From 1d0cf3110288191db3bf07228456a24ddf6d344f Mon Sep 17 00:00:00 2001
From: Seth Larson <seth@python.org>
Date: Thu, 14 May 2026 16:10:39 -0500
Subject: [PATCH 1/2] [3.13] gh-149144: Use decodeURIComponent() for UTF-8
 support in js_output() (GH-149157)

(cherry picked from commit 461b1d96313de02992d284c1782be9aff24586c9)
---
 Lib/http/cookies.py           |    6 +++---
 Lib/test/test_http_cookies.py |   27 ++++++++++++++-------------
 2 files changed, 17 insertions(+), 16 deletions(-)

Index: Python-3.11.15/Lib/http/cookies.py
===================================================================
--- Python-3.11.15.orig/Lib/http/cookies.py	2026-08-08 22:20:13.129398461 +0200
+++ Python-3.11.15/Lib/http/cookies.py	2026-08-08 22:20:17.089716398 +0200
@@ -389,18 +389,18 @@
         return '<%s: %s>' % (self.__class__.__name__, self.OutputString())
 
     def js_output(self, attrs=None):
-        import base64
+        import urllib.parse
         # Print javascript
         output_string = self.OutputString(attrs)
         if _has_control_character(output_string):
             raise CookieError("Control characters are not allowed in cookies")
         # Base64-encode value to avoid template
         # injection in cookie values.
-        output_encoded = base64.b64encode(output_string.encode('utf-8')).decode("ascii")
+        output_encoded = urllib.parse.quote(output_string, safe='', encoding='utf-8')
         return """
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob(\"%s\");
+        document.cookie = decodeURIComponent(\"%s\");
         // end hiding -->
         </script>
         """ % (output_encoded,)
Index: Python-3.11.15/Lib/test/test_http_cookies.py
===================================================================
--- Python-3.11.15.orig/Lib/test/test_http_cookies.py	2026-08-08 22:20:13.131379374 +0200
+++ Python-3.11.15/Lib/test/test_http_cookies.py	2026-08-08 22:20:17.090353950 +0200
@@ -1,5 +1,5 @@
 # Simple test suite for http/cookies.py
-import base64
+import urllib.parse
 import copy
 import unittest
 import doctest
@@ -106,19 +106,19 @@
 
         self.assertEqual(C.output(['path']),
             'Set-Cookie: Customer="WILE_E_COYOTE"; Path=/acme')
-        cookie_encoded = base64.b64encode(b'Customer="WILE_E_COYOTE"; Path=/acme; Version=1').decode('ascii')
+        cookie_encoded = urllib.parse.quote('Customer="WILE_E_COYOTE"; Path=/acme; Version=1', safe='', encoding='utf-8')
         self.assertEqual(C.js_output(), fr"""
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob("{cookie_encoded}");
+        document.cookie = decodeURIComponent("{cookie_encoded}");
         // end hiding -->
         </script>
         """)
-        cookie_encoded = base64.b64encode(b'Customer="WILE_E_COYOTE"; Path=/acme').decode('ascii')
+        cookie_encoded = urllib.parse.quote('Customer="WILE_E_COYOTE"; Path=/acme', safe='', encoding='utf-8')
         self.assertEqual(C.js_output(['path']), fr"""
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob("{cookie_encoded}");
+        document.cookie = decodeURIComponent("{cookie_encoded}");
         // end hiding -->
         </script>
         """)
@@ -215,19 +215,19 @@
 
         self.assertEqual(C.output(['path']),
                          'Set-Cookie: Customer="WILE_E_COYOTE"; Path=/acme')
-        expected_encoded_cookie = base64.b64encode(b'Customer=\"WILE_E_COYOTE\"; Path=/acme; Version=1').decode('ascii')
+        expected_encoded_cookie = urllib.parse.quote('Customer=\"WILE_E_COYOTE\"; Path=/acme; Version=1', safe='', encoding='utf-8')
         self.assertEqual(C.js_output(), fr"""
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob("{expected_encoded_cookie}");
+        document.cookie = decodeURIComponent("{expected_encoded_cookie}");
         // end hiding -->
         </script>
         """)
-        expected_encoded_cookie = base64.b64encode(b'Customer=\"WILE_E_COYOTE\"; Path=/acme').decode('ascii')
+        expected_encoded_cookie = urllib.parse.quote('Customer=\"WILE_E_COYOTE\"; Path=/acme', safe='', encoding='utf-8')
         self.assertEqual(C.js_output(['path']), fr"""
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob("{expected_encoded_cookie}");
+        document.cookie = decodeURIComponent("{expected_encoded_cookie}");
         // end hiding -->
         </script>
         """)
@@ -318,13 +318,14 @@
             self.assertEqual(
                 M.output(),
                 "Set-Cookie: %s=%s; Path=/foo" % (i, "%s_coded_val" % i))
-            expected_encoded_cookie = base64.b64encode(
-                ("%s=%s; Path=/foo" % (i, "%s_coded_val" % i)).encode("ascii")
-            ).decode('ascii')
+            expected_encoded_cookie = urllib.parse.quote(
+                "%s=%s; Path=/foo" % (i, "%s_coded_val" % i),
+                safe='', encoding='utf-8',
+            )
             expected_js_output = """
         <script type="text/javascript">
         <!-- begin hiding
-        document.cookie = atob("%s");
+        document.cookie = decodeURIComponent("%s");
         // end hiding -->
         </script>
         """ % (expected_encoded_cookie,)