relay: fix save of channels when JOIN/PART are received from an IRC relay client (closes #1771)

ChangeLog.adoc

@@ -21,6 +21,7 @@ https://weechat.org/files/releasenotes/ReleaseNotes-devel.html[release notes]
 Bug fixes::
 
   * core: fix bad window size on startup with some terminals like https://github.com/kovidgoyal/kitty[kitty] (issue #1769)
+  * relay: fix save of channels in autojoin option when JOIN and PART commands are received from an IRC relay client (issue #1771)
 
 [[v3.5]]
 == Version 3.5 (2022-03-27)

src/plugins/relay/irc/relay-irc.c

@@ -1600,7 +1600,21 @@ relay_irc_recv (struct t_relay_client *client, const char *data)
     }
     else
     {
-        if (irc_command && weechat_strcasecmp (irc_command, "ping") == 0)
+        if (irc_command && weechat_strcasecmp (irc_command, "join") == 0)
+        {
+            relay_irc_input_send (client, NULL,
+                                  "priority_high",
+                                  "/join %s",
+                                  irc_args);
+        }
+        else if (irc_command && weechat_strcasecmp (irc_command, "part") == 0)
+        {
+            relay_irc_input_send (client, NULL,
+                                  "priority_high",
+                                  "/part %s",
+                                  irc_args);
+        }
+        else if (irc_command && weechat_strcasecmp (irc_command, "ping") == 0)
         {
             relay_irc_sendf (client,
                              ":%s PONG %s :%s",