Add guild_ready_timeout to control the timeout of GUILD_CREATE stream

This also fixes a timing issue where READY would take far too long to
load for big bot authors.

Closes Rapptz#4112

discord/client.py

@@ -159,6 +159,11 @@ class Client:
         WebSocket in the case of not receiving a HEARTBEAT_ACK. Useful if
         processing the initial packets take too long to the point of disconnecting
         you. The default timeout is 60 seconds.
+    guild_ready_timeout: :class:`float`
+        The maximum number of seconds to wait for the GUILD_CREATE stream to end before
+        preparing the member cache and firing READY. The default timeout is 2 seconds.
+
+        .. versionadded:: 1.4
     guild_subscriptions: :class:`bool`
         Whether to dispatching of presence or typing events. Defaults to ``True``.
 

discord/state.py

@@ -80,6 +80,10 @@ def __init__(self, *, dispatch, handlers, hooks, syncer, http, loop, **options):
         self._ready_task = None
         self._fetch_offline = options.get('fetch_offline_members', True)
         self.heartbeat_timeout = options.get('heartbeat_timeout', 60.0)
+        self.guild_ready_timeout = options.get('guild_ready_timeout', 2.0)
+        if self.guild_ready_timeout < 0:
+            raise ValueError('guild_ready_timeout cannot be negative')
+
         self.guild_subscriptions = options.get('guild_subscriptions', True)
         allowed_mentions = options.get('allowed_mentions')
 
@@ -369,10 +373,10 @@ async def _delay_ready(self):
             # only real bots wait for GUILD_CREATE streaming
             if self.is_bot:
                 while True:
-                    # this snippet of code is basically waiting 2 seconds
+                    # this snippet of code is basically waiting N seconds
                     # until the last GUILD_CREATE was sent
                     try:
-                        await asyncio.wait_for(launch.wait(), timeout=2.0)
+                        await asyncio.wait_for(launch.wait(), timeout=self.guild_ready_timeout)
                     except asyncio.TimeoutError:
                         break
                     else:
@@ -1086,10 +1090,10 @@ async def _delay_ready(self):
         await self.shards_launched.wait()
         launch = self._ready_state.launch
         while True:
-            # this snippet of code is basically waiting 2 * shard_ids seconds
+            # this snippet of code is basically waiting N seconds
             # until the last GUILD_CREATE was sent
             try:
-                await asyncio.wait_for(launch.wait(), timeout=2.0 * len(self.shard_ids))
+                await asyncio.wait_for(launch.wait(), timeout=self.guild_ready_timeout)
             except asyncio.TimeoutError:
                 break
             else: