show error message when we try to connect anonymously to a server that doesn't support anonymous connection. Fixes #8138

src/common/connection.py

@@ -2860,6 +2860,12 @@ class Connection(CommonConnection, ConnectionHandlers):
         self.connection.send(iq)
 
     def get_password(self, callback, type_):
+        if gajim.config.get_per('accounts', self.name, 'anonymous_auth') and \
+        type_ != 'ANONYMOUS':
+            gajim.nec.push_incoming_event(NonAnonymousServerErrorEvent(None,
+                conn=self))
+            self._on_disconnected()
+            return
         self.pasword_callback = (callback, type_)
         if type_ == 'X-MESSENGER-OAUTH2':
             client_id = gajim.config.get_per('accounts', self.name,

src/common/connection_handlers_events.py

@@ -1924,6 +1924,10 @@ class PrivacyListActiveDefaultEvent(nec.NetworkIncomingEvent):
     name = 'privacy-list-active-default'
     base_network_events = []
 
+class NonAnonymousServerErrorEvent(nec.NetworkIncomingEvent):
+    name = 'non-anonymous-server-error'
+    base_network_events = []
+
 class VcardReceivedEvent(nec.NetworkIncomingEvent):
     name = 'vcard-received'
     base_network_events = []

src/gui_interface.py

@@ -1376,6 +1376,13 @@ class Interface:
         self.instances[account]['online_dialog']['ssl_error'].set_title(
             _('SSL Certificate Verification for %s') % account)
 
+    def handle_event_non_anonymous_server(self, obj):
+        account = obj.conn.name
+        server = gajim.config.get_per('accounts', account, 'hostname')
+        dialogs.ErrorDialog(_('Non Anonymous Server'), sectext='Server "%s"'
+            'does not support anonymous connection' % server,
+            transient_for=self.roster.window)
+
     def handle_event_fingerprint_error(self, obj):
         # ('FINGERPRINT_ERROR', account, (new_fingerprint_sha1,new_fingerprint_sha256,))
         account = obj.conn.name
@@ -1579,6 +1586,7 @@ class Interface:
                 [self.handle_event_roster_item_exchange],
             'signed-in': [self.handle_event_signed_in],
             'ssl-error': [self.handle_event_ssl_error],
+            'non-anonymous-server-error': [self.handle_event_non_anonymous_server],
             'stream-conflict-received': [self.handle_event_resource_conflict],
             'subscribe-presence-received': [
                 self.handle_event_subscribe_presence],