[pull] main from python:main

Doc/library/imaplib.rst

@@ -328,6 +328,19 @@ An :class:`IMAP4` instance has the following methods:
    of the IMAP4 QUOTA extension defined in rfc2087.
 
 
+.. method:: IMAP4.id(fields=None)
+
+   Send client identification information to the server
+   and return the identification information sent back by the server
+   (the ``ID`` command, defined in :rfc:`2971`).
+   *fields* is a mapping of field names to values
+   (for example, ``{'name': 'myclient', 'version': '1.0'}``);
+   a value can be ``None``.
+   The server must support the ``ID`` capability.
+
+   .. versionadded:: next
+
+
 .. method:: IMAP4.idle(duration=None)
 
    Return an :class:`!Idler`: an iterable context manager implementing the
@@ -430,13 +443,30 @@ An :class:`IMAP4` instance has the following methods:
 .. method:: IMAP4.login_cram_md5(user, password)
 
    Force use of ``CRAM-MD5`` authentication when identifying the client to protect
-   the password.  Will only work if the server ``CAPABILITY`` response includes the
-   phrase ``AUTH=CRAM-MD5``.
+   the password. It will only work if the server ``CAPABILITY`` response includes
+   the phrase ``AUTH=CRAM-MD5``.
 
    .. versionchanged:: 3.15
       An :exc:`IMAP4.error` is raised if MD5 support is not available.
 
 
+.. method:: IMAP4.login_plain(user, password)
+
+   Authenticate using the ``PLAIN`` SASL mechanism (:rfc:`4616`).
+
+   This is a plaintext authentication mechanism that can be used instead
+   of :meth:`login` when UTF-8 support is required (see :rfc:`6855`).
+   Since the credentials are only base64-encoded, not encrypted, this
+   method should only be used over a TLS-protected connection, such as
+   :class:`IMAP4_SSL` or after :meth:`starttls`.
+
+   It will only work if the server supports the ``PLAIN`` mechanism,
+   which it need not advertise as ``AUTH=PLAIN`` in its ``CAPABILITY``
+   response.
+
+   .. versionadded:: next
+
+
 .. method:: IMAP4.logout()
 
    Shutdown connection to server. Returns server ``BYE`` response.

Doc/whatsnew/3.16.rst

@@ -231,10 +231,19 @@ io
 imaplib
 -------
 
+* Add the :meth:`~imaplib.IMAP4.id` method,
+  a wrapper for the ``ID`` command (:rfc:`2971`).
+  (Contributed by Serhiy Storchaka in :gh:`98092`.)
+
 * Add the :meth:`~imaplib.IMAP4.move` method,
   a wrapper for the ``MOVE`` command (:rfc:`6851`).
   (Contributed by Serhiy Storchaka in :gh:`77508`.)
 
+* Add the :meth:`~imaplib.IMAP4.login_plain` method, which authenticates
+  using the ``PLAIN`` SASL mechanism (:rfc:`4616`) and supports non-ASCII
+  user names and passwords.
+  (Contributed by Przemysław Buczkowski and Serhiy Storchaka in :gh:`89869`.)
+
 
 logging
 -------

Lib/imaplib.py

@@ -73,6 +73,7 @@
         'GETANNOTATION':('AUTH', 'SELECTED'),
         'GETQUOTA':     ('AUTH', 'SELECTED'),
         'GETQUOTAROOT': ('AUTH', 'SELECTED'),
+        'ID':           ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
         'IDLE':         ('AUTH', 'SELECTED'),
         'MYRIGHTS':     ('AUTH', 'SELECTED'),
         'LIST':         ('AUTH', 'SELECTED'),
@@ -697,6 +698,28 @@ def getquotaroot(self, mailbox):
         return typ, [quotaroot, quota]
 
 
+    def id(self, fields=None):
+        """Send client identification information to the server.
+
+        (typ, [data]) = <instance>.id(fields)
+
+        'fields' is a mapping of field names to values; a value can be
+        None.  'data' is the identification information sent back by
+        the server, in the same parenthesized list form.
+        """
+        name = 'ID'
+        if fields:
+            items = []
+            for field, value in fields.items():
+                items.append(self._quote(field))
+                items.append(b'NIL' if value is None else self._quote(value))
+            arg = b'(' + b' '.join(items) + b')'
+        else:
+            arg = 'NIL'
+        typ, dat = self._simple_command(name, arg)
+        return self._untagged_response(typ, dat, name)
+
+
     def idle(self, duration=None):
         """Return an iterable IDLE context manager producing untagged responses.
         If the argument is not None, limit iteration to 'duration' seconds.
@@ -739,6 +762,30 @@ def login(self, user, password):
         return typ, dat
 
 
+    def login_plain(self, user, password):
+        """Authenticate using the PLAIN SASL mechanism (RFC 4616).
+
+        This is a plaintext authentication mechanism that can be used
+        instead of login() when UTF-8 support is required.  Since the
+        credentials are only base64-encoded, not encrypted, it should
+        only be used over a TLS-protected connection.
+
+        'user' and 'password' can be strings (encoded to UTF-8) or
+        bytes-like objects.
+        """
+        if isinstance(user, str):
+            user = user.encode('utf-8')
+        if isinstance(password, str):
+            password = password.encode('utf-8')
+        if b'\0' in user or b'\0' in password:
+            raise ValueError("NUL is not allowed in user name or password")
+        # An empty authorization identity (RFC 4616) makes the server
+        # derive it from the authentication identity; a non-empty one
+        # requests proxy authorization and is often rejected.
+        response = b'\0' + bytes(user) + b'\0' + bytes(password)
+        return self.authenticate("PLAIN", lambda _: response)
+
+
     def login_cram_md5(self, user, password):
         """ Force use of CRAM-MD5 authentication.
 

