Don’t reflect an empty id if it was not included

Instead, generate a uuid for that message

src/bridge/bridge.cpp

@@ -233,7 +233,7 @@ void Bridge::send_channel_message(const Iid& iid, const std::string& body, std::
         uuid = Database::store_muc_message(this->get_bare_jid(), iid.get_local(), iid.get_server(), std::chrono::system_clock::now(),
                                     std::get<0>(xmpp_body), irc->get_own_nick());
 #endif
-      if (!first)
+      if (!first || id.empty())
         id = utils::gen_uuid();
       for (const auto& resource: this->resources_in_chan[iid.to_tuple()])
         this->xmpp.send_muc_message(std::to_string(iid), irc->get_own_nick(), this->make_xmpp_body(line),

tests/end_to_end/__main__.py

@@ -1227,6 +1227,13 @@ if __name__ == '__main__':
                      partial(expect_stanza,
                          "/message[@from='#foo%{irc_server_one}/{nick_one}'][@id][@to='{jid_one}/{resource_one}'][@type='groupchat']/body[text()='trois']"),
 
+                     # Send a simple message, with no id
+                     partial(send_stanza, "<message from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}' type='groupchat'><body>hello</body></message>"),
+
+                     # Expect a non-empty id as a result (should be a uuid)
+                     partial(expect_stanza,
+                         "!/message[@id='']/body[text()='hello']"),
+
                      # Second user joins
                      partial(send_stanza,
                      "<presence from='{jid_two}/{resource_one}' to='#foo%{irc_server_one}/{nick_two}' />"),