gh-68147: Fix RFC references in imaplib (GH-153126)

Refer to RFC 3501, which obsoleted RFC 2060.  "]" is disallowed
in flags, not in tags.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: serhiy-storchaka

Doc/library/imaplib.rst

@@ -16,7 +16,7 @@
 This module defines three classes, :class:`IMAP4`, :class:`IMAP4_SSL` and
 :class:`IMAP4_stream`, which encapsulate a connection to an IMAP4 server and
 implement a large subset of the IMAP4rev1 client protocol as defined in
-:rfc:`2060`. It is backward compatible with IMAP4 (:rfc:`1730`) servers, but
+:rfc:`3501`. It is backward compatible with IMAP4 (:rfc:`1730`) servers, but
 note that the ``STATUS`` command is not supported in IMAP4.
 
 .. include:: ../includes/wasm-notavail.rst
@@ -632,7 +632,7 @@ An :class:`IMAP4` instance has the following methods:
 .. method:: IMAP4.store(message_set, command, flag_list)
 
    Alters flag dispositions for messages in mailbox.  *command* is specified by
-   section 6.4.6 of :rfc:`2060` as being one of "FLAGS", "+FLAGS", or "-FLAGS",
+   section 6.4.6 of :rfc:`3501` as being one of "FLAGS", "+FLAGS", or "-FLAGS",
    optionally with a suffix of ".SILENT".
 
    For example, to set the delete flag on all messages::
@@ -646,11 +646,11 @@ An :class:`IMAP4` instance has the following methods:
 
       Creating flags containing ']' (for example: "[test]") violates
       :rfc:`3501` (the IMAP protocol).  However, imaplib has historically
-      allowed creation of such tags, and popular IMAP servers, such as Gmail,
+      allowed creation of such flags, and popular IMAP servers, such as Gmail,
       accept and produce such flags.  There are non-Python programs which also
-      create such tags.  Although it is an RFC violation and IMAP clients and
+      create such flags.  Although it is an RFC violation and IMAP clients and
       servers are supposed to be strict, imaplib still continues to allow
-      such tags to be created for backward compatibility reasons, and as of
+      such flags to be created for backward compatibility reasons, and as of
       Python 3.6, handles them if they are sent from the server, since this
       improves real-world compatibility.
 

Lib/imaplib.py

@@ -1,6 +1,6 @@
 """IMAP4 client.
 
-Based on RFC 2060.
+Based on RFC 3501.
 
 Public class:           IMAP4
 Public variable:        Debug
@@ -43,8 +43,8 @@
 AllowedVersions = ('IMAP4REV1', 'IMAP4')        # Most recent first
 
 # Maximal line length when calling readline(). This is to prevent
-# reading arbitrary length lines. RFC 3501 and 2060 (IMAP 4rev1)
-# don't specify a line length. RFC 2683 suggests limiting client
+# reading arbitrary length lines. RFC 3501 (IMAP 4rev1)
+# doesn't specify a line length. RFC 2683 suggests limiting client
 # command lines to 1000 octets and that servers should be prepared
 # to accept command lines up to 8000 octets, so we used to use 10K here.
 # In the modern world (eg: gmail) the response to, for example, a

Lib/test/test_imaplib.py

@@ -1895,8 +1895,8 @@ def test_connect(self):
     @threading_helper.reap_threads
     def test_bracket_flags(self):
 
-        # This violates RFC 3501, which disallows ']' characters in tag names,
-        # but imaplib has allowed producing such tags forever, other programs
+        # This violates RFC 3501, which disallows ']' characters in flags,
+        # but imaplib has allowed producing such flags forever, other programs
         # also produce them (eg: OtherInbox's Organizer app as of 20140716),
         # and Gmail, for example, accepts them and produces them.  So we
         # support them.  See issue #21815.