From 88134623d6949b4fec1aaaa00d68593049d91481 Mon Sep 17 00:00:00 2001
From: b84330808 <b84330808@gmail.com>
Date: Thu, 29 Oct 2026 10:19:00 +0900
Subject: [PATCH] gh-71468: Make xmlrpc.client.Fault and ProtocolError
 picklable

Both exceptions called Error.__init__() without arguments, so args was
empty and unpickling called the constructor with no arguments, which
raised TypeError. Pass the constructor arguments to Error.__init__(),
as configparser and smtplib exceptions do.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Lib/test/test_xmlrpc.py                       | 24 +++++++++++++++++++
 Lib/xmlrpc/client.py                          |  4 ++--
 ...6-10-29-01-18-55.gh-issue-71468.wZ-CyG.rst |  3 +++
 3 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2026-10-29-01-18-55.gh-issue-71468.wZ-CyG.rst

diff --git a/Lib/test/test_xmlrpc.py b/Lib/test/test_xmlrpc.py
index ee0e24f6e86ae33..0ad365b42b2f3b1 100644
--- a/Lib/test/test_xmlrpc.py
+++ b/Lib/test/test_xmlrpc.py
@@ -1,6 +1,7 @@
 import base64
 import datetime
 import decimal
+import pickle
 import sys
 import time
 import unittest
@@ -480,6 +481,29 @@ def test_dump_fault(self):
         s = xmlrpclib.Marshaller().dumps(f)
         self.assertRaises(xmlrpclib.Fault, xmlrpclib.loads, s)
 
+    def test_pickle(self):
+        # gh-71468
+        f = xmlrpclib.Fault(42, 'Test Fault')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                newf = pickle.loads(pickle.dumps(f, proto))
+                self.assertIs(type(newf), xmlrpclib.Fault)
+                self.assertEqual(newf.faultCode, 42)
+                self.assertEqual(newf.faultString, 'Test Fault')
+
+    def test_protocol_error_pickle(self):
+        # gh-71468
+        e = xmlrpclib.ProtocolError('localhost/RPC2', 500,
+                                    'Internal Server Error', {'X-Test': '1'})
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                newe = pickle.loads(pickle.dumps(e, proto))
+                self.assertIs(type(newe), xmlrpclib.ProtocolError)
+                self.assertEqual(newe.url, 'localhost/RPC2')
+                self.assertEqual(newe.errcode, 500)
+                self.assertEqual(newe.errmsg, 'Internal Server Error')
+                self.assertEqual(newe.headers, {'X-Test': '1'})
+
     def test_dotted_attribute(self):
         # this will raise AttributeError because code don't want us to use
         # private methods
diff --git a/Lib/xmlrpc/client.py b/Lib/xmlrpc/client.py
index 84e4e4d11a7319e..f5afce27ba7996d 100644
--- a/Lib/xmlrpc/client.py
+++ b/Lib/xmlrpc/client.py
@@ -201,7 +201,7 @@ class Error(Exception):
 class ProtocolError(Error):
     """Indicates an HTTP protocol error."""
     def __init__(self, url, errcode, errmsg, headers):
-        Error.__init__(self)
+        Error.__init__(self, url, errcode, errmsg, headers)
         self.url = url
         self.errcode = errcode
         self.errmsg = errmsg
@@ -233,7 +233,7 @@ class ResponseError(Error):
 class Fault(Error):
     """Indicates an XML-RPC fault package."""
     def __init__(self, faultCode, faultString, **extra):
-        Error.__init__(self)
+        Error.__init__(self, faultCode, faultString)
         self.faultCode = faultCode
         self.faultString = faultString
     def __repr__(self):
diff --git a/Misc/NEWS.d/next/Library/2026-10-29-01-18-55.gh-issue-71468.wZ-CyG.rst b/Misc/NEWS.d/next/Library/2026-10-29-01-18-55.gh-issue-71468.wZ-CyG.rst
new file mode 100644
index 000000000000000..3b3e512044e0870
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-10-29-01-18-55.gh-issue-71468.wZ-CyG.rst
@@ -0,0 +1,3 @@
+:class:`xmlrpc.client.Fault` and :class:`xmlrpc.client.ProtocolError`
+exceptions can now be unpickled. Previously, unpickling them raised
+:exc:`TypeError`.