[3.13] gh-156713: Use the filesystem encoding in nturl2path (GH-156717) (GH-157425)

urllib.request.pathname2url() and url2pathname() use the filesystem encoding
and error handler since gh-85168, but nturl2path, which implements them on
Windows before 3.14, was left unchanged.  Paths containing surrogate
characters raised UnicodeEncodeError.
(cherry picked from commit 01599e2)

Author: serhiy-storchaka

Lib/nturl2path.py

@@ -14,7 +14,9 @@ def url2pathname(url):
     #   ///C:/foo/bar/spam.foo
     # become
     #   C:\foo\bar\spam.foo
-    import string, urllib.parse
+    import string, sys, urllib.parse
+    encoding = sys.getfilesystemencoding()
+    errors = sys.getfilesystemencodeerrors()
     if url[:3] == '///':
         # URL has an empty authority section, so the path begins on the third
         # character.
@@ -30,13 +32,15 @@ def url2pathname(url):
     if not '|' in url:
         # No drive specifier, just convert slashes
         # make sure not to convert quoted slashes :-)
-        return urllib.parse.unquote(url.replace('/', '\\'))
+        return urllib.parse.unquote(url.replace('/', '\\'),
+                                    encoding=encoding, errors=errors)
     comp = url.split('|')
     if len(comp) != 2 or comp[0][-1] not in string.ascii_letters:
         error = 'Bad URL: ' + url
         raise OSError(error)
     drive = comp[0][-1].upper()
-    tail = urllib.parse.unquote(comp[1].replace('/', '\\'))
+    tail = urllib.parse.unquote(comp[1].replace('/', '\\'),
+                                encoding=encoding, errors=errors)
     return drive + ':' + tail
 
 def pathname2url(p):
@@ -46,7 +50,9 @@ def pathname2url(p):
     #   C:\foo\bar\spam.foo
     # becomes
     #   ///C:/foo/bar/spam.foo
-    import urllib.parse
+    import sys, urllib.parse
+    encoding = sys.getfilesystemencoding()
+    errors = sys.getfilesystemencodeerrors()
     # First, clean up some special forms. We are going to sacrifice
     # the additional information anyway
     p = p.replace('\\', '/')
@@ -58,12 +64,12 @@ def pathname2url(p):
             raise OSError('Bad path: ' + p)
     if not ':' in p:
         # No DOS drive specified, just quote the pathname
-        return urllib.parse.quote(p)
+        return urllib.parse.quote(p, encoding=encoding, errors=errors)
     comp = p.split(':', maxsplit=2)
     if len(comp) != 2 or len(comp[0]) > 1:
         error = 'Bad path: ' + p
         raise OSError(error)
 
     drive = urllib.parse.quote(comp[0].upper())
-    tail = urllib.parse.quote(comp[1])
+    tail = urllib.parse.quote(comp[1], encoding=encoding, errors=errors)
     return '///' + drive + ':' + tail

Lib/test/test_urllib.py

@@ -4,6 +4,7 @@
 import urllib.request
 import urllib.error
 import http.client
+import nturl2path
 import email.message
 import io
 import unittest
@@ -1659,6 +1660,15 @@ def test_pathname2url_nonascii(self):
         url = urllib.parse.quote(os_helper.FS_NONASCII, encoding=encoding, errors=errors)
         self.assertEqual(urllib.request.pathname2url(os_helper.FS_NONASCII), url)
 
+    def test_pathname2url_surrogates(self):
+        # gh-156713: the filesystem encoding and error handler are used,
+        # so that paths containing surrogate characters can be converted.
+        encoding = sys.getfilesystemencoding()
+        errors = sys.getfilesystemencodeerrors()
+        tail = urllib.parse.quote('a\udcff', encoding=encoding, errors=errors)
+        self.assertEqual(nturl2path.pathname2url('C:\\a\udcff'),
+                         '///C:/' + tail)
+
     @unittest.skipUnless(sys.platform == 'win32',
                          'test specific to Windows pathnames.')
     def test_url2pathname_win(self):
@@ -1720,6 +1730,15 @@ def test_url2pathname_nonascii(self):
         url = urllib.parse.quote(url, encoding=encoding, errors=errors)
         self.assertEqual(urllib.request.url2pathname(url), os_helper.FS_NONASCII)
 
+    def test_url2pathname_surrogates(self):
+        # gh-156713: the filesystem encoding and error handler are used, so
+        # that URLs containing percent-encoded surrogates can be converted.
+        encoding = sys.getfilesystemencoding()
+        errors = sys.getfilesystemencodeerrors()
+        url = urllib.parse.quote('a\udcff', encoding=encoding, errors=errors)
+        self.assertEqual(nturl2path.url2pathname('///C:/' + url),
+                         'C:\\a\udcff')
+
 class Utility_Tests(unittest.TestCase):
     """Testcase to test the various utility functions in the urllib."""
 

Misc/NEWS.d/next/Library/2026-08-31-17-10-00.gh-issue-156713.Nt2URL.rst

@@ -0,0 +1,4 @@
+Fix :func:`!nturl2path.pathname2url` and :func:`!nturl2path.url2pathname`:
+the filesystem encoding and error handler are now used for percent-encoding
+and decoding, as in :mod:`urllib.request`.  Previously paths containing
+surrogate characters raised :exc:`UnicodeEncodeError`.