Lib/multiprocessing/managers.py

@@ -1294,9 +1294,9 @@ class SyncManager(BaseManager):
     class _SharedMemoryTracker:
         "Manages one or more shared memory segments."
 
-        def __init__(self, name, segment_names=[]):
+        def __init__(self, name, segment_names=None):
             self.shared_memory_context_name = name
-            self.segment_names = segment_names
+            self.segment_names = [] if segment_names is None else segment_names
 
         def register_segment(self, segment_name):
             "Adds the supplied shared memory block name to tracker."

Lib/test/test_imaplib.py

@@ -420,6 +420,15 @@ def cmd_AUTHENTICATE(self, tag, args):
             self._send_tagged(tag, 'NO', 'No access')
 
 
+class AuthHandler_PLAIN(SimpleIMAPHandler):
+    capabilities = 'LOGINDISABLED AUTH=PLAIN'
+    def cmd_AUTHENTICATE(self, tag, args):
+        self.server.auth_args = args
+        self._send_textline('+')
+        self.server.response = yield
+        self._send_tagged(tag, 'OK', 'Logged in.')
+
+
 class NewIMAPTestsMixin:
     client = None
 
@@ -692,6 +701,35 @@ def test_login_cram_md5_blocked(self):
         with self.assertRaisesRegex(imaplib.IMAP4.error, msg):
             client.login_cram_md5("tim", b"tanstaaftanstaaf")
 
+    def test_login_plain_ascii(self):
+        client, server = self._setup(AuthHandler_PLAIN)
+        self.assertIn('AUTH=PLAIN', client.capabilities)
+        ret, _ = client.login_plain("prem", "pass")
+        self.assertEqual(ret, "OK")
+        self.assertEqual(server.auth_args, ['PLAIN'])
+        self.assertEqual(server.response, b'AHByZW0AcGFzcw==\r\n')
+
+    def test_login_plain_utf8(self):
+        client, server = self._setup(AuthHandler_PLAIN)
+        self.assertIn('AUTH=PLAIN', client.capabilities)
+        ret, _ = client.login_plain("pręm", "żółć")
+        self.assertEqual(ret, "OK")
+        self.assertEqual(server.response, b'AHByxJltAMW8w7PFgsSH\r\n')
+
+    def test_login_plain_bytes(self):
+        # bytes are accepted and sent verbatim (not re-encoded).
+        client, server = self._setup(AuthHandler_PLAIN)
+        ret, _ = client.login_plain(b'pr\xc4\x99m', b'\xc5\xbc\xc3\xb3\xc5\x82\xc4\x87')
+        self.assertEqual(ret, "OK")
+        self.assertEqual(server.response, b'AHByxJltAMW8w7PFgsSH\r\n')
+
+    def test_login_plain_nul(self):
+        client, _ = self._setup(AuthHandler_PLAIN)
+        with self.assertRaises(ValueError):
+            client.login_plain('user\0', 'pass')
+        with self.assertRaises(ValueError):
+            client.login_plain('user', b'pa\0ss')
+
     def test_aborted_authentication(self):
         class MyServer(SimpleIMAPHandler):
             def cmd_AUTHENTICATE(self, tag, args):
@@ -1701,6 +1739,24 @@ def test_getquotaroot(self):
         self.assertEqual(typ, 'OK')
         self.assertEqual(server.args, ['"New folder"'])
 
+    def test_id(self):
+        client, server = self._setup(make_simple_handler('ID',
+            ['* ID ("name" "Cyrus" "version" "1.5")']))
+        typ, data = client.id({'name': 'imaplib', 'version': '3.16'})
+        self.assertEqual(typ, 'OK')
+        self.assertEqual(data, [b'("name" "Cyrus" "version" "1.5")'])
+        self.assertEqual(server.args, ['("name" "imaplib" "version" "3.16")'])
+
+        typ, data = client.id()
+        self.assertEqual(typ, 'OK')
+        self.assertEqual(server.args, ['NIL'])
+
+        # Fields and values are quoted strings; a None value is sent
+        # as NIL.
+        typ, data = client.id({'name': 'my "client"', 'os': None})
+        self.assertEqual(typ, 'OK')
+        self.assertEqual(server.args, [r'("name" "my \"client\"" "os" NIL)'])
+
     def test_setquota(self):
         client, server = self._setup(make_simple_handler('SETQUOTA',
             ['* QUOTA "" (STORAGE 512)']))

Misc/ACKS

@@ -260,6 +260,7 @@ Stan Bubrouski
 Brandt Bucher
 Curtis Bucher
 Colm Buckley
+Przemysław Buczkowski
 Erik de Bueger
 Jan-Hein Bührman
 Marc Bürg

Misc/NEWS.d/next/Library/2026-07-05-20-15-00.gh-issue-98092.iDcmd1.rst

@@ -0,0 +1,2 @@
+Add :meth:`imaplib.IMAP4.id`, a wrapper for the IMAP ``ID`` command
+(:rfc:`2971`).

Misc/NEWS.d/next/Library/2026-07-05-21-40-00.gh-issue-89869.XG7aHz.rst

@@ -0,0 +1,3 @@
+Add :meth:`imaplib.IMAP4.login_plain`, which authenticates using the
+``PLAIN`` SASL mechanism (:rfc:`4616`).  Unlike :meth:`~imaplib.IMAP4.login`,
+it supports non-ASCII user names and passwords.