work on Windows')
     @unittest.skipIf(AIX, 'Symbolic scope id does not work')

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-12-20-16-14-19.gh-issue-100374.YRrVHT.rst b/Misc/NEWS.d/next/Core and Builtins/2022-12-20-16-14-19.gh-issue-100374.YRrVHT.rst
new file mode 100644 (file)
index 0000000..e78352f
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-12-20-16-14-19.gh-issue-100374.YRrVHT.rst
@@ -0,0 +1 @@
+Fix incorrect result and delay in :func:`socket.getfqdn`. Patch by Dominic Socular.