mod_roster_command: Fix subscription when the "user JID" is a bare domain. Do not attempt to update the roster when the user is bare domain (e.g. a component), since they don't have rosters and the attempt results in an error: $ prosodyctl mod_roster_command subscribe proxy.example.com contact@example.com xxxxxxxxxxFailed to execute command: Error: /usr/lib/prosody/core/rostermanager.lua:104: attempt to concatenate local 'username' (a nil value) stack traceback: /usr/lib/prosody/core/rostermanager.lua:104: in function 'load_roster' /usr/lib/prosody/core/rostermanager.lua:305: in function 'set_contact_pending_out' mod_roster_command.lua:44: in function 'subscribe'

---
labels:
- 'Stage-Alpha'
summary: 'Support XEP-0334: Message Processing Hints for MUC messages'
...

Introduction
============

This module will check for MUC messages with XEP-0334 Message
Processing Hints tags to qualify those messages as "historic"
for later MAM archiving or not.

Usage
=====

First copy the module to the prosody plugins directory.

Then add "muc\_mam\_hints" to your modules\_enabled list in your MUC
component:

``` {.lua}
Component "conference.example.org" "muc"
modules_enabled = {
  "muc_mam",
  "muc_mam_hints",
}
```