bpo-32465: Fix proxy_bypass_registry trailing semicolon on Windows

- _proxy_bypass_winreg_override now strips empty values from ProxyOverride
- Added unit test ProxyBypassRegistryTests to check trailing semicolon behavior

Author: PrinceNaroliya

Lib/test/test_urllib.py

@@ -1686,6 +1686,21 @@ def test_with_method_arg(self):
         request.method = 'HEAD'
         self.assertEqual(request.get_method(), 'HEAD')
 
+class ProxyBypassRegistryTests(unittest.TestCase):
+    def test_proxy_bypass_registry_trailing_semicolon(self):
+        fake_proxy_override = "localhost;*.example.com;"
+
+        # Monkeypatch registry reader
+        original_getproxies_registry = urllib.request.getproxies_registry
+        urllib.request.getproxies_registry = lambda: {"no": fake_proxy_override}
+
+        try:
+            self.assertFalse(urllib.request.proxy_bypass("notmatching.com"))
+            self.assertTrue(urllib.request.proxy_bypass("localhost"))
+            self.assertTrue(urllib.request.proxy_bypass("sub.example.com"))
+        finally:
+            urllib.request.getproxies_registry = original_getproxies_registry
+
 
 if __name__ == '__main__':
     unittest.main()

Lib/urllib/request.py

@@ -1996,7 +1996,7 @@ def ip2num(ipAddr):
 
 
 # Same as _proxy_bypass_macosx_sysconf, testable on all platforms
-def _proxy_bypass_winreg_override(host, override):
+def _proxy_bypass_winreg_override(host, proxyOverride):
     """Return True if the host should bypass the proxy server.
 
     The proxy override list is obtained from the Windows
@@ -2008,15 +2008,18 @@ def _proxy_bypass_winreg_override(host, override):
     from fnmatch import fnmatch
 
     host, _ = _splitport(host)
-    proxy_override = override.split(';')
-    for test in proxy_override:
-        test = test.strip()
+
+    # Split and remove empty or whitespace-only entries
+    proxyOverride = [x.strip() for x in proxyOverride.split(';') if x.strip()]
+
+    for test in proxyOverride:
         # "<local>" should bypass the proxy server for all intranet addresses
         if test == '<local>':
             if '.' not in host:
                 return True
         elif fnmatch(host, test):
             return True
+
     return False