Add support for Guild.system_channel

4 files changed, 36 insertions, 2 deletions

diff --git a/discord/audit_logs.py b/discord/audit_logs.py
index 16c79aad..c33f8c32 100644
--- a/discord/audit_logs.py
+++ b/discord/audit_logs.py
@@ -105,6 +105,7 @@ class AuditLogChanges:
         'inviter_id':              ('inviter', _transform_inviter_id),
         'channel_id':              ('channel', _transform_channel),
         'afk_channel_id':          ('afk_channel', _transform_channel),
+        'system_channel_id':       ('system_channel', _transform_channel),
         'widget_channel_id':       ('widget_channel', _transform_channel),
         'permission_overwrites':   ('overwrites', _transform_overwrites),
         'splash_hash':             ('splash', None),
diff --git a/discord/guild.py b/discord/guild.py
index 5900623f..3f7b7270 100644
--- a/discord/guild.py
+++ b/discord/guild.py
@@ -122,7 +122,7 @@ class Guild(Hashable):
                  '_default_role', 'roles', '_member_count', '_large',
                  'owner_id', 'mfa_level', 'emojis', 'features',
                  'verification_level', 'explicit_content_filter', 'splash',
-                 '_voice_states' )
+                 '_voice_states', '_system_channel_id', )
 
     def __init__(self, *, data, state):
         self._channels = {}
@@ -214,6 +214,7 @@ class Guild(Hashable):
         self.emojis = tuple(map(lambda d: self._state.store_emoji(self, d), guild.get('emojis', [])))
         self.features = guild.get('features', [])
         self.splash = guild.get('splash')
+        self._system_channel_id = guild.get('system_channel_id')
 
         for mdata in guild.get('members', []):
             member = Member(data=mdata, guild=self, state=self._state)
@@ -309,6 +310,15 @@ class Guild(Hashable):
         return self._channels.get(channel_id)
 
     @property
+    def system_channel(self):
+        """Optional[:class:`TextChannel`]: Returns the guild's channel used for system messages.
+
+        Currently this is only for new member joins. If no channel is set, then this returns ``None``.
+        """
+        channel_id = self._system_channel_id
+        return channel_id and self._channels.get(channel_id)
+
+    @property
     def members(self):
         """List[:class:`Member`]: A list of members that belongs to this guild."""
         return list(self._members.values())
@@ -627,6 +637,8 @@ class Guild(Hashable):
             The new verification level for the guild.
         vanity_code: str
             The new vanity code for the guild.
+        system_channel: Optional[:class:`TextChannel`]
+            The new channel that is used for the system channel. Could be ``None`` for no system channel.
         reason: Optional[str]
             The reason for editing this guild. Shows up on the audit log.
 
@@ -683,6 +695,16 @@ class Guild(Hashable):
             else:
                 fields['afk_channel_id'] = afk_channel.id
 
+        try:
+            system_channel = fields.pop('system_channel')
+        except KeyError:
+            pass
+        else:
+            if system_channel is None:
+                fields['system_channel_id'] = system_channel
+            else:
+                fields['system_channel_id'] = system_channel.id
+
         if 'owner' in fields:
             if self.owner != self.me:
                 raise InvalidArgument('To transfer ownership you must be the owner of the guild.')
diff --git a/discord/http.py b/discord/http.py
index b935cf99..57f99244 100644
--- a/discord/http.py
+++ b/discord/http.py
@@ -543,7 +543,8 @@ class HTTPClient:
 
     def edit_guild(self, guild_id, *, reason=None, **fields):
         valid_keys = ('name', 'region', 'icon', 'afk_timeout', 'owner_id',
-                      'afk_channel_id', 'splash', 'verification_level')
+                      'afk_channel_id', 'splash', 'verification_level',
+                      'system_channel_id')
 
         payload = {
             k: v for k, v in fields.items() if k in valid_keys
diff --git a/docs/api.rst b/docs/api.rst
index 24347d00..c0816af0 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -886,6 +886,7 @@ All enumerations are subclasses of `enum`_.
         Possible attributes for :class:`AuditLogDiff`:
 
         - :attr:`~AuditLogDiff.afk_channel`
+        - :attr:`~AuditLogDiff.system_channel`
         - :attr:`~AuditLogDiff.afk_timeout`
         - :attr:`~AuditLogDiff.default_message_notifications`
         - :attr:`~AuditLogDiff.explicit_content_filter`
@@ -1491,6 +1492,15 @@ this goal, it must make use of a couple of data classes that aid in this goal.
 
         See :attr:`Guild.afk_channel`.
 
+    .. attribute:: system_channel
+
+        Union[:class:`TextChannel`, :class:`Object`] – The guild's system channel.
+
+        If this could not be found, then it falls back to a :class:`Object`
+        with the ID being set.
+
+        See :attr:`Guild.system_channel`.
+
     .. attribute:: afk_timeout
 
         *int* – The guild's AFK timeout. See :attr:`Guild.afk_timeout`.