#21815: violate IMAP RFC to be compatible with, e.g., gmail

and others, including imaplib's own behavior.  I'm applying this only to 3.6
because there's a potential backward compatibility concern: if there are
servers that include ] characters in the 'text' portion of their imap
responses, this code change could introduce a new bug.

Patch by Lita Cho, reviewed by Jessica McKellar, Berker Peksag, Maciej Szulik,
silentghost, and me (I fleshed out the comments with the additional
info/concerns.)

1 files changed, 49 insertions, 0 deletions

diff --git a/Lib/test/test_imaplib.py b/Lib/test/test_imaplib.py
index 07157f5..8e4990b 100644
--- a/Lib/test/test_imaplib.py
+++ b/Lib/test/test_imaplib.py
@@ -243,6 +243,55 @@ class ThreadedNetworkedTests(unittest.TestCase):
             client.shutdown()
 
     @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
+        # 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.
+
+        class BracketFlagHandler(SimpleIMAPHandler):
+
+            def handle(self):
+                self.flags = ['Answered', 'Flagged', 'Deleted', 'Seen', 'Draft']
+                super().handle()
+
+            def cmd_AUTHENTICATE(self, tag, args):
+                self._send_textline('+')
+                self.server.response = yield
+                self._send_tagged(tag, 'OK', 'FAKEAUTH successful')
+
+            def cmd_SELECT(self, tag, args):
+                flag_msg = ' \\'.join(self.flags)
+                self._send_line(('* FLAGS (%s)' % flag_msg).encode('ascii'))
+                self._send_line(b'* 2 EXISTS')
+                self._send_line(b'* 0 RECENT')
+                msg = ('* OK [PERMANENTFLAGS %s \\*)] Flags permitted.'
+                        % flag_msg)
+                self._send_line(msg.encode('ascii'))
+                self._send_tagged(tag, 'OK', '[READ-WRITE] SELECT completed.')
+
+            def cmd_STORE(self, tag, args):
+                new_flags = args[2].strip('(').strip(')').split()
+                self.flags.extend(new_flags)
+                flags_msg = '(FLAGS (%s))' % ' \\'.join(self.flags)
+                msg = '* %s FETCH %s' % (args[0], flags_msg)
+                self._send_line(msg.encode('ascii'))
+                self._send_tagged(tag, 'OK', 'STORE completed.')
+
+        with self.reaped_pair(BracketFlagHandler) as (server, client):
+            code, data = client.authenticate('MYAUTH', lambda x: b'fake')
+            self.assertEqual(code, 'OK')
+            self.assertEqual(server.response, b'ZmFrZQ==\r\n')
+            client.select('test')
+            typ, [data] = client.store(b'1', "+FLAGS", "[test]")
+            self.assertIn(b'[test]', data)
+            client.select('test')
+            typ, [data] = client.response('PERMANENTFLAGS')
+            self.assertIn(b'[test]', data)
+
+    @reap_threads
     def test_issue5949(self):
 
         class EOFHandler(socketserver.StreamRequestHandler):