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'

---
summary: Prevent unaffiliated MUC participants from sending PMs
---

# Introduction

This module prevents unaffiliated users from sending private messages in
chat rooms, unless someone with an affiliation (member, admin etc)
messages them first.

# Configuration

The module doesn't have any options, just load it onto a MUC component.

``` lua
Component "muc"
modules_enabled = {
    "muc_block_pm";
}
```

# Compatibility

    Branch State
  -------- -----------------
       0.9 Works
      0.10 Should work
      0.11 Should work