Redirect welcome NOTICE to their channel, instead of sending a global one

fix #3236

CHANGELOG.rst

@@ -20,6 +20,8 @@ Version 5.0
    IRC server, with simple text files.
  - The IRC channel configuration form is now also available using the MUC
    configuration, in addition to the ad-hoc command.
+ - Notices starting with [#channel] are considered as welcome messages coming
+   from that channel, instead of private messages.
 
 Version 4.3 - 2017-05-02
 ========================

src/irc/irc_client.cpp

@@ -544,9 +544,18 @@ void IrcClient::forward_server_message(const IrcMessage& message)
 void IrcClient::on_notice(const IrcMessage& message)
 {
   std::string from = message.prefix;
-  const std::string to = message.arguments[0];
+  std::string to = message.arguments[0];
   const std::string body = message.arguments[1];
 
+  // Handle notices starting with [#channame] as if they were sent to that channel
+  if (body.size() > 3 && body[0] == '[')
+    {
+      const auto chan_prefix = body[1];
+      auto end = body.find(']');
+      if (this->chantypes.find(chan_prefix) != this->chantypes.end() && end != std::string::npos)
+        to = body.substr(1, end - 1);
+    }
+
   if (!body.empty() && body[0] == '\01' && body[body.size() - 1] == '\01')
     // Do not forward the notice to the user if it's a CTCP command
     return ;

tests/end_to_end/__main__.py

@@ -1114,6 +1114,19 @@ if __name__ == '__main__':
                              ),
                      partial(expect_stanza, "/message[@from='#bar%{irc_server_one}'][@type='groupchat'][@to='{jid_one}/{resource_one}']/subject[not(text())]"),
                  ]),
+        Scenario("notices",
+                 [
+                     handshake_sequence(),
+                     partial(send_stanza,
+                             "<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}' />"),
+                     connection_sequence("irc.localhost", '{jid_one}/{resource_one}'),
+                     partial(expect_stanza, "/message"),
+                     partial(expect_stanza, "/presence"),
+                     partial(expect_stanza, "/message"),
+
+                     partial(send_stanza, "<message from='{jid_one}/{resource_one}' to='{irc_server_one}' type='chat'><body>NOTICE {nick_one} :[#foo] Hello in a notice.</body></message>"),
+                     partial(expect_stanza, "/message[@from='#foo%{irc_server_one}/{nick_one}'][@type='groupchat']/body[text()='[notice] [#foo] Hello in a notice.']"),
+                 ]),
         Scenario("channel_messages",
                  [
                      handshake_sequence(),