fix(chan): postpone trimming conninfo until `connected` hooks run

Some users expect to get the peer certificate in `connected` hooks, but
the `conninfo` was trimmed before `connected` hooks run.

apps/emqx/src/emqx_channel.erl

@@ -256,9 +256,7 @@ init(
     ),
     {NClientInfo, NConnInfo} = take_ws_cookie(ClientInfo, ConnInfo),
     #channel{
-        %% We remove the peercert because it duplicates to what's stored in the socket,
+        conninfo = NConnInfo,
-        %% Saving a copy here causes unnecessary wast of memory (about 1KB per connection).
-        conninfo = maps:put(peercert, undefined, NConnInfo),
         clientinfo = NClientInfo,
         topic_aliases = #{
             inbound => #{},
@@ -1989,10 +1987,21 @@ ensure_connected(
     NConnInfo = ConnInfo#{connected_at => erlang:system_time(millisecond)},
     ok = run_hooks('client.connected', [ClientInfo, NConnInfo]),
     Channel#channel{
-        conninfo = NConnInfo,
+        conninfo = trim_conninfo(NConnInfo),
         conn_state = connected
     }.
 
+trim_conninfo(ConnInfo) ->
+    maps:without(
+        [
+            %% NOTE
+            %% We remove the peercert because it duplicates what's stored in the socket,
+            %% otherwise it wastes about 1KB per connection.
+            peercert
+        ],
+        ConnInfo
+    ).
+
 %%--------------------------------------------------------------------
 %% Init Alias Maximum
 

apps/emqx/src/emqx_types.erl

@@ -129,7 +129,7 @@
     socktype := socktype(),
     sockname := peername(),
     peername := peername(),
-    peercert := nossl | undefined | esockd_peercert:peercert(),
+    peercert => nossl | undefined | esockd_peercert:peercert(),
     conn_mod := module(),
     proto_name => binary(),
     proto_ver => proto_ver(),