Restore previous Windows behaviour

Author: barneygale

Doc/library/pathlib.rst

@@ -872,10 +872,11 @@ conforming to :rfc:`8089`.
    .. versionadded:: 3.13
 
    .. versionchanged:: 3.14
-      On non-Windows platforms, if a URL authority (e.g. a hostname) is
-      present, then it is discarded if it resolves to ``localhost``, otherwise
-      :exc:`ValueError` is raised. In previous versions the authority is
-      included in the returned path.
+      If a URL authority (e.g. a hostname) is present and resolves to
+      ``localhost``, it is discarded. If an authority is present and
+      *doesn't* resolve to ``localhost``, then on Windows a UNC path is
+      returned (as before), and on other platforms a :exc:`ValueError` is
+      raised.
 
 .. method:: Path.as_uri()
 

Doc/library/urllib.request.rst

@@ -182,10 +182,11 @@ The :mod:`urllib.request` module defines the following functions:
       'C:\\Program Files'
 
    .. versionchanged:: 3.14
-      On non-Windows platforms, if a URL authority (e.g. a hostname) is
-      present, then it is discarded if it resolves to ``localhost``, otherwise
-      :exc:`~urllib.error.URLError` is raised. In previous versions the
-      authority is included in the returned path.
+      If a URL authority (e.g. a hostname) is present and resolves to
+      ``localhost``, it is discarded. If an authority is present and
+      *doesn't* resolve to ``localhost``, then on Windows a UNC path is
+      returned (as before), and on other platforms a
+      :exc:`~urllib.error.URLError` is raised.
 
    .. versionchanged:: 3.14
       Windows drive letters are no longer converted to uppercase, and ``:``

Lib/test/test_pathlib/test_pathlib.py

@@ -3284,7 +3284,9 @@ def test_from_uri_posix(self):
         self.assertEqual(P.from_uri('file:////foo/bar'), P('//foo/bar'))
         self.assertEqual(P.from_uri('file://localhost/foo/bar'), P('/foo/bar'))
         self.assertEqual(P.from_uri('file://127.0.0.1/foo/bar'), P('/foo/bar'))
-        self.assertEqual(P.from_uri(f'file://{socket.gethostname()}/foo/bar'), P('/foo/bar'))
+        if not is_wasi:
+            self.assertEqual(P.from_uri(f'file://{socket.gethostname()}/foo/bar'),
+                             P('/foo/bar'))
         self.assertRaises(ValueError, P.from_uri, 'foo/bar')
         self.assertRaises(ValueError, P.from_uri, '/foo/bar')
         self.assertRaises(ValueError, P.from_uri, '//foo/bar')

Lib/test/test_urllib2.py

@@ -816,17 +816,14 @@ def test_file(self):
         urls = [
             canonurl,
             parsed._replace(netloc='localhost').geturl(),
+            parsed._replace(netloc=socket.gethostbyname('localhost')).geturl(),
             ]
-        if os.name != 'nt':
-            # On POSIX the local hostname may appear in a local file URL.
-            # On Windows this would be decoded as a UNC path.
-            urls.append(parsed._replace(netloc=socket.gethostbyname('localhost')).geturl())
-            try:
-                localaddr = socket.gethostbyname(socket.gethostname())
-            except socket.gaierror:
-                localaddr = ''
-            if localaddr:
-                urls.append(parsed._replace(netloc=localaddr).geturl())
+        try:
+            localaddr = socket.gethostbyname(socket.gethostname())
+        except socket.gaierror:
+            localaddr = ''
+        if localaddr:
+            urls.append(parsed._replace(netloc=localaddr).geturl())
 
         for url in urls:
             f = open(TESTFN, "wb")

Lib/urllib/request.py

@@ -1639,7 +1639,7 @@ def url2pathname(url):
     to a file system path; not recommended for general use."""
     authority, url = _splithost(url)
     if os.name == 'nt':
-        if authority and authority != 'localhost':
+        if not _is_local_authority(authority):
             # e.g. file://server/share/file.txt
             url = '//' + authority + url
         elif url[:3] == '///':

Misc/NEWS.d/next/Library/2024-11-14-21-17-48.gh-issue-126838.Yr5vKF.rst

@@ -1,6 +1,5 @@
 Fix issue where :func:`urllib.request.url2pathname` mishandled file URLs with
-non-empty, non-``localhost`` authorities on non-Windows systems. Authorities
-that resolve to ``localhost`` are now discarded; other authorities now cause
-a :exc:`urllib.error.URLError` to be raised. Previously these authorities
-were incorrectly included in the returned path. This change does not affect
-Windows, where UNC paths are returned for non-local URLs.
+authorities. If an authority is present and resolves to ``localhost``, it is
+now discarded. If an authority is present but *doesn't* resolve to
+``localhost``, then on Windows a UNC path is returned (as before), and on
+other platforms a :exc:`urllib.errors.URLError` is now raised.