Re-send channel welcome (RPL_NAMREPLY, ...) when re-joining

When joining a channel for the second time, join events are part of the timeline
(not just the state events list), but IRC clients registered the previous PART
so they erased the nick list.

Author: progval

lib/matrix_client/poller.ex

@@ -335,6 +335,7 @@ defmodule M51.MatrixClient.Poller do
       )
       when is_binary(state_key) do
     state = M51.IrcConn.Supervisor.matrix_state(sup_pid)
+    irc_state = M51.IrcConn.Supervisor.state(sup_pid)
     channel = M51.MatrixClient.State.room_irc_channel(state, room_id)
     send = make_send_function(sup_pid, event, write)
 
@@ -357,12 +358,28 @@ defmodule M51.MatrixClient.Poller do
           )
 
         if !state_event and !was_already_member do
-          send.(%M51.Irc.Command{
-            tags: %{"account" => target},
-            source: nick2nuh(target),
-            command: "JOIN",
-            params: [channel, target, target]
-          })
+          my_nick = M51.IrcConn.State.nick(irc_state)
+
+          if sender == my_nick do
+            old_canonical_alias = nil
+            canonical_alias_sender = nil
+
+            send_channel_welcome(
+              sup_pid,
+              room_id,
+              canonical_alias_sender,
+              old_canonical_alias,
+              write,
+              event
+            )
+          else
+            send.(%M51.Irc.Command{
+              tags: %{"account" => target},
+              source: nick2nuh(target),
+              command: "JOIN",
+              params: [channel, target, target]
+            })
+          end
         end
 
       "leave" ->
@@ -1013,14 +1030,15 @@ defmodule M51.MatrixClient.Poller do
     state = M51.IrcConn.Supervisor.matrix_state(sup_pid)
     nick = M51.IrcConn.State.nick(irc_state)
     channel = M51.MatrixClient.State.room_irc_channel(state, room_id)
-    send = make_send_function(sup_pid, event, write)
+    send_join = make_send_function(sup_pid, event, write)
+    send_nonjoin = make_send_function(sup_pid, nil, write)
 
     make_numeric = fn numeric, params ->
       %M51.Irc.Command{source: "server.", command: numeric, params: [nick | params]}
     end
 
     send_numeric = fn numeric, params ->
-      send.(make_numeric.(numeric, params))
+      send_nonjoin.(make_numeric.(numeric, params))
     end
 
     # Join the new channel
@@ -1031,7 +1049,7 @@ defmodule M51.MatrixClient.Poller do
       %M51.Matrix.RoomMember{display_name: nil}
     )
 
-    send.(%M51.Irc.Command{
+    send_join.(%M51.Irc.Command{
       tags: %{"account" => nick},
       source: nick2nuh(nick),
       command: "JOIN",

test/matrix_client/poller_test.exs

@@ -478,6 +478,92 @@ defmodule M51.MatrixClient.PollerTest do
     )
   end
 
+  test "re-joined room" do
+    state_events = [
+      %{
+        "content" => %{"alias" => "#test:example.org"},
+        "event_id" => "$event1",
+        "origin_server_ts" => 1_632_644_251_623,
+        "sender" => "@nick:example.org",
+        "state_key" => "",
+        "type" => "m.room.canonical_alias",
+        "unsigned" => %{}
+      },
+      %{
+        "content" => %{"avatar_url" => nil, "displayname" => "Name 2", "membership" => "join"},
+        "event_id" => "$event2",
+        "origin_server_ts" => 1_632_648_797_438,
+        "sender" => "nick2:example.org",
+        "state_key" => "nick2:example.org",
+        "type" => "m.room.member",
+        "unsigned" => %{}
+      },
+      %{
+        "content" => %{"avatar_url" => nil, "displayname" => "My Name", "membership" => "join"},
+        "event_id" => "$event3",
+        "origin_server_ts" => 1_632_648_797_438,
+        "sender" => "mynick:example.com",
+        "state_key" => "mynick:example.com",
+        "type" => "m.room.member",
+        "unsigned" => %{}
+      }
+    ]
+
+    timeline_events = [
+      %{
+        "content" => %{"membership" => "leave"},
+        "event_id" => "$event3",
+        "origin_server_ts" => 1_632_648_797_438,
+        "sender" => "mynick:example.com",
+        "state_key" => "mynick:example.com",
+        "type" => "m.room.member",
+        "unsigned" => %{}
+      },
+      %{
+        "content" => %{"avatar_url" => nil, "displayname" => "My Name", "membership" => "join"},
+        "event_id" => "$event3",
+        "origin_server_ts" => 1_632_648_797_438,
+        "sender" => "mynick:example.com",
+        "state_key" => "mynick:example.com",
+        "type" => "m.room.member",
+        "unsigned" => %{}
+      }
+    ]
+
+    M51.MatrixClient.Poller.handle_events(self(), %{
+      "rooms" => %{
+        "join" => %{
+          "!testid:example.org" => %{
+            "state" => %{"events" => state_events},
+            "timeline" => %{"events" => timeline_events}
+          }
+        }
+      }
+    })
+
+    # first welcome
+    assert_line(":mynick:[email protected] JOIN :#test:example.org\r\n")
+    assert_line(":server. 331 mynick:example.com :#test:example.org\r\n")
+
+    assert_line(
+      ":server. 353 mynick:example.com = #test:example.org :mynick:example.com nick2:example.org\r\n"
+    )
+
+    assert_line(":server. 366 mynick:example.com #test:example.org :End of /NAMES list\r\n")
+
+    assert_line(":mynick:[email protected] PART :#test:example.org\r\n")
+
+    # second welcome
+    assert_line(":mynick:[email protected] JOIN :#test:example.org\r\n")
+    assert_line(":server. 331 mynick:example.com :#test:example.org\r\n")
+
+    assert_line(
+      ":server. 353 mynick:example.com = #test:example.org :mynick:example.com nick2:example.org\r\n"
+    )
+
+    assert_line(":server. 366 mynick:example.com #test:example.org :End of /NAMES list\r\n")
+  end
+
   test "room name suppression" do
     M51.IrcConn.State.add_capabilities(:process_ircconn_state, [
       :channel_rename,
@@ -725,6 +811,14 @@ defmodule M51.MatrixClient.PollerTest do
       "@msgid=$event7 :mynick:[email protected] JOIN :#test:example.com\r\n"
     )
 
+    assert_line(":server. 331 mynick:example.com :#test:example.com\r\n")
+
+    assert_line(
+      ":server. 353 mynick:example.com = #test:example.com :mynick:example.com nick2:example.com\r\n"
+    )
+
+    assert_line(":server. 366 mynick:example.com #test:example.com :End of /NAMES list\r\n")
+
     assert_line(
       "@msgid=$event4 :mynick:[email protected] KICK #test:example.com nick2:example.com :I don't like you\r\n"
     